Yocto Project - User contributions [en]

Poky-Tiny

2012-11-14T22:51:43Z

Tbird20d: /* exiting the system */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/tmp/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size
and /sys, /proc and /dev omitted:
# find / -type f -xdev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 /etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 /var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 /etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 /etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 /etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 /etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 /usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 /etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 /etc/issue
-rwxr-xr-x 1 root root 93 Nov 13 20:19 /etc/default/devpts
-rw-r--r-- 1 root root 109 Nov 14 00:45 /etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 /etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 /etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 /etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 /etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 /etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 /etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 /etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 /etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 /etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 /init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 /etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 /etc/init.d/halt
-rwxr-xr-x 1 root root 516 Nov 13 20:19 /etc/init.d/umountfs
-rwxr-xr-x 1 root root 526 Nov 13 20:19 /etc/init.d/devpts.sh
-rwxr-xr-x 1 root root 578 Nov 13 20:19 /etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 /etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 /usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 /etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 /etc/rc.local.sample
-rw-r--r-- 1 root root 651 Nov 14 00:22 /etc/syslog-startup.conf.busybox
-rwxr-xr-x 1 root root 660 Nov 13 20:19 /etc/init.d/sysfs.sh
-rw-r--r-- 1 root root 704 Nov 14 00:45 /etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 /etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 /etc/passwd
-rw------- 1 root root 737 Nov 14 22:22 /.ash_history
-rw-r--r-- 1 root root 783 Nov 14 21:24 /etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 /etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 /var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 /etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 /etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 /etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 /etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 /etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 /etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 /etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 /etc/inputrc
-rwxr-xr-x 1 root root 1711 Nov 14 00:22 /etc/init.d/syslog.busybox
-rw-r--r-- 1 root root 1740 Nov 13 20:19 /etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 /etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 /etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 /etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 /etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 /etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 /etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 /etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 /usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 /usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 /etc/init.d/populate-volatile.sh
-rwxr-xr-x 1 root root 6666 Nov 13 20:19 /etc/device_table
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 /usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 /lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 /lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 /etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 /lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 /lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 /lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 /lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 /lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 /lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 /lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 /lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 /lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 /lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 /sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 /bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 /lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T22:50:46Z

Tbird20d: /* Some information about the running system */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/tmp/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size
and /sys, /proc and /dev omitted:
# find / -type f -xdev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 /etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 /var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 /etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 /etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 /etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 /etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 /usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 /etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 /etc/issue
-rwxr-xr-x 1 root root 93 Nov 13 20:19 /etc/default/devpts
-rw-r--r-- 1 root root 109 Nov 14 00:45 /etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 /etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 /etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 /etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 /etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 /etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 /etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 /etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 /etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 /etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 /init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 /etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 /etc/init.d/halt
-rwxr-xr-x 1 root root 516 Nov 13 20:19 /etc/init.d/umountfs
-rwxr-xr-x 1 root root 526 Nov 13 20:19 /etc/init.d/devpts.sh
-rwxr-xr-x 1 root root 578 Nov 13 20:19 /etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 /etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 /usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 /etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 /etc/rc.local.sample
-rw-r--r-- 1 root root 651 Nov 14 00:22 /etc/syslog-startup.conf.busybox
-rwxr-xr-x 1 root root 660 Nov 13 20:19 /etc/init.d/sysfs.sh
-rw-r--r-- 1 root root 704 Nov 14 00:45 /etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 /etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 /etc/passwd
-rw------- 1 root root 737 Nov 14 22:22 /.ash_history
-rw-r--r-- 1 root root 783 Nov 14 21:24 /etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 /etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 /var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 /etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 /etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 /etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 /etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 /etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 /etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 /etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 /etc/inputrc
-rwxr-xr-x 1 root root 1711 Nov 14 00:22 /etc/init.d/syslog.busybox
-rw-r--r-- 1 root root 1740 Nov 13 20:19 /etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 /etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 /etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 /etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 /etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 /etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 /etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 /etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 /usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 /usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 /etc/init.d/populate-volatile.sh
-rwxr-xr-x 1 root root 6666 Nov 13 20:19 /etc/device_table
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 /usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 /lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 /lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 /etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 /lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 /lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 /lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 /lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 /lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 /lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 /lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 /lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 /lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 /lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 /sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 /bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 /lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit the qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T22:40:35Z

Tbird20d: /* Basic use */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/tmp/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size
and /sys, /proc and /dev omitted:
# find / -type f -xdev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 /etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 /var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 /etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 /etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 /etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 /etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 /usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 /etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 /etc/issue
-rwxr-xr-x 1 root root 93 Nov 13 20:19 /etc/default/devpts
-rw-r--r-- 1 root root 109 Nov 14 00:45 /etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 /etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 /etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 /etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 /etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 /etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 /etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 /etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 /etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 /etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 /init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 /etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 /etc/init.d/halt
-rwxr-xr-x 1 root root 516 Nov 13 20:19 /etc/init.d/umountfs
-rwxr-xr-x 1 root root 526 Nov 13 20:19 /etc/init.d/devpts.sh
-rwxr-xr-x 1 root root 578 Nov 13 20:19 /etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 /etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 /usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 /etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 /etc/rc.local.sample
-rw-r--r-- 1 root root 651 Nov 14 00:22 /etc/syslog-startup.conf.busybox
-rwxr-xr-x 1 root root 660 Nov 13 20:19 /etc/init.d/sysfs.sh
-rw-r--r-- 1 root root 704 Nov 14 00:45 /etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 /etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 /etc/passwd
-rw------- 1 root root 737 Nov 14 22:22 /.ash_history
-rw-r--r-- 1 root root 783 Nov 14 21:24 /etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 /etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 /var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 /etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 /etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 /etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 /etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 /etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 /etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 /etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 /etc/inputrc
-rwxr-xr-x 1 root root 1711 Nov 14 00:22 /etc/init.d/syslog.busybox
-rw-r--r-- 1 root root 1740 Nov 13 20:19 /etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 /etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 /etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 /etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 /etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 /etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 /etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 /etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 /usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 /usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 /etc/init.d/populate-volatile.sh
-rwxr-xr-x 1 root root 6666 Nov 13 20:19 /etc/device_table
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 /usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 /lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 /lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 /etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 /lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 /lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 /lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 /lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 /lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 /lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 /lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 /lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 /lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 /lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 /sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 /bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 /lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I'm believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit the qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T22:26:47Z

Tbird20d: /* Some information about the running system */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size
and /sys, /proc and /dev omitted:
# find / -type f -xdev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 /etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 /var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 /etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 /etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 /etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 /etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 /usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 /etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 /etc/issue
-rwxr-xr-x 1 root root 93 Nov 13 20:19 /etc/default/devpts
-rw-r--r-- 1 root root 109 Nov 14 00:45 /etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 /etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 /etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 /etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 /etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 /etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 /etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 /etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 /etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 /etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 /init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 /etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 /etc/init.d/halt
-rwxr-xr-x 1 root root 516 Nov 13 20:19 /etc/init.d/umountfs
-rwxr-xr-x 1 root root 526 Nov 13 20:19 /etc/init.d/devpts.sh
-rwxr-xr-x 1 root root 578 Nov 13 20:19 /etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 /etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 /usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 /etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 /etc/rc.local.sample
-rw-r--r-- 1 root root 651 Nov 14 00:22 /etc/syslog-startup.conf.busybox
-rwxr-xr-x 1 root root 660 Nov 13 20:19 /etc/init.d/sysfs.sh
-rw-r--r-- 1 root root 704 Nov 14 00:45 /etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 /etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 /etc/passwd
-rw------- 1 root root 737 Nov 14 22:22 /.ash_history
-rw-r--r-- 1 root root 783 Nov 14 21:24 /etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 /etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 /var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 /etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 /etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 /etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 /etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 /etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 /etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 /etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 /etc/inputrc
-rwxr-xr-x 1 root root 1711 Nov 14 00:22 /etc/init.d/syslog.busybox
-rw-r--r-- 1 root root 1740 Nov 13 20:19 /etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 /etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 /etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 /etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 /etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 /etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 /etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 /etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 /usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 /usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 /etc/init.d/populate-volatile.sh
-rwxr-xr-x 1 root root 6666 Nov 13 20:19 /etc/device_table
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 /usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 /lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 /lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 /etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 /lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 /lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 /lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 /lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 /lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 /lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 /lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 /lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 /lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 /lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 /sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 /bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 /lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I'm believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit the qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T22:23:39Z

Tbird20d: /* Some information about the running system */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size
and /sys, /proc and /dev omitted:
/ # find / -type f -xdev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 /etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 /etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 /var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 /etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 /etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 /etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 /etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 /etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 /usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 /etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 /etc/issue
-rwxr-xr-x 1 root root 93 Nov 13 20:19 /etc/default/devpts
-rw-r--r-- 1 root root 109 Nov 14 00:45 /etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 /lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 /etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 /etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 /etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 /etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 /etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 /etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 /etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 /etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 /etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 /init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 /etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 /etc/init.d/halt
-rwxr-xr-x 1 root root 516 Nov 13 20:19 /etc/init.d/umountfs
-rwxr-xr-x 1 root root 526 Nov 13 20:19 /etc/init.d/devpts.sh
-rwxr-xr-x 1 root root 578 Nov 13 20:19 /etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 /etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 /usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 /etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 /etc/rc.local.sample
-rw-r--r-- 1 root root 651 Nov 14 00:22 /etc/syslog-startup.conf.busybox
-rwxr-xr-x 1 root root 660 Nov 13 20:19 /etc/init.d/sysfs.sh
-rw-r--r-- 1 root root 704 Nov 14 00:45 /etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 /etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 /etc/passwd
-rw------- 1 root root 737 Nov 14 22:22 /.ash_history
-rw-r--r-- 1 root root 783 Nov 14 21:24 /etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 /etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 /var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 /etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 /etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 /etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 /etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 /etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 /etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 /etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 /etc/inputrc
-rwxr-xr-x 1 root root 1711 Nov 14 00:22 /etc/init.d/syslog.busybox
-rw-r--r-- 1 root root 1740 Nov 13 20:19 /etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 /etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 /etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 /etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 /etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 /etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 /etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 /etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 /usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 /usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 /etc/init.d/populate-volatile.sh
-rwxr-xr-x 1 root root 6666 Nov 13 20:19 /etc/device_table
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 /usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 /lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 /lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 /etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 /lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 /lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 /lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 /lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 /lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 /lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 /lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 /lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 /lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 /lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 /sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 /bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 /lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I'm believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit the qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T22:18:56Z

Tbird20d: /* Invoking qemu with poky-tiny images */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

== Introduction ==
It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart.

=== Basic use ===
To use the poky-tiny distro, adjust the DISTRO setting in your conf/local.conf file.
That is, set it to: "DISTRO=poky-tiny"

poky-tiny does not include a target-side package manager, so it is useful, to avoid
extra dependencies, to use it with the IPKG package management scheme. This is the lightest-weight
package management scheme. Set this in your conf/local.conf file:
PACKAGE_CLASSES ?= "package_ipk"

Then do a basic build of the system:
$ bitbake core-image-minimal

Resulting images should appear in your <build-dir>/deploy/images directory.

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
** The kernel recipe for poky-tiny is in <yocto-dir>/meta/recipes-kernel/linux/linux-yocto-tiny_x.x.bb
* What images are supported?
** As of poky-danny-8.0 (the 1.3 release of yocto), poky-tiny.conf defined the following images: IMAGE_FSTYPES = "ext2 cpio.gz" This means it will build both an ext2 filesystem image, and a cpio.gz image (suitable for use as an initramfs).
* What machines are supported (are there any restrictions)?
** in the kernel recipe file, it has COMPATIBLE_MACHINE="(qemux86)"
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized? (eg. gotchas for adding to IMAGE_INSTALL or IMAGE_FEATURES)?

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead. Here's the template:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Here the actual full command I used:

$ tmp/sysroots/x86_64-linux/usr/bin/qemu-system-i386 -kernel tmp/deploy/images/bzImage-qemux86.bin -initrd tmp/deploy/images/core-image-minimal-qemux86.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

=== Some information about the running system ===
You can poke around, and see the status of various things. 'ps' shows only 22 processes running, with only 3 user-space (ie not kernel threads):

# ps | grep -v [[]
PID USER VSZ STAT COMMAND
1 root 2004 S {init} /bin/sh /init
38 root 2144 S sh
41 root 2144 R ps

So... busybox is really the only executable on the system, and it is providing /bin/sh. /init is a shell script,
which will run /etc/rc.local, if one is present. There's a sample in /etc/rc.local.sample that you can use as a
starting point to customize the init process. If you turn on packages in yocto, there will be init scripts deposited
in /etc/init.d, which you can call from either /init or /etc/rc.local to invoke (none of that fancy sysV rc init scripts here!)

I booted with mem=24M (that was about as small as I could go) and saw the following memory utilization:
# free
total used free shared buffers
Mem: 19724 5944 13780 0 0
-/+ buffers: 5944 13780
Swap: 0 0 0

The filesystem is a little over 3M in size:
# du -sh /
3.2M /

Here's a sample of what the filesystem looks like (as of yocto-danny-8.0), with results sorted by size:

# find . -type f | grep -v /sys | grep -v /proc | grep -v /dev | xargs ls -laSr
-rw-r--r-- 1 root root 0 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.dep
-rw-r--r-- 1 root root 0 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.builtin.bin
-rw-r--r-- 1 root root 0 Nov 14 00:45 ./etc/network/nm-disabled-eth0
-rw-r--r-- 1 root root 0 Nov 14 00:45 ./etc/motd
-rw-r--r-- 1 root root 0 Nov 14 00:14 ./etc/ld.so.conf
-rw-r--r-- 1 root root 0 Nov 14 00:45 ./etc/default/usbd
-rw-r--r-- 1 root root 6 Nov 14 22:05 ./var/volatile/run/ifstate
-rw-r--r-- 1 root root 8 Nov 14 00:45 ./etc/hostname
-rw-r--r-- 1 root root 12 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.symbols.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.dep.bin
-rw-r--r-- 1 root root 12 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.alias.bin
-rw-r--r-- 1 root root 13 Nov 14 21:24 ./etc/version
-rw-r--r-- 1 root root 13 Nov 14 21:24 ./etc/timestamp
-rw-r--r-- 1 root root 26 Nov 14 00:45 ./etc/host.conf
-rw-r--r-- 1 root root 38 Nov 14 00:45 ./etc/filesystems
-rw-r--r-- 1 root root 44 Nov 14 00:45 ./etc/hosts
-rw-r--r-- 1 root root 45 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.alias
-rwxr-xr-x 1 root root 49 Nov 14 00:22 ./usr/share/udhcpc/default.script
-rw-r--r-- 1 root root 49 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.symbols
-rw-r--r-- 1 root root 52 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.devname
-rw-r--r-- 1 root root 72 Nov 14 00:45 ./etc/issue.net
-rw-r--r-- 1 root root 74 Nov 14 00:45 ./etc/issue
-rw-r--r-- 1 root root 109 Nov 14 00:45 ./etc/shells
-rw-r--r-- 1 root root 131 Nov 14 21:24 ./lib/modules/3.4.11-yocto-tiny/modules.softdep
-rw-r--r-- 1 root root 132 Nov 14 00:45 ./etc/network/interfaces
-rwxr-xr-x 1 root root 152 Nov 14 00:45 ./etc/skel/.profile
-rwxr-xr-x 1 root root 270 Nov 13 20:19 ./etc/init.d/hostname.sh
-rwxr-xr-x 1 root root 289 Nov 13 20:19 ./etc/init.d/reboot
-rwxr-xr-x 1 root root 321 Nov 13 20:19 ./etc/init.d/save-rtc.sh
-rwxr-xr-x 1 root root 410 Nov 14 00:45 ./etc/skel/.bashrc
-rwxr-xr-x 1 root root 438 Nov 13 20:19 ./etc/init.d/sendsigs
-rw-r--r-- 1 root root 446 Nov 14 21:23 ./etc/group
-rw-r--r-- 1 root root 465 Nov 14 00:45 ./etc/nsswitch.conf
-rwxr-xr-x 1 root root 473 Nov 14 21:24 ./init
-rwxr-xr-x 1 root root 492 Nov 13 20:19 ./etc/init.d/banner.sh
-rwxr-xr-x 1 root root 510 Nov 13 20:19 ./etc/init.d/halt
-rw------- 1 root root 513 Nov 14 22:11 ./.ash_history
-rwxr-xr-x 1 root root 516 Nov 13 20:19 ./etc/init.d/umountfs
-rwxr-xr-x 1 root root 578 Nov 13 20:19 ./etc/init.d/single
-rwxr-xr-x 1 root root 585 Nov 13 20:19 ./etc/init.d/rmnologin.sh
-rw-r--r-- 1 root root 586 Nov 14 00:20 ./usr/share/run-postinsts/run-postinsts.awk
-rwxr-xr-x 1 root root 609 Nov 14 00:20 ./etc/init.d/run-postinsts
-rwxr-xr-x 1 root root 632 Nov 14 00:45 ./etc/rc.local.sample
-rw-r--r-- 1 root root 704 Nov 14 00:45 ./etc/fstab
-rwxr-xr-x 1 root root 711 Nov 13 20:19 ./etc/init.d/umountnfs.sh
-rw-r--r-- 1 root root 719 Nov 14 21:23 ./etc/passwd
-rw-r--r-- 1 root root 783 Nov 14 21:24 ./etc/ld.so.cache
-rwxr-xr-x 1 root root 809 Nov 14 00:45 ./etc/network/if-pre-up.d/nfsroot
-rw------- 1 root root 836 Nov 14 21:24 ./var/volatile/cache/ldconfig/aux-cache
-rw-r--r-- 1 root root 847 Nov 14 00:45 ./etc/profile
-rwxr-xr-x 1 root root 859 Nov 13 20:19 ./etc/init.d/mountall.sh
-rwxr-xr-x 1 root root 878 Nov 14 00:45 ./etc/init.d/modutils.sh
-rw-r--r-- 1 root root 887 Nov 14 00:45 ./etc/rpc
-rw-r--r-- 1 root root 1123 Nov 13 20:19 ./etc/init.d/functions.initscripts
-rwxr-xr-x 1 root root 1349 Nov 13 20:19 ./etc/init.d/urandom
-rwxr-xr-x 1 root root 1540 Nov 13 20:19 ./etc/init.d/mountnfs.sh
-rw-r--r-- 1 root root 1633 Nov 14 00:45 ./etc/inputrc
-rw-r--r-- 1 root root 1740 Nov 13 20:19 ./etc/default/volatiles/00_core
-rwxr-xr-x 1 root root 1752 Nov 13 20:19 ./etc/init.d/bootmisc.sh
-rwxr-xr-x 1 root root 1909 Nov 14 00:45 ./etc/init.d/networking
-rw-r--r-- 1 root root 2146 Nov 14 00:22 ./etc/busybox.links
-rwxr-xr-x 1 root root 2514 Nov 14 00:22 ./etc/init.d/hwclock.sh
-rwxr-xr-x 1 root root 2548 Nov 14 00:22 ./etc/udhcpc.d/50default
-rw-r--r-- 1 root root 2933 Nov 14 00:45 ./etc/protocols
-rwxr-xr-x 1 root root 3229 Nov 13 20:19 ./etc/init.d/checkroot.sh
-rwxr-xr-x 1 root root 4409 Nov 13 20:16 ./usr/sbin/update-rc.d
-rwxr-xr-x 1 root root 4524 Nov 14 00:45 ./usr/bin/update-alternatives
-rwxr-xr-x 1 root root 5249 Nov 13 20:19 ./etc/init.d/populate-volatile.sh
-rwsr-xr-x 1 root root 9544 Nov 14 00:14 ./usr/lib/eglibc/pt_chown
-rwxr-xr-x 1 root root 9740 Nov 14 00:14 ./lib/libutil-2.16.so
-rwxr-xr-x 1 root root 13828 Nov 14 00:14 ./lib/libdl-2.16.so
-rw-r--r-- 1 root root 19398 Nov 14 00:45 ./etc/services
-rwxr-xr-x 1 root root 22020 Nov 14 00:14 ./lib/libnss_dns-2.16.so
-rwxr-xr-x 1 root root 26064 Nov 14 00:14 ./lib/libcrypt-2.16.so
-rwxr-xr-x 1 root root 30624 Nov 14 00:14 ./lib/librt-2.16.so
-rwxr-xr-x 1 root root 34588 Nov 14 00:14 ./lib/libnss_compat-2.16.so
-rwxr-xr-x 1 root root 46980 Nov 14 00:14 ./lib/libnss_files-2.16.so
-rwxr-xr-x 1 root root 83716 Nov 14 00:14 ./lib/libresolv-2.16.so
-rwxr-xr-x 1 root root 87860 Nov 14 00:14 ./lib/libnsl-2.16.so
-rwxr-xr-x 1 root root 96128 Nov 14 00:14 ./lib/libpthread-2.16.so
-rwxr-xr-x 1 root root 127228 Nov 14 00:14 ./lib/ld-2.16.so
-rwxr-xr-x 1 root root 251328 Nov 14 00:14 ./lib/libm-2.16.so
-rwxr-xr-x 1 root root 524924 Nov 14 00:14 ./sbin/ldconfig
-rwsr-xr-x 1 root root 554820 Nov 14 00:22 ./bin/busybox
-rwxr-xr-x 1 root root 1056128 Nov 14 00:14 ./lib/libc-2.16.so

busybox, ldconfig and libc (and other libc-related libs) make up about 95% of the system.

If busybox were statically linked, and ldconfig and libc were omitted, I'm believe it would
reduce the size of the system substantially.

=== exiting the system ===
There is no 'shutdown' command, but you can use 'ctrl-a to execute a command to the qemu monitor, and 'ctrl-a b' to issue a sysrq to the Linux kernel.
You can do a sysrq-B to do a reboot. Do: ctrl-a h to see available commands, and ctrl-a x to exit the qemu.

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T21:38:53Z

Tbird20d: /* Invoking qemu with poky-tiny images */

Poky-Tiny

2012-11-14T20:55:02Z

Tbird20d:

Poky-Tiny

2012-11-14T20:22:43Z

Tbird20d: /* FAQ */

Poky-Tiny

2012-11-14T20:09:01Z

Tbird20d:

Projects

2012-11-14T19:52:34Z

Tbird20d: /* Welcome to the Projects Page */

== Welcome to the Projects Page ==
* [[AutoBuilder]]
* [[Poky]]
* [[SDK Generator]]
* [[Eclipse Plug-in]]
* [[Anjuta Plug-in]]
* [[Pseudo]]
* [[Swabber]]
* [[Cross-Prelink]]
* [[QA]]
* [[Documentation]]
* [[BSPs]]
* [[Tracing and Profiling]]
* Linux Kernel
** [[Linux_Kernel/Boot_Time|Boot Time]]
** [[Linux_kernel/Image_Size|Image Size]]
* [[Multilib]]
* [[BitBake/GUI|BitBake GUI's]]
* [[x32 abi]]
* [[Baryon]]
* [[Build Appliance Design]]
* [[Hob2 (Hob v2)]]
* [[Web UI]]
* [[OpenGL pass-through in QEMU]]
* [[DLNA Media Server Virtual Appliance]]
* [[Running an x86 Yocto Linux image under QEMU KVM]]
* [[Web Application for Interactive Kiosk Devices]]
* [[Virtualization with KVM]]
* [[Projects/Poky-Tiny]]

Poky-Tiny

2012-11-14T19:51:23Z

Tbird20d: /* uclibc */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file is the routine: features_to_uclibc_settings(),
which maps items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T19:50:56Z

Tbird20d: /* Controlling LIBC features */

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

==== eglibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/eglibc/eglibc-options.inc

Listed in that file are the routines: distro_features_check_deps() and features_to_eglibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific eglibc settings.

==== uclibc ====
To see different options that are available, see the file:
<yocto-dir>/meta/recipes-core/uclibc/uclibc-config.inc

Listed in that file are the routines: features_to_uclibc_settings(),
which map items listed in DISTRO_FEATURES_LIBC into specific uclibc settings.

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T19:43:20Z

Tbird20d: add presentation - adjust headings

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

To see different options that are available, see the file:

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

== Resources ==
* Presentation: [http://elinux.org/images/2/2b/Elce11_hart.pdf Tuning Linux For Embedded Systems: When Less Is More] by Darren Hart, ELC Europe 2011, October 2011, Prague, Czech Republic

Poky-Tiny

2012-11-14T19:40:23Z

Tbird20d:

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions and images
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Adjusting poky-tiny ==
=== Controlling LIBC features ===
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

To see different options that are available, see the file:

=== Controlling kernel features ===

=== Controlling busybox features ===

== Troubleshooting the build ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Poky-Tiny

2012-11-14T19:33:39Z

Tbird20d:

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ ==
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro ==
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Controlling LIBC features ==
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

To see different options that are available, see the file:

== Controlling kernel features ==

== Controlling busybox features ==

== Invoking qemu with poky-tiny images ==
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"

Poky-Tiny

2012-11-14T19:33:09Z

Tbird20d: work-in-progress 1

Poky-tiny is a variant of the poky distribution which is stripped down to minimal configuration.

It is intended to be useful for a few different purposes:
* as a demonstration of techniques useful for reducing other images
* as a springboard for very low-end distributions
* as a place to experiment with whole-system optimization techniques

It was written by Darren Hart, and is available by setting
your DISTRO in conf/local.conf to DISTRO=poky-tiny.

This page is a work in progress - the following sections would be good to fill out:

== FAQ
* where is poky-tiny defined?
** poky-tiny is defined in <yocto-dir>/meta-yocto/conf/distro/poky-tiny.conf. Some other recipes and images have been modified to support the features in poky-tiny.
* What images are supported?
* What machines (are there any restrictions)?
* What features have been eliminated?
* What is the size difference between poky-tiny and poky (core-image-minimal)?
* Are there differences in the way poky-tiny is customized, from the way default 'poky' is customized?
** eg. gotchas for adding to IMAGE_

== Creating your own tiny-based distro
You can create your own distro, based on the tiny work, by copying the poky-tiny.conf file
to your own layer, and editing it from there.

Assuming you are calling your layer 'meta-foo', you could do the following:

* create your meta-foo layer (see other docs for this)
* copy the poky-tiny distro configuration file to your own layer
$ install -p meta-foo/conf/distro
$ cp meta-yocto/conf/distro/poky-tiny.conf meta-foo/conf/distro/foo-tiny.conf
* edit your conf/local.conf to use your foo-tiny.conf distro
$ vi <build-dir>/conf/local.conf
[change it so "DISTRO?=foo-tiny"]

== Controlling LIBC features
Inside foo-tiny.conf (derived from poky-tiny.conf), you can specify what LIBC features to support
by modifying the DISTRO_FEATURES_LIBC variable.

This variable is declared to be a space-separated list of other DISTRO_FEATURES_LIBC_xxx variables.
To turn on or off features in libc, edit the values of these variables.

To see different options that are available, see the file:

== Controlling kernel features

== Controlling busybox features

== Invoking qemu with poky-tiny images
Runqemu doesn't understand poky-tiny (or initramfs?). Try executing qemu directly instead:

$ qemu-system-i386 -kernel path/to/kernel -initrd path/to/image.cpio.gz -nographic -append "console=ttyS0 root=/dev/ram0"