Use i686 as TARGET_ARCH for 32bit core2 (and corei7 and atom) builds. In most cases, i586 and i686 are equivalent values for TARGET_ARCH, however one important exception is glibc. When configured for i686, glibc enables optimised string functions (SSE, SSE2, etc), which are not used when building for i586. The benefits of i686 optimised string functions vary depending on the application and the CPU, however in some cases the improvements are significant. In one test, a 50% increase in FPS was seen when running the 'smashcat' benchmark [1] in a qtwebkit browser on an Intel Atom based SoC. The gain seems to comes from a 3x improvement in memcpy performance when copying graphics buffer lines (5120 bytes, or 1280 x 4 bytes/pixel), from the CPU to GPU. Note that very large memcpy's (e.g. 32MB) on the same machine show no particular performance increase between i586 and i686. [1] http://www.smashcat.org/av/canvas_test/ Warning: The change in TARGET_ARCH means that _i586 architecture specific over-rides will no longer take effect. Both oe-core and meta-oe have been updated to replace _i586 over-rides with _x86, however other layers may still need review and updating. (From OE-Core rev: dd09fab685de2eaf04aa5ab60f8220b89c1deae9) Signed-off-by: Andre McCurdy <armccurdy@gmail.com> Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Poky
Poky is an integration of various components to form a complete prepackaged build system and development environment. It features support for building customised embedded device style images. There are reference demo images featuring a X11/Matchbox/GTK themed UI called Sato. The system supports cross-architecture application development using QEMU emulation and a standalone toolchain and SDK with IDE integration.
Additional information on the specifics of hardware that Poky supports is available in README.hardware. Further hardware support can easily be added in the form of layers which extend the systems capabilities in a modular way.
As an integration layer Poky consists of several upstream projects such as BitBake, OpenEmbedded-Core, Yocto documentation and various sources of information e.g. for the hardware support. Poky is in turn a component of the Yocto Project.
The Yocto Project has extensive documentation about the system including a reference manual which can be found at: http://yoctoproject.org/documentation
OpenEmbedded-Core is a layer containing the core metadata for current versions of OpenEmbedded. It is distro-less (can build a functional image with DISTRO = "nodistro") and contains only emulated machine support.
For information about OpenEmbedded, see the OpenEmbedded website: http://www.openembedded.org/
Where to Send Patches
As Poky is an integration repository (built using a tool called combo-layer), patches against the various components should be sent to their respective upstreams:
bitbake: Git repository: http://git.openembedded.org/bitbake/ Mailing list: bitbake-devel@lists.openembedded.org
documentation: Git repository: http://git.yoctoproject.org/cgit/cgit.cgi/yocto-docs/ Mailing list: yocto@yoctoproject.org
meta-yocto(-bsp): Git repository: http://git.yoctoproject.org/cgit/cgit.cgi/meta-yocto(-bsp) Mailing list: poky@yoctoproject.org
Everything else should be sent to the OpenEmbedded Core mailing list. If in doubt, check the oe-core git repository for the content you intend to modify. Before sending, be sure the patches apply cleanly to the current oe-core git repository.
Git repository: http://git.openembedded.org/openembedded-core/
Mailing list: openembedded-core@lists.openembedded.org
Note: The scripts directory should be treated with extra care as it is a mix of oe-core and poky-specific files.