f431f766a0
When we switched to recipe specific sysroots (rss), performance took a nose dive. Its easy to blame rss but it turns out not to be entirely at fault. Three configurations are compared here: a) Pre-RSS (revision45df694a9f) b) Post-RSS (revision226a508da9) c) as b) with this change Overall build times: a) 22794.25user 2687.88system 30:32.84elapsed 1390%CPU (0avgtext+0avgdata 919056maxresident)k b) 22677.25user 3238.79system 36:16.68elapsed 1190%CPU (0avgtext+0avgdata 918896maxresident)k c) 23571.84user 3383.65system 31:36.83elapsed 1421%CPU (0avgtext+0avgdata 919068maxresident)k For the overall build and sstate directories, du -s shows: a) 3992588 build-pre-rss/sstate-cache 30804484 build-pre-rss/tmp b) 4013272 build-with-rss/sstate-cache 36519084 build-with-rss/tmp c) 4014744 build-with-rss2/sstate-cache 35336960 build-with-rss2/tmp However more worryingly: $ du -s build-pre-rss/tmp/sysroots/ 2506092 build-pre-rss/tmp/sysroots/ $ du -s build-with-rss/tmp/sysroots-components/ 3790712 build-with-rss/tmp/sysroots-components/ $ du -s build-with-rss2/tmp/sysroots-components/ 2467544 build-with-rss2/tmp/sysroots-components/ These numbers *should* be equivalent but as you can see, b) is ~1.2GB larger. The reason turned out to be patchelf. Taking a specific binary from a specific recipe, bc from bc-native, in a) its 82kb (stripped) yet in b) its 2.17MB. $ ./patchelf --set-interpreter /bin/rp bc warning: working around a Linux kernel bug by creating a hole of 2084864 bytes in ‘bc’ https://github.com/NixOS/patchelf/blob/master/src/patchelf.cc#L710 shows that this "hole" is just padded zeros using memset, its not a proper sparse hole. This patch copies files with cp --sparse=always after modifying them with patchelf, then replacing the original file. The better fix will be to fix this in patchself itself and seek() there when writing the new file but that means new uninative tarballs and will take a bit of work so I'm proposing this workaround in the meantime. Also, this patch drops error handling since subprocess check_output() tracebacks will print this information if the command fails so we can simplify the code. 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-poky, 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.