6b2cdc4b96
We're seeing huge slowdowns on large builds on the autobuilder. A qemux86 world build was running really slowly, a primary feature was lots of rehashing going on due to an sstate change which caused a rebuild when all output should be identical. This was traced to the hundreds of thousands of calls to get_unihash() from get_taskash(). If we simplify the unitaskhashes data structure, we can bypass the function call and access the data directly. In local profile charts, this significanly sped up process_possible_migrations(), both on profiles and visually. Whilst this change doesn't aid readability, it does solve an otherwise huge performance issue. (Bitbake rev: c4b8440f730c33eaf9f818b856ae81b2f1017fec) Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Bitbake
BitBake is a generic task execution engine that allows shell and Python tasks to be run efficiently and in parallel while working within complex inter-task dependency constraints. One of BitBake's main users, OpenEmbedded, takes this core and builds embedded Linux software stacks using a task-oriented approach.
For information about Bitbake, see the OpenEmbedded website: http://www.openembedded.org/
Bitbake plain documentation can be found under the doc directory or its integrated html version at the Yocto Project website: http://yoctoproject.org/documentation
Contributing
Please refer to http://www.openembedded.org/wiki/How_to_submit_a_patch_to_OpenEmbedded for guidelines on how to submit patches, just note that the latter documentation is intended for OpenEmbedded (and its core) not bitbake patches (bitbake-devel@lists.openembedded.org) but in general main guidelines apply. Once the commit(s) have been created, the way to send the patch is through git-send-email. For example, to send the last commit (HEAD) on current branch, type:
git send-email -M -1 --to bitbake-devel@lists.openembedded.org
Mailing list:
http://lists.openembedded.org/mailman/listinfo/bitbake-devel
Source code:
http://git.openembedded.org/bitbake/