da95ad49d8
TL;DR version:
with this, and the previous compression level changes
I am seeing drastic speedups in package_write_rpm completion times:
webkitgtk goes from 78 seconds to 37 seconds
glibc-locale goes from 399 seconds to 58 seconds (!)
The long version:
rpm uses multithreading for two purposes:
- spawning compressors (which are nowadays themselves
multi-threaded, so the feature is not as useful as it once
was)
- parallel file classification
While the former behaves well on massively parallel CPUs
(it was written and verified here :), the latter was then added
by upstream and only benchmarked on their very old, slow laptop,
apparently:
41f0e214f2
On anything more capable it starts showing pathologic behavior,
presumably from spawning massive amount of very short-lived threads,
and then having to synchronize them. For example classifying glibc-locale
takes
5m20s with 256 threads (default on my machine!)
1m49s with 64 threads
59s with 16 threads
48s with 8 threads
Even a more typical recipe like webkitgtk is affected:
47s with 256 threads
32s with 64 threads
27s with 16 or 8 threads
I have found that the optimal amount is actually four: this also
means that only four compressors are running at a time, but
as they're themselves using threads, and typical recipes are dominated
by just two or three large packages, this does not affect overall
completion time.
(From OE-Core rev: 896192604d84a6f77095f23cd13232e249b7aac5)
Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Poky
Poky is an integration of various components to form a pre-packaged build system and development environment which is used as a development and validation tool by the Yocto Project. It features support for building customised embedded style device images and custom containers. There are reference demo images ranging from X11/GTK+ to Weston, commandline and more. The system supports cross-architecture application development using QEMU emulation and a standalone toolchain and SDK suitable for 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 BSP layers which extend the systems capabilities in a modular way. Many layers are available and can be found through the layer index.
As an integration layer Poky consists of several upstream projects such as BitBake, OpenEmbedded-Core, Yocto documentation, the 'meta-yocto' layer which has configuration and hardware support components. These components are all part of the Yocto Project and OpenEmbedded ecosystems.
The Yocto Project has extensive documentation about the system including a reference manual which can be found at https://docs.yoctoproject.org/
OpenEmbedded is the build architecture used by Poky and the Yocto project. For information about OpenEmbedded, see the OpenEmbedded website.
Contribution Guidelines
The project works using a mailing list patch submission process. Patches should be sent to the mailing list for the repository the components originate from (see below). Throughout the Yocto Project, the README files in the component in question should detail where to send patches, who the maintainers are and where bugs should be reported.
A guide to submitting patches to OpenEmbedded is available at:
https://www.openembedded.org/wiki/How_to_submit_a_patch_to_OpenEmbedded
There is good documentation on how to write/format patches at:
https://www.openembedded.org/wiki/Commit_Patch_Message_Guidelines
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:
OpenEmbedded-Core (files in meta/, meta-selftest/, meta-skeleton/, scripts/):
- Git repository: https://git.openembedded.org/openembedded-core/
- Mailing list: openembedded-core@lists.openembedded.org
BitBake (files in bitbake/):
- Git repository: https://git.openembedded.org/bitbake/
- Mailing list: bitbake-devel@lists.openembedded.org
Documentation (files in documentation/):
- Git repository: https://git.yoctoproject.org/cgit/cgit.cgi/yocto-docs/
- Mailing list: docs@lists.yoctoproject.org
meta-yocto (files in meta-poky/, meta-yocto-bsp/):
- Git repository: https://git.yoctoproject.org/cgit/cgit.cgi/meta-yocto
- Mailing list: poky@lists.yoctoproject.org
If in doubt, check the openembedded-core git repository for the content you intend to modify as most files are from there unless clearly one of the above categories. Before sending, be sure the patches apply cleanly to the current git repository branch in question.