Richard Purdie 08aa69a1fd bitbake: runqueue: Add support for BB_LOADFACTOR_MAX
Some ditros don't enable /proc/pressure and it tends to be those which we
see bitbake timeout issues on, seemingly as load gets too high and the bitbake
processes don't get scheduled in for minutes at a time.

Add support for stopping running extra tasks if the system load average goes
above a certain threshold by setting BB_LOADFACTOR_MAX.

The value used is scaled by CPU number, so a value of 1 would be when
the load average equals the number of cpu cores of the system, under one
only starts tasks when the load average is below the number of cores.

This means you can centrally set a value such as 1.5 which will then
scale correctly to different sized machines with differing numbers
of CPUs.

The pressure regulation is probably more accurate and responsive, however
our graphs do show singificant load spikes on some workers and this
patch is aimed at trying to avoid those.

Pressure regulation is used where available in preference to this load
factor regulation when both are set.

(Bitbake rev: 14a27306f6dceb4999c2804ccae5a09cc3d8dd49)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
2024-02-23 14:34:05 +00:00
2024-02-19 11:34:33 +00:00
2021-07-19 18:07:21 +01:00
2023-10-19 11:31:13 +01:00

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

Please refer to our contributor guide here: https://docs.yoctoproject.org/dev/contributor-guide/ for full details on how to submit changes.

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/):

BitBake (files in bitbake/):

Documentation (files in documentation/):

meta-yocto (files in meta-poky/, meta-yocto-bsp/):

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.

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