process: do not poll join() in MultiprocessingProcesss #1452
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Based on the initial analysis of Esteve Varela Colominas, the polling
on join() with the fixed 100ms delay incurs a significant performance
penalty, especially for short-lived processes. And since portage is
prone to spawning many of those, the penalty adds up easily.
Instead of pooling proc.join() with a fixed 100ms delay, we now use
the blocking variant of join() started in an executor which we await
in the coroutine.
Before this change:
( cd lib; python3 -m timeit 'import portage.process; portage.process.spawn("true")' )
2 loops, best of 5: 104 msec per loop
After this change:
( cd lib; python3 -m timeit 'import portage.process; portage.process.spawn("true")' )
50 loops, best of 5: 4.45 msec per loop
Bug: https://bugs.gentoo.org/958635
Signed-off-by: Florian Schmaus <[email protected]>
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That was... deceptively simple. I have no idea where you found this option 😅 |
This was only possible because of your analysis. So thanks to you as well. :) |
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Based on the initial analysis of Esteve Varela Colominas, the polling on join() with the fixed 100ms delay incurs a significant performance penalty, especially for short-lived processes. And since portage is prone to spawning many of those, the penalty adds up easily.
Instead of pooling proc.join() with a fixed 100ms delay, we now use the blocking variant of join() started in an executor which we await in the coroutine.
Before this change:
After this change:
Bug: https://bugs.gentoo.org/958635