[Bug 254040] AMD 5950X hyperthreading strange performance swings

From: <bugzilla-noreply_at_freebsd.org>
Date: Tue, 21 Dec 2021 10:49:12 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=254040

--- Comment #4 from Andriy Gapon <avg@FreeBSD.org> ---
(In reply to Stefan E├čer from comment #3)
Thank you for the tests!

Another observation is that if your t function is modified to pin bzip2
processes to CPUs (e.g. cpuset -l $((2 * i)) bzip2 ...), then the results are
much more consistent.  In fact, they match the best results from the original
test:
$ ~/test.sh 4         
1048576000 bytes transferred in 4.903489 secs (213842854 bytes/sec)
1048576000 bytes transferred in 4.904297 secs (213807597 bytes/sec)
1048576000 bytes transferred in 4.908786 secs (213612071 bytes/sec)
1048576000 bytes transferred in 4.915402 secs (213324567 bytes/sec)

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