Re: [GIT PULL rcu-tasks-trace] 50x speedup for synchronize_rcu_tasks_trace()

[Alexei Starovoitov]

On Tue, Sep 22, 2020 at 9:25 AM Paul E. McKenney <paulmck@xxxxxxxxxx> wrote:
>
> Hello, Alexei,
>
> This pull request contains eight commits that speed up RCU Tasks Trace
> grace periods by a factor of 50, fix a few race conditions exposed
> by this speedup, and clean up a couple of minor issues.  These have
> been exposed to 0day and -next testing, and have passed well over 1,000
> hours of rcutorture testing, some of which has contained ad-hoc changes
> to further increase race probabilities.  So they should be solid!
> (Famous last words...)
>
> I would normally have sent this series up through -tip, but as we
> discussed, going up through the BFP and networking trees provides the
> needed exposure to real-world testing of these changes.  Please note
> that the first patch is already in mainline, but given identical SHA-1
> commit IDs, git should have no problem figuring this out.  I will also
> be retaining these commits in -rcu in order to continue exposing them
> to rcutorture testing, but again the identical SHA-1 commit IDs will
> make everything work out.

Pulled into bpf-next. Thanks a lot.

Also confirming 50x speedup.
Really nice to see that selftests/bpf are now fast again.

Not only all bpf developers will be running these patches now,
but the bpf CI system will be exercising them as well.