Messages in this thread | | | Date | Tue, 31 May 2011 14:56:21 +0200 | From | Borislav Petkov <> | Subject | Re: [tip:sched/urgent] sched: Fix cross-cpu clock sync on remote wakeups |
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Hey Peter,
On Tue, May 31, 2011 at 12:31:20PM +0000, tip-bot for Peter Zijlstra wrote: > Commit-ID: f01114cb59d670e9b4f2c335930dd57db96e9360 > Gitweb: http://git.kernel.org/tip/f01114cb59d670e9b4f2c335930dd57db96e9360 > Author: Peter Zijlstra <a.p.zijlstra@chello.nl> > AuthorDate: Tue, 31 May 2011 12:26:55 +0200 > Committer: Ingo Molnar <mingo@elte.hu> > CommitDate: Tue, 31 May 2011 14:19:56 +0200 > > sched: Fix cross-cpu clock sync on remote wakeups > > Markus reported that commit 317f394160e ("sched: Move the second half > of ttwu() to the remote cpu") caused some accounting funnies on his AMD > Phenom II X4, such as weird 'top' results. > > It turns out that this is due to non-synced TSC
this would mean that his machine doesn't pass the TSC sync check at boot but that's a F10h and they usu. have synchronized TSCs?
I'm confused.
> and the queued remote > wakeups stopped coupeling the two relevant cpu clocks, which leads to > wakeups seeing time jumps, which in turn lead to skewed runtime stats. > > Add an explicit call to sched_clock_cpu() to couple the per-cpu clocks > to restore the normal flow of time. > > Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> > Link: http://lkml.kernel.org/r/1306835745.2353.3.camel@twins > Signed-off-by: Ingo Molnar <mingo@elte.hu>
Thanks.
-- Regards/Gruss, Boris.
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