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@xxxxxxxxx> > AuthorDate: Tue, 31 May 2011 12:26:55 +0200 > Committer: Ingo Molnar <mingo@xxxxxxx> > 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@xxxxxxxxxxxxxxx> > Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> > Link: http://lkml.kernel.org/r/1306835745.2353.3.camel@twins > Signed-off-by: Ingo Molnar <mingo@xxxxxxx> Thanks. -- Regards/Gruss, Boris. Advanced Micro Devices GmbH Einsteinring 24, 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html