Messages in this thread | | | From | "Lofstedt, Marta" <> | Subject | RE: [PATCH 0/9] sched_clock fixes | Date | Wed, 26 Apr 2017 06:41:58 +0000 |
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For bisecting the regression we ran 14 test for 50 repetitions.
Before the bisected regression:
commit 7b09cc5a9debc86c903c2eff8f8a1fdef773c649 Author: Pavel Tatashin <pasha.tatashin@oracle.com> Date: Wed Mar 22 16:24:17 2017 -0400
sched/clock: Fix broken stable to unstable transfer
there was ~0 failing test on the Core2 machine. After regression ~350 failing tests. With your patch-set ~15 failing tests.
To be honest, I must say that these test used to give unstable results on the Core2. But some time ago, the results magically stabilized at ~0 fails, by timing related fixes for other issues. Ville Syrjala now has a patch-set that we believe really solves the graphics parts of the issue. However, I believe that your patch-set still improves the situation related to the tsc instability of the Core2.
/Marta
> -----Original Message----- > From: Peter Zijlstra [mailto:peterz@infradead.org] > Sent: Tuesday, April 25, 2017 4:45 PM > To: Lofstedt, Marta <marta.lofstedt@intel.com> > Cc: tglx@linutronix.de; mingo@kernel.org; linux-kernel@vger.kernel.org; > ville.syrjala@linux.intel.com; daniel.lezcano@linaro.org; Wysocki, Rafael J > <rafael.j.wysocki@intel.com>; martin.peres@linux.intel.com; > pasha.tatashin@oracle.com; daniel.vetter@ffwll.ch > Subject: Re: [PATCH 0/9] sched_clock fixes > > On Tue, Apr 25, 2017 at 09:31:40AM +0000, Lofstedt, Marta wrote: > > Hi Peterz, > > > > I tested your patch-set on the same Core2 machine as where we > discovered the regression. > > With the tsc=unstable boot param that passrate has improved significantly; > 350 fails -> 15 fails. > > So is that the same as before, or still worse? I don't really have a handle on > what your benchmark is here, nor what how 'good' is defined. > > If its still worse than before, I'm completely confused. Because with > "tsc=unstable" the patch you fingered is a complete no-op (__gtod_offset > == 0).
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