Re: [PATCH 4/4] perf, x86: Fix event scheduler to solve complexscheduling problems

From: Peter Zijlstra
Date: Sat Apr 16 2011 - 06:16:17 EST


On Sat, 2011-04-16 at 12:14 +0200, Ingo Molnar wrote:
> * Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> > On Sat, 2011-04-16 at 11:43 +0200, Ingo Molnar wrote:
> > > I'd also prefer if we first had actual testcases in 'perf test' for all these
> > > failures - it took an *awfully* long time to find these regressions (the event
> > > scheduler code has been committed for months), while with proper testcases it
> > > would only take a second to run 'perf test'.
> >
> > These cases only exist on AMD F15, I don't think there's many people
> > with such systems around.
>
> Well, if the trend continues we'll have more twisted constraints and more bugs
> of this sort, so having a testsuite sure cannot hurt, right?

For sure. But the problem with writing test cases at the perf userspace
level is that they're very hardware specific. It would be much easier to
write unit tests for the solver itself.
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