Re: [LTP] [PATCH v2] sched: starvation: Autocallibrate the timeout

[Cyril Hrubis <chrubis@suse.cz>]

Hi!
> > Instead of hardcoding the values we attempt to measure the CPU speed and
> > set the timeout accordingly. Given that the difference in the duration
> > of the test when the kernel is buggy is about 30x we do not have to have
> > a precise callibration, just very rough estimate if we are running on a
> > server or small ARM board would suffice.
> 
> > So we attempt to measure how long does a bussy loop take and base the
> s/bussy/busy/
> 
> > default timeout on that. On x86_64 CPUs the resulting timeout is about
> > double of the value of the actual test runtime and works fine, but we
> > need to make sure that the coeficient we divide the result from
> > callibrate works for small boards too. So please run the test on as many
> > machines as you can and report if we need to make the dividor smaller or
> > not.
> 
> This looks much better: ppc64le has Timeout per run is 0h 00m 30s (1m 10s
> runtime), others (x68_64, s390x, aarch64) have ~ 1 min or less.
> 
> Tested-by: Petr Vorel <pvorel@suse.cz>

And I've realized that we also have to check if we had exhausted our
runtime in the testcase, because if someone overrides the timeout the
test will stil pass even when it shouldn't. I will send a separate patch
for that.

-- 
Cyril Hrubis
chrubis@suse.cz

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