Hi Sebastian
Am Freitag, 12. Februar 2016, 10:07:59 schrieben Sie:
...
> What about rt4? It is only the stable update so you should see here the
> numbers from rt3. If that is true and your numbers are stable it should
> be easy to run git bisect between rt4 and rt5. And looking at
> https://git.kernel.org/rt/linux-rt-devel/h/v4.4.1-rt5
> the only non-cosmetic change in -rt5 that should affect you is the
> migrate-disable fixup from Mike.
I have done a bisect run, its a rather innocent looking on liner which seems
to cause the problems. The numbers where reasonably stable so i am pretty
confident that this is the patch giving ~26µs additional latency on the Altera
SOC plattform:
eec2bf477ac674583a7d73b9d00f47c528b7266d is the first bad commit
commit eec2bf477ac674583a7d73b9d00f47c528b7266d
Author: Sebastian Andrzej Siewior <bige...@linutronix.de>
Date: Thu Feb 4 16:38:10 2016 +0100
kernel/perf: mark perf_cpu_context's timer as irqsafe
Otherwise we get a WARN_ON() backtrace and some events are reported as
"not counted".
Cc: stable...@vger.kernel.org
Reported-by: Yang Shi <yang....@linaro.org>
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
Here are the numbers of the bisect run for reference:
==> g0dd3bdd <==
# Total: 100000000 099999829
# Min Latencies: 00010 00010
# Avg Latencies: 00020 00021
# Max Latencies: 00084 00101
# Histogram Overflows: 00000 00000
==> gbbc7819 <==
# Total: 100000000 099999798
# Min Latencies: 00010 00010
# Avg Latencies: 00021 00021
# Max Latencies: 00086 00091
# Histogram Overflows: 00000 00000
==> geec2bf4 <==
# Total: 099998713 100000000
# Min Latencies: 00010 00010
# Avg Latencies: 00020 00021
# Max Latencies: 00113 00070
# Histogram Overflows: 00000 00000
Best Regards
Tim
