Re: perf: perf sched lat segfault - bisected

Stephane Eranian
2013-10-08T10:25:19Z

Mike,

Ok, I missed the sched record, let me track this down.
Note that there was a second commit to fix this one
by Arnaldo. Do you also have it in your kernel?

51131c4 perf: Fix up MMAP2 buffer space reservation

I will try to reproduce your problem ASAP.

On Tue, Oct 8, 2013 at 12:20 PM, Mike Galbraith <bitbucket@online.de> wrote:
> On Tue, 2013-10-08 at 12:14 +0200, Mike Galbraith wrote:
>> On Tue, 2013-10-08 at 11:23 +0200, Stephane Eranian wrote:
>> > On Tue, Oct 8, 2013 at 10:41 AM, Mike Galbraith <bitbucket@online.de> wrote:
>> > > Box: Q6600
>> > >
>> > > Reproducer:
>> > > perf sched record -- sleep 1
>> > > perf sched lat (boom)
>> > >
>> > I don't understand the test case here.
>> > If I do this, perf sched lat complains of no trace records
>> > and no kernel crash. Could you provide the full cmdline?
>>
>> Hm. That was it, just like so.
>>
>> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf # ./perf sched record -- sleep 1
>> [ perf record: Woken up 1 times to write data ]
>> [ perf record: Captured and wrote 0.763 MB perf.data (~33348 samples) ]
>> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf # ./perf sched lat
>> Segmentation fault
>> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf #
>
> commit 72f3bdf7fd1003373b454bf923d3a196bbc36600
> Author: Mike Galbraith <mgalbraith@suse.de>
> Date: Tue Oct 8 12:18:37 2013 +0200
>
> Revert "perf tools: Add attr->mmap2 support"
>
> This reverts commit 5c5e854bc760a2e2c878df3cfcf2afa4febcd511.
>
> commit a8af8531d08d3edb37a7d67d1a4dc2e1f2f4da58
> Author: Mike Galbraith <mgalbraith@suse.de>
> Date: Tue Oct 8 12:18:23 2013 +0200
>
> Revert "perf trace: Add mmap2 handler"
>
> This reverts commit 384c671e33a7ddf905f2c60b433b9883f0e5a605.
>
> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf # ./perf sched
> record -- sleep 1
> [ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 0.647 MB perf.data (~28289 samples) ]
> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf # perf sched lat
> marge:/usr/local/src/kernel/linux-3.x.git/tools/perf #
>
> (emitted this)
>
> ---------------------------------------------------------------------------------------------------------------
> Task | Runtime ms | Switches | Average delay ms | Maximum delay ms | Maximum delay at |
> ---------------------------------------------------------------------------------------------------------------
> kworker/3:2:383 | 0.073 ms | 1 | avg: 0.020 ms | max: 0.020 ms | max at: 7197.856052 s
> sleep:24717 | 1.163 ms | 3 | avg: 0.011 ms | max: 0.022 ms | max at: 7196.884445 s
> kworker/2:1:36 | 0.097 ms | 1 | avg: 0.007 ms | max: 0.007 ms | max at: 7197.796023 s
> haveged:3547 | 0.023 ms | 2 | avg: 0.006 ms | max: 0.009 ms | max at: 7197.796345 s
> rcu_sched:9 | 0.126 ms | 14 | avg: 0.006 ms | max: 0.021 ms | max at: 7196.897051 s
> ntpd:4185 | 0.034 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7197.746409 s
> kded4:4594 | 0.058 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7197.422130 s
> evolution:15686 | 0.065 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7196.915715 s
> pickup:21579 | 0.062 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7197.329185 s
> JS Watchdog:20053 | 0.020 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7197.623752 s
> perf:24716 | 3.330 ms | 1 | avg: 0.004 ms | max: 0.004 ms | max at: 7197.885690 s
> plasma-desktop:4685 | 1.632 ms | 2 | avg: 0.004 ms | max: 0.005 ms | max at: 7196.933762 s
> master:4307 | 0.104 ms | 2 | avg: 0.004 ms | max: 0.005 ms | max at: 7197.329136 s
> Xorg:4331 | 0.485 ms | 4 | avg: 0.003 ms | max: 0.005 ms | max at: 7197.010801 s
> ksoftirqd/2:18 | 0.014 ms | 1 | avg: 0.003 ms | max: 0.003 ms | max at: 7196.897039 s
> alsa-sink:5282 | 0.000 ms | 200 | avg: 0.003 ms | max: 0.003 ms | max at: 7196.905149 s
> migration/3:22 | 0.000 ms | 1 | avg: 0.002 ms | max: 0.002 ms | max at: 7196.884423 s
> -----------------------------------------------------------------------------------------
> TOTAL: | 7.285 ms | 237 |
> ---------------------------------------------------
>