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SubjectRe: perf-stat per thread results
On 05/14/11 06:49, Wim Heirman wrote:
>> Hmm.... my mileage varies using latest kernel
>> (446cc6345d3de6571bdd0840f48aca441488a28d)
>>
>> $ /tmp/build-perf/perf record --stat -fo /tmp/perf.data -p $(pidof rsyslogd)
>> ^C[ perf record: Woken up 1 times to write data ]
>> [ perf record: Captured and wrote 0.007 MB /tmp/perf.data (~308 samples) ]
>>
>> $ /tmp/build-perf/perf report -T -i /tmp/perf.data
>> # Events: 6 cycles
>> #
>> # Overhead Command Shared Object Symbol
>> # ........ ........ ................. ..........................
>> #
>> 97.61% rsyslogd libc-2.13.so [.] __libc_disable_asynccancel
>> 2.39% rsyslogd [kernel.kallsyms] [k] native_write_msr_safe
>>
>>
>> #
>> # (For a higher level overview, try: perf report --sort comm,dso)
>> #
>> # PID TID
>>
>>
>> ie., I do not get the counter values. Specifying the counter with -e
>> (e.g., -e branch-misses) does not help -- still no counter output.
>
> Is rsyslogd multithreaded? (Or at least, do the non-main threads
> execute any work during your perf-record measurement) If not, then
> what you see is consistent with what I'm getting, i.e. everything but
> the main thread is reported.

It is multithreaded, but my point is that I do not get counter output at
the end -- the PID/TID table is empty. I do not get counters for single
threaded processes nor for commands run by perf record -- e.g.,
/tmp/build-perf/perf record --stat -e instructions -fo /tmp/perf.data --
sleep 1

David


>
> Regards,
> Wim


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