Messages in this thread | | | Date | Tue, 23 Jun 2009 16:51:27 +0200 | From | Ingo Molnar <> | Subject | Re: [perf] howto switch from pfmon |
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* Brice Goglin <Brice.Goglin@inria.fr> wrote:
> Ingo Molnar wrote: > > You can also do a profile with such events: > > > > perf record -f -e r1000ffe0 ./hackbench 10 > > > > and look at it via 'perf report'. > > > > I am not sure what the perf.data profile file contains but 'perf > report' only shows percentages. Is there a way to get a 'perf > stat'-like output from 'perf report'? Or maybe just have a -f > option in 'perf stat' to send the output into a file (with the PID > in the name).
It's not yet possible but it's a very good feature request.
> By the way, there's a typo in the description in > tools/perf/Documentation/perf-report.txt, you want s/via perf > report/via perf record/
thanks, fixed and pushed out. You can generally find the latest 'perf' stuff at:
http://people.redhat.com/mingo/tip.git/README
> > [ Note, there's no need to specify any --follow-* flags as that is > > implicit in 'perf'. (and you'll probably also notice that perf > > stat is a lot faster at following fast-forking or > > context-switching workloads than is pfmon, because it's not ptrace > > based.) ] > > What about threads? I didn't find any way to get per-thread > counters. > > Ideally, I'd like to be able to see no perf-related output on > stdout/stderr at runtime, and later have a look at per-thread > counters like 'perf stat' does at runtime.
That's not possible yet either, but makes a lot of sense.
How many threads does your workload typically run, and how do you get their stats displayed?
Per thread info is currently available in the profile output:
perf report --sort comm,pid,symbol
But it would be nice to either extend perf report with a --stat option:
perf report --stat
or to extend perf stat to take an input file via -i:
perf stat -i perf.data
Ingo
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