Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > linux.kernel > #1336703
| From | Oleg Nesterov <oleg@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) |
| Date | 2016-02-17 20:40 +0100 |
| Message-ID | <r3g78-2uR-13@gated-at.bofh.it> (permalink) |
| References | <r3186-vI-11@gated-at.bofh.it> <r3186-vI-13@gated-at.bofh.it> <r3186-vI-9@gated-at.bofh.it> <r36Ku-4qr-35@gated-at.bofh.it> <r37wR-51u-7@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On 02/17, Peter Zijlstra wrote: > > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -3173,6 +3173,10 @@ static void perf_event_enable_on_exec(in > > cpuctx = __get_cpu_context(ctx); > perf_ctx_lock(cpuctx, ctx); > + > + update_context_time(ctx); > + update_cgrp_time_from_cpuctx(cpuctx); > + Even if I don't really understand this change I agree, probably we need to update the counters for enable_on_exec events somehow. But I don't see how this change can make total_time_running == total_time_enabled. And probably this is fine. In fact I do not understand why they should be equal. I inserted printf() into perf_counts_values__scale() to verify that /usr/bin/perf always sees count->run < count->ena even if I do, say, # perf stat -x- -e module:module_load -a sleep 1 0--module:module_load-1007397333-100.00 the kernel reports run=1007397333 ena=1007397573. Close but not equal. Again, I do not think this is wrong, I am only saying that I don't understand this logic because this always means "scaled" for perf. Nevermind, I never looked into tools/perf before, most probably I simply do not understand it at all. Oleg.
Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Oleg Nesterov <oleg@redhat.com> - 2016-02-17 04:40 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Jiri Olsa <jolsa@redhat.com> - 2016-02-17 10:40 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Peter Zijlstra <peterz@infradead.org> - 2016-02-17 11:30 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Jiri Olsa <jolsa@redhat.com> - 2016-02-17 15:50 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Peter Zijlstra <peterz@infradead.org> - 2016-02-17 16:00 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Oleg Nesterov <oleg@redhat.com> - 2016-02-17 20:40 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Peter Zijlstra <peterz@infradead.org> - 2016-02-17 20:50 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Peter Zijlstra <peterz@infradead.org> - 2016-02-17 11:30 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Jiri Olsa <jolsa@redhat.com> - 2016-02-17 11:40 +0100
Re: perf: wrong event->count report (Was: perf basic-test-aarch64 failures) Oleg Nesterov <oleg@redhat.com> - 2016-02-17 20:20 +0100
csiph-web