Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 30 May 2013 14:51:13 +0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH 1/2] perf: Enable wakeup_events logic for all events |
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Em Thu, May 30, 2013 at 01:02:39PM +0200, Peter Zijlstra escreveu: > On Thu, May 30, 2013 at 11:53:06AM +0200, Jiri Olsa wrote: > > Currently the perf_events_attr::wakeup_events logic is > > checked only for regular samples.
> So something like this came up before and ISTR doing a patch similar to > what you propose but ended up not going with it because... uhm...
> I have vague memories about people (possibly me) wanting wake_events to > mean samples. Like get me a wakeup every 20 samples. With your patch the > side-band events now also count towards 'events'.
I think it was me, and the test case is tools/perf/pythoh/twatch.py, that just wants those side band events, the "fix" was:
commit cfeb1d90a1b1db96383b48888cb7a5f10ca12e12 Author: Arnaldo Carvalho de Melo <acme@redhat.com> Date: Mon Jan 30 14:43:21 2012 -0200
perf python: Use attr.watermark in twatch.py We want to be woken up for every PERF_RECORD_ event, attr.wakeup_events is only for PERF_RECORD_SAMPLE, so also use attr.watermark = 1 to fix that. > I think the most common use of wake_events is people setting it to 1 and > have perf generate a SIGfoo for every sample so they can do magic in > their userspace signal handler. This is popular for interpreters. > > It would be unfortunate to get SIGfoos for side-band chatter. > > > Makes sense?
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