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. > > If we have an event that produce only auxiliary events > (MMAP|COMM|EXIT|FORK), the poll call does not follow > the perf_events_attr wakeup_events setup and reports > no data. > > Fixing this by moving the perf_events_attr::wakeup_events > checking logic into the function and calling it from > perf_output_end. This way any output event is checked > properly. >
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 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? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
