Re: perf/ftrace: does PERF_EVENT_IOC_SET_FILTER serve any purpose?

From: Arnaldo Carvalho de Melo
Date: Tue Jun 09 2015 - 16:11:47 EST


Em Tue, Jun 09, 2015 at 04:07:01PM -0400, Vince Weaver escreveu:
> On Tue, 9 Jun 2015, Steven Rostedt wrote:
>
> > What kernel are you using? You may need to update perf.
> >
> > We switched to a tracefs filesystem, but the old perf wont read any
> > events if it's not located in debugfs. That is, it actually tested
> > which filesystem the event files were mounted on, and if they didn't
> > match the debugfs mount type, it ignored them. That was fixed recently.
>
> I am running 4.1-rc7 and was trying to use perf_4.0.
>
> If I use the kernel's version of perf it works.
>
> sigh.

Indeed, its always a shame when that happens, I had a similar reaction
when Steven told it was validating the filesystem type, completely
unnecessary, has been there for a long time :-\

Date: Tue Jul 21 12:20:22 2009 -0400

perf_counter: Add tracepoint support to perf list, perf stat

- Arnaldo
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