Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is specified

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is specified
Date	2017-05-19 14:40 +0200
Message-ID	<tIPmi-2aO-11@gated-at.bofh.it> (permalink)
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On Fri, May 19, 2017 at 08:24:19PM +0800, Jin, Yao wrote:
> > Ah, I was more thinking of something like PERF_PMU_CAP_NO_SKID or
> > something that would skip the test and preserve current behaviour.
> 
> OK, I understand now. For example, for PEBS event, its capabilities should
> be set with PERF_PMU_CAP_NO_SKID.

Except you cannot in fact do that, since PEBS is the same struct pmu as
the normal counters (they share counter space after all).

Also, weren't there PEBS errata that would allow this to happen?

But no, more for other architectures to opt out for some reason. But I'm
thinking we want to start out by unconditionally doing this. It would be
good to try and Cc most arch pmu maintainers on this though, so they can
object.

Thread

[PATCH] perf/x86/intel: Drop kernel samples even though :u is specified Jin Yao <yao.jin@linux.intel.com> - 2017-05-19 04:30 +0200
  Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Peter Zijlstra <peterz@infradead.org> - 2017-05-19 11:30 +0200
    Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Will Deacon <will.deacon@arm.com> - 2017-05-19 11:50 +0200
    Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified "Jin, Yao" <yao.jin@linux.intel.com> - 2017-05-19 14:10 +0200
      Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Peter Zijlstra <peterz@infradead.org> - 2017-05-19 14:20 +0200
        Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified "Jin, Yao" <yao.jin@linux.intel.com> - 2017-05-19 14:30 +0200
          Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Peter Zijlstra <peterz@infradead.org> - 2017-05-19 14:40 +0200
            Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified "Jin, Yao" <yao.jin@linux.intel.com> - 2017-05-19 15:40 +0200
              Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified "Jin, Yao" <yao.jin@linux.intel.com> - 2017-05-22 04:20 +0200
                Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Mark Rutland <mark.rutland@arm.com> - 2017-05-22 10:50 +0200
                Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified Peter Zijlstra <peterz@infradead.org> - 2017-05-22 11:30 +0200
                Re: [PATCH] perf/x86/intel: Drop kernel samples even though :u is  specified "Jin, Yao" <yao.jin@linux.intel.com> - 2017-05-22 14:40 +0200

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