Re: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware

From	Vineet Gupta <Vineet.Gupta1@synopsys.com>
Newsgroups	linux.kernel
Subject	Re: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware
Date	2016-05-12 08:30 +0200
Message-ID	<rxSid-7O-5@gated-at.bofh.it> (permalink)
References	<rwPPr-2FZ-5@gated-at.bofh.it> <rwPPt-2FZ-35@gated-at.bofh.it> <rwTT3-6II-1@gated-at.bofh.it> <rwXal-1D1-73@gated-at.bofh.it> <rxI9b-6rJ-7@gated-at.bofh.it>
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On Thursday 12 May 2016 01:06 AM, Peter Zijlstra wrote:
> On Mon, May 09, 2016 at 10:53:43PM +0530, Vineet Gupta wrote:
> 
>> > Right thats what I feared. But hold on, I don't think we need to change the ABI to
>> > achieve what we want. Gosh why did I even take that path.
>> > 
>> > Currently the errno switch case in perf_evsel__open_strerror() in doesn't handle
>> > ENOTSUPP. So how about we add that - augmented with the same sample_period !0
>> > check to barf for lack of sampling support.
>> > 
>> > Do you see anything wrong with that ?
>
> Should work I think.

Tried that and doesn't even compile. Reconfirms what Vince said, ENOTSUPP is not
exposed to userspace (being in include/linux and not include/uapi/linux)

Thread

[RFC 0/2] report perf sampling failing due to PMU lacking overflow intr support Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-09 11:40 +0200
  [RFC 2/2] perf/core: change errno for sampling event not supported in hardware Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-09 11:40 +0200
    Re: [RFC 2/2] perf/core: change errno for sampling event not supported  in hardware Vince Weaver <vincent.weaver@maine.edu> - 2016-05-09 16:00 +0200
      Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Vineet Gupta <vgupta@synopsys.com> - 2016-05-09 19:30 +0200
        Re: [RFC 2/2] perf/core: change errno for sampling event not supported  in hardware Vince Weaver <vincent.weaver@maine.edu> - 2016-05-11 05:40 +0200
        Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Peter Zijlstra <peterz@infradead.org> - 2016-05-11 21:40 +0200
          Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-12 08:30 +0200
            Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Peter Zijlstra <peterz@infradead.org> - 2016-05-12 08:50 +0200
              Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-12 09:00 +0200
                Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Peter Zijlstra <peterz@infradead.org> - 2016-05-12 09:30 +0200
                Re: [RFC 2/2] perf/core: change errno for sampling event not supported  in hardware Vince Weaver <vincent.weaver@maine.edu> - 2016-05-13 01:10 +0200
                Re: [RFC 2/2] perf/core: change errno for sampling event not  supported in hardware Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-13 10:40 +0200
                [PATCH-REBASED 0/2] report perf sampling failing due to PMU lacking overflow intr support Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-30 13:40 +0200
                [PATCH-REBASED 1/2] tools/perf: Handle EOPNOTSUPP for sampling events Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-30 13:40 +0200
                [PATCH-REBASED 2/2] perf/core: change errno for sampling event not supported in hardware Vineet Gupta <Vineet.Gupta1@synopsys.com> - 2016-05-30 13:40 +0200

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