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Re: [PATCH] perf/x86: fix event counter update issue

From Andi Kleen <ak@linux.intel.com>
Newsgroups linux.kernel
Subject Re: [PATCH] perf/x86: fix event counter update issue
Date 2017-02-22 20:20 +0100
Message-ID <tdKCd-6rR-11@gated-at.bofh.it> (permalink)
References (5 earlier) <sIXm1-4RO-3@gated-at.bofh.it> <sJVBv-3XH-11@gated-at.bofh.it> <sKYGZ-3jJ-19@gated-at.bofh.it> <tdGyD-3dk-37@gated-at.bofh.it> <tdHbj-3Iw-1@gated-at.bofh.it>
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> No. It related to the counter width. The number of bits we can use should be
> 1 bit less than the total width. Otherwise, there will be problem.
> For big cores such as haswell, broadwell, skylake, the counter width is 48 bit.
> So we can only use 47 bits.
> For Silvermont and KNL, the counter width is only 32 bit I think. So we can only
> use 31 bits.

It is 40 bits on these cores, so 39bits.

-Andi

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Thread

Re: [PATCH] perf/x86: fix event counter update issue Vince Weaver <vincent.weaver@maine.edu> - 2017-02-22 16:00 +0100
  RE: [PATCH] perf/x86: fix event counter update issue "Liang, Kan" <kan.liang@intel.com> - 2017-02-22 16:40 +0100
    Re: [PATCH] perf/x86: fix event counter update issue Andi Kleen <ak@linux.intel.com> - 2017-02-22 20:20 +0100
    RE: [PATCH] perf/x86: fix event counter update issue Vince Weaver <vincent.weaver@maine.edu> - 2017-02-23 16:10 +0100
      RE: [PATCH] perf/x86: fix event counter update issue "Liang, Kan" <kan.liang@intel.com> - 2017-02-23 17:20 +0100

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