Messages in this thread | | | Date | Mon, 27 Feb 2012 18:52:25 +0100 | Subject | Re: [PATCH] perf tools: fix guest mode monitoring on AMD | From | Stephane Eranian <> |
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On Mon, Feb 27, 2012 at 6:47 PM, David Ahern <dsahern@gmail.com> wrote: > On 2/27/12 10:33 AM, Stephane Eranian wrote: >> >> Commit: >> >> 1aed267 perf kvm: Do guest-only counting by default >> >> introduced a bug on AMD systems whereby simple commands: >> >> $ perf stat ls >> Performance counter stats for 'ls': >> 0 cycles # 0.000 GHz >> 0.003704596 seconds time elapsed >> >> would not count anything anymore. Same results for perf record. >> >> I tracked it down to guest mode exclusion being enabled >> by default leading to attr->exclude_guest = 1. When >> not operating under any sort of virtualization, this >> causes the PMU not to count anything. >> >> The fix disables guest exclusion by default. >> >> Signed-off-by: Stephane Eranian<eranian@google.com> >> --- >> >> diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c >> index 8109a90..c1017b3 100644 >> --- a/tools/perf/util/util.c >> +++ b/tools/perf/util/util.c >> @@ -6,7 +6,7 @@ >> * XXX We need to find a better place for these things... >> */ >> bool perf_host = true; >> -bool perf_guest = false; >> +bool perf_guest = true; > > > This was recently reverted to false by > c4a7dca92bbb9881a5d678720f1d0c2153499749 > > See: https://lkml.org/lkml/2012/2/8/234 > Yeah, but that causes simple commands such as "perf stat -e cycles ls" to return 0 count.
So either you get a segfault or you get zero count. There is something else going on here...
> David > >> >> void event_attr_init(struct perf_event_attr *attr) >> { >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> Please read the FAQ at http://www.tux.org/lkml/ > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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