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Groups > linux.kernel > #1293351
| From | Andi Kleen <andi@firstfloor.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat |
| Date | 2015-12-16 22:30 +0100 |
| Message-ID | <qGrO1-76X-9@gated-at.bofh.it> (permalink) |
| References | <qG8BH-3aD-1@gated-at.bofh.it> <qG8BJ-3aD-21@gated-at.bofh.it> <qGlpf-2W2-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
> > +/*
> > + * Check whether we can use a group for top down.
> > + * Without a group may get bad results due to multiplexing.
> > + */
>
> That is not because you have a counter used by the NMI that
> you cannot group. If HT is off you have plenty of counters to
> do this.
Such a heuristic wouldn't work on Atom where there are no more
counters in this case.
> > +static bool check_group(bool *warn)
> > +{
> > + int n;
> > +
> > + if (sysctl__read_int("kernel/nmi_watchdog", &n) < 0)
> > + return false;
> > + if (n > 0) {
> > + *warn = true;
> > + return false;
> > + }
> > + return true;
> > +}
> > +
>
> I do not like this part very much. You are pulling in x86 specific
> knowledge into
> builtin_stat.c. Why not move this into an x86 specific file?
Done.
> > err = parse_events(evsel_list, transaction_attrs, NULL);
> > @@ -1511,6 +1579,36 @@ static int add_default_attributes(void)
> > return 0;
> > }
> >
> > + if (topdown_run) {
> > + char *str = NULL;
> > + bool warn = false;
> > +
> > + filter_events(topdown_attrs, &str, check_group(&warn));
> > + if (topdown_attrs[0] && str) {
> > + if (warn)
> > + fprintf(stderr,
> > + "nmi_watchdog enabled with topdown. May give wrong results.\n"
> > + "Disable with echo 0 > /proc/sys/kernel/nmi_watchdog\n");
>
> This is x86 specific. Why not just try it out and in case of error
> suggest checking
> if pinned system-wide events exist (such as NMI watchdog on x86). that would
> be more generic.
That's really complicated, i would have to tear down all state and then
resubmit all the events. I think just checking the NMI watchdog is good
enough. I couldn't give a sensible error message for the generic case
anyways.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
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Add top down metrics to perf stat v2 Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
[PATCH 07/10] perf, tools, stat: Add extra output of counter values with -v Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
[PATCH 10/10] x86, perf: Add Top Down events to Intel Atom Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
[PATCH 04/10] perf, tools, stat: Scale values by unit before metrics Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
[PATCH 09/10] x86, perf: Add Top Down events to Intel Core Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
[PATCH 03/10] perf, tools, stat: Avoid fractional digits for integer scales Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: [PATCH 03/10] perf, tools, stat: Avoid fractional digits for integer scales Stephane Eranian <eranian@google.com> - 2015-12-16 15:30 +0100
[PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: [PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat Stephane Eranian <eranian@google.com> - 2015-12-16 15:40 +0100
Re: [PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen <andi@firstfloor.org> - 2015-12-16 22:30 +0100
Re: [PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat Stephane Eranian <eranian@google.com> - 2015-12-17 10:30 +0100
Re: [PATCH 05/10] perf, tools, stat: Basic support for TopDown in perf stat Andi Kleen <andi@firstfloor.org> - 2015-12-17 15:10 +0100
[PATCH 08/10] x86, perf: Support sysfs files depending on SMT status Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: [PATCH 08/10] x86, perf: Support sysfs files depending on SMT status Peter Zijlstra <peterz@infradead.org> - 2015-12-16 10:00 +0100
Re: [PATCH 08/10] x86, perf: Support sysfs files depending on SMT status Stephane Eranian <eranian@google.com> - 2015-12-16 13:50 +0100
Re: [PATCH 08/10] x86, perf: Support sysfs files depending on SMT status Andi Kleen <andi@firstfloor.org> - 2015-12-16 17:30 +0100
[PATCH 01/10] perf, tools: Dont stop PMU parsing on alias parse error Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: [PATCH 01/10] perf, tools: Dont stop PMU parsing on alias parse error Jiri Olsa <jolsa@redhat.com> - 2015-12-21 17:10 +0100
[PATCH 02/10] perf, tools, stat: Force --per-core mode for .agg-per-core aliases Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: [PATCH 02/10] perf, tools, stat: Force --per-core mode for .agg-per-core aliases Stephane Eranian <eranian@google.com> - 2015-12-16 15:20 +0100
Re: [PATCH 02/10] perf, tools, stat: Force --per-core mode for .agg-per-core aliases Jiri Olsa <jolsa@redhat.com> - 2015-12-21 17:20 +0100
Re: [PATCH 02/10] perf, tools, stat: Force --per-core mode for .agg-per-core aliases Jiri Olsa <jolsa@redhat.com> - 2015-12-21 17:20 +0100
[PATCH 06/10] perf, tools, stat: Add computation of TopDown formulas Andi Kleen <andi@firstfloor.org> - 2015-12-16 02:00 +0100
Re: Add top down metrics to perf stat v2 Stephane Eranian <eranian@google.com> - 2015-12-17 11:30 +0100
Re: Add top down metrics to perf stat v2 Andi Kleen <andi@firstfloor.org> - 2015-12-17 15:10 +0100
Re: Add top down metrics to perf stat v2 Stephane Eranian <eranian@google.com> - 2015-12-18 00:40 +0100
Re: Add top down metrics to perf stat v2 Andi Kleen <andi@firstfloor.org> - 2015-12-18 03:00 +0100
Re: Add top down metrics to perf stat v2 Stephane Eranian <eranian@google.com> - 2015-12-18 10:40 +0100
Re: Add top down metrics to perf stat v2 Andi Kleen <andi@firstfloor.org> - 2015-12-18 22:40 +0100
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