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Date: Tue, 6 Jul 2021 21:54:15 +0200
From: Jiri Olsa <jolsa@...hat.com>
To: "Jin, Yao" <yao.jin@...ux.intel.com>
Cc: acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
mingo@...hat.com, alexander.shishkin@...ux.intel.com,
Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v3] perf stat: Disable NMI watchdog message on hybrid
On Tue, Jul 06, 2021 at 10:19:47AM +0800, Jin, Yao wrote:
> Hi Jiri,
>
> On 6/10/2021 11:45 AM, Jin Yao wrote:
> > If we run a single workload that only runs on big core, there is always a
> > ugly message about disabling the NMI watchdog because the atom is not
> > counted.
> >
> > Before:
> >
> > # ./perf stat true
> >
> > Performance counter stats for 'true':
> >
> > 0.43 msec task-clock # 0.396 CPUs utilized
> > 0 context-switches # 0.000 /sec
> > 0 cpu-migrations # 0.000 /sec
> > 45 page-faults # 103.918 K/sec
> > 639,634 cpu_core/cycles/ # 1.477 G/sec
> > <not counted> cpu_atom/cycles/ (0.00%)
> > 643,498 cpu_core/instructions/ # 1.486 G/sec
> > <not counted> cpu_atom/instructions/ (0.00%)
> > 123,715 cpu_core/branches/ # 285.694 M/sec
> > <not counted> cpu_atom/branches/ (0.00%)
> > 4,094 cpu_core/branch-misses/ # 9.454 M/sec
> > <not counted> cpu_atom/branch-misses/ (0.00%)
> >
> > 0.001092407 seconds time elapsed
> >
> > 0.001144000 seconds user
> > 0.000000000 seconds sys
> >
> > Some events weren't counted. Try disabling the NMI watchdog:
> > echo 0 > /proc/sys/kernel/nmi_watchdog
> > perf stat ...
> > echo 1 > /proc/sys/kernel/nmi_watchdog
> >
> > # ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
> >
> > Performance counter stats for 'true':
> >
> > <not counted> cpu_atom/cycles/ (0.00%)
> > <not counted> msr/tsc/ (0.00%)
> >
> > 0.001904106 seconds time elapsed
> >
> > 0.001947000 seconds user
> > 0.000000000 seconds sys
> >
> > Some events weren't counted. Try disabling the NMI watchdog:
> > echo 0 > /proc/sys/kernel/nmi_watchdog
> > perf stat ...
> > echo 1 > /proc/sys/kernel/nmi_watchdog
> > The events in group usually have to be from the same PMU. Try reorganizing the group.
> >
> > Now we disable the NMI watchdog message on hybrid, otherwise there
> > are too many false positives.
> >
> > After:
> >
> > # ./perf stat true
> >
> > Performance counter stats for 'true':
> >
> > 0.79 msec task-clock # 0.419 CPUs utilized
> > 0 context-switches # 0.000 /sec
> > 0 cpu-migrations # 0.000 /sec
> > 48 page-faults # 60.889 K/sec
> > 777,692 cpu_core/cycles/ # 986.519 M/sec
> > <not counted> cpu_atom/cycles/ (0.00%)
> > 669,147 cpu_core/instructions/ # 848.828 M/sec
> > <not counted> cpu_atom/instructions/ (0.00%)
> > 128,635 cpu_core/branches/ # 163.176 M/sec
> > <not counted> cpu_atom/branches/ (0.00%)
> > 4,089 cpu_core/branch-misses/ # 5.187 M/sec
> > <not counted> cpu_atom/branch-misses/ (0.00%)
> >
> > 0.001880649 seconds time elapsed
> >
> > 0.001935000 seconds user
> > 0.000000000 seconds sys
> >
> > # ./perf stat -e '{cpu_atom/cycles/,msr/tsc/}' true
> >
> > Performance counter stats for 'true':
> >
> > <not counted> cpu_atom/cycles/ (0.00%)
> > <not counted> msr/tsc/ (0.00%)
> >
> > 0.000963319 seconds time elapsed
> >
> > 0.000999000 seconds user
> > 0.000000000 seconds sys
> >
> > Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> > ---
> > v3:
> > - Use evlist__has_hybrid() to check there is at least one hybrid
> > event in evlist.
> >
> > v2:
> > - If the group was mixed with hybrid event and non-hybrid event,
> > the NMI watchdog message was still reported. V2 adds checking
> > for hybrid event mixed group.
Acked-by: Jiri Olsa <jolsa@...hat.com>
thanks,
jirka
> >
> > tools/perf/util/stat-display.c | 9 ++++++---
> > 1 file changed, 6 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/stat-display.c b/tools/perf/util/stat-display.c
> > index b759dfd633b4..55ae0d1705a9 100644
> > --- a/tools/perf/util/stat-display.c
> > +++ b/tools/perf/util/stat-display.c
> > @@ -19,6 +19,7 @@
> > #include "util.h"
> > #include "iostat.h"
> > #include "pmu-hybrid.h"
> > +#include "evlist-hybrid.h"
> > #define CNTR_NOT_SUPPORTED "<not supported>"
> > #define CNTR_NOT_COUNTED "<not counted>"
> > @@ -465,9 +466,11 @@ static void printout(struct perf_stat_config *config, struct aggr_cpu_id id, int
> > config->csv_sep);
> > if (counter->supported) {
> > - config->print_free_counters_hint = 1;
> > - if (is_mixed_hw_group(counter))
> > - config->print_mixed_hw_group_error = 1;
> > + if (!evlist__has_hybrid(counter->evlist)) {
> > + config->print_free_counters_hint = 1;
> > + if (is_mixed_hw_group(counter))
> > + config->print_mixed_hw_group_error = 1;
> > + }
> > }
> > fprintf(config->output, "%-*s%s",
> >
>
> Any comments for v3?
>
> Thanks
> Jin Yao
>
>
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