2022-02-22 04:57:12

by German Gomez

Subject: [PATCH] perf arm-spe: Use advertised caps/min_interval as default sample_period

When recording SPE traces, the default sample_period is currently being
set to 1 in the perf_event_attr fields, instead of the value advertised
in '/sys/devices/arm_spe_0/caps/min_interval':

Before:

$ perf record -e arm_spe// -vv -- sleep 1
[...]
{ sample_period, sample_freq } 1
[...]

Use the value from the above sysfs location as a more sensible default
(it was already being read, but the value not being used)

After:

$ perf record -e arm_spe// -vv -- sleep 1
[...]
{ sample_period, sample_freq } 1024
[...]

Signed-off-by: German Gomez <[email protected]>
---
tools/perf/arch/arm64/util/arm-spe.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
index 2100d46cc..5860bbaea 100644
--- a/tools/perf/arch/arm64/util/arm-spe.c
+++ b/tools/perf/arch/arm64/util/arm-spe.c
@@ -158,7 +158,7 @@ static int arm_spe_recording_options(struct auxtrace_record *itr,
return -EINVAL;
}
evsel->core.attr.freq = 0;
- evsel->core.attr.sample_period = 1;
+ evsel->core.attr.sample_period = arm_spe_pmu->default_config->sample_period;
arm_spe_evsel = evsel;
opts->full_auxtrace = true;
}
--
2.25.1

2022-02-23 11:40:38

by Arnaldo Carvalho de Melo

Subject: Re: [PATCH] perf arm-spe: Use advertised caps/min_interval as default sample_period

Em Wed, Feb 23, 2022 at 09:14:36AM +0800, Leo Yan escreveu:
> On Mon, Feb 21, 2022 at 05:10:42PM +0000, German Gomez wrote:
> > When recording SPE traces, the default sample_period is currently being
> > set to 1 in the perf_event_attr fields, instead of the value advertised
> > in '/sys/devices/arm_spe_0/caps/min_interval':
> >
> > Before:
> >
> > $ perf record -e arm_spe// -vv -- sleep 1
> > [...]
> > { sample_period, sample_freq } 1
> > [...]
> >
> > Use the value from the above sysfs location as a more sensible default
> > (it was already being read, but the value not being used)
> >
> > After:
> >
> > $ perf record -e arm_spe// -vv -- sleep 1
> > [...]
> > { sample_period, sample_freq } 1024
> > [...]
> >
> > Signed-off-by: German Gomez <[email protected]>
>
> The change looks good to me:
>
> Reviewed-by: Leo Yan <[email protected]>

Thanks, applied.

- Arnaldo

2022-02-23 13:20:24

by Leo Yan

Subject: Re: [PATCH] perf arm-spe: Use advertised caps/min_interval as default sample_period

On Mon, Feb 21, 2022 at 05:10:42PM +0000, German Gomez wrote:
> When recording SPE traces, the default sample_period is currently being
> set to 1 in the perf_event_attr fields, instead of the value advertised
> in '/sys/devices/arm_spe_0/caps/min_interval':
>
> Before:
>
> $ perf record -e arm_spe// -vv -- sleep 1
> [...]
> { sample_period, sample_freq } 1
> [...]
>
> Use the value from the above sysfs location as a more sensible default
> (it was already being read, but the value not being used)
>
> After:
>
> $ perf record -e arm_spe// -vv -- sleep 1
> [...]
> { sample_period, sample_freq } 1024
> [...]
>
> Signed-off-by: German Gomez <[email protected]>

The change looks good to me:

Reviewed-by: Leo Yan <[email protected]>