Re: [PATCH v2] perf stat: enable 1ms interval for printing event counters values

From: Arnaldo Carvalho de Melo
Date: Wed Apr 04 2018 - 09:39:29 EST


Em Wed, Apr 04, 2018 at 09:05:16AM +0200, Jiri Olsa escreveu:
> On Tue, Apr 03, 2018 at 09:18:33PM +0300, Alexey Budankov wrote:
> >
> > Currently print count interval for performance counters values is
> > limited by 10ms so reading the values at frequencies higher than 100Hz
> > is restricted by the tool.
> >
> > This change makes perf stat -I possible on frequencies up to 1KHz and,
> > to some extent, makes perf stat -I to be on-par with perf record
> > sampling profiling.
> >
> > When running perf stat -I for monitoring e.g. PCIe uncore counters and
> > at the same time profiling some I/O workload by perf record e.g. for
> > cpu-cycles and context switches, it is then possible to observe
> > consolidated CPU/OS/IO(Uncore) performance picture for that workload.
> >
> > Tool overhead warning printed when specifying -v option can be missed
> > due to screen scrolling in case you have output to the console
> > so message is moved into help available by running perf stat -h.
> >
> > Signed-off-by: Alexey Budankov <alexey.budankov@xxxxxxxxxxxxxxx>
> > ---
> >
> > Changes in v2:
> > - updated minimum value to 1ms at perf-stat.txt manual
>
> Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>

Thanks, applied to perf/core.

- Arnaldo