Re: [PATCH 3/3] scripts/performance: Add perf_top_25.py script

[Ahmed Karaman]

On Wed, Jun 17, 2020 at 2:21 PM Alex Bennée <alex.bennee@linaro.org> wrote:

> > +
> > +# Run perf repcord and report
> > +os.system('sudo perf record {} {} 2> /dev/null \
> > +            && sudo perf report --stdio > tmp.perf.data'
> > +          .format(qemu_path, executable))
>
> Why sudo?

This is the default requirement by perf. You can modify the
kernel.perf_event_paranoid setting to run without root privileges.

> Also redirecting just stderr? why?

Perf, as well as Valgrind, print their output on stderr not stdout.

> I think you could separate the steps (as well as use the subprocess
> api).

Noted!

> Again os.unlink()

Noted!