Ahmed Karaman <ahmedkhaledkara...@gmail.com> writes:
> On Wed, Jun 17, 2020 at 2:21 PM Alex Bennée <alex.ben...@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.
Right - which I do as a developer. It would be rude to sudo things if
you don't need to because then you end up running your potentially
un-trusted application with root privileges.
Could we either probe for the requirement or require an explicit sudo
flag which we can prompt for if it fails?
>
>> Also redirecting just stderr? why?
>
> Perf, as well as Valgrind, print their output on stderr not stdout.
Right so I think a bit of splitting apart and use of subprocess can make
this cleaner and not involve quite so much being done with shell
redirection in one invocation.
>
>> I think you could separate the steps (as well as use the subprocess
>> api).
>
> Noted!
>
>> Again os.unlink()
>
> Noted!
--
Alex Bennée
