Re: Getting PMU stats on specific syscalls

[Kees Cook <keescook@chromium.org>]

On Tue, Jan 09, 2024 at 10:45:11PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Jan 09, 2024 at 05:04:54PM -0800, Kees Cook escreveu:
> > On January 9, 2024 3:30:32 PM PST, Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com> wrote:
> > >On Tue, Jan 9, 2024, 7:55 PM Kees Cook <keescook@chromium.org> wrote:
> > >> I'd like to get PMU stats only on specific syscalls. I haven't been able
> > >> to figure this out. i.e. how do I run:
> 
> > >>         perf stat -e some_syscall_name_here make -j128
> 
> > >> Try with the technique described here:
> 
> > >https://www.spinics.net/lists/linux-perf-users/msg09253.html
> 
> > >Using the syscalls:sys_enter_syscall_name and
> > >syscalls:sys_exit_syscall_name as on off switches.
>  
> > Yeah, I can get walk-clock time, but I'm trying to get much more
> > detailed stats (cache hits, cycle counts, etc).
>  
> > It seems I can only get PMU counts from a whole process. I was hoping
> > to avoid creating a synthetic workload that only exercises the one
> > syscall and instead get a view of the PMU counters under a real load
> > but only for the duration of the syscall...
> 
> This is the sequence I thought would do what you want:

Oh cool! Thanks for the example. I will give this a shot.

-- 
Kees Cook