Re: [PATCH] perf record: Fix perf_can_aux_sample_size()

[Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>]

Em Fri, Nov 22, 2019 at 10:42:57AM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Fri, Nov 22, 2019 at 11:48:56AM +0200, Adrian Hunter escreveu:
> > perf_can_aux_sample_size() always returned true because it did not pass
> > the attribute size to sys_perf_event_open, nor correctly check the
> > return value and errno.
> > 
> > Before:
> > 
> >   # perf record --aux-sample -e '{intel_pt//u,branch-misses:u}'
> >   Error:
> >   The sys_perf_event_open() syscall returned with 7 (Argument list too long) for event (branch-misses:u).
> >   /bin/dmesg | grep -i perf may provide additional information.
> > 
> > After:
> > 
> >   # perf record --aux-sample -e '{intel_pt//u,branch-misses:u}'
> >   AUX area sampling is not supported by kernel
> 
> Since this hasn't been sent to Ingo, I combined it with the patch that
> introduced the problem, this one:
> 
> c31d79e7a052 perf record: Add a function to test for kernel support for AUX area sampling
> 
> Thanks for the quick fix,

Wrapping up, at the end of the series I now get:

  [root@quaco ~]# perf record --aux-sample -e '{intel_pt//u,branch-misses:u}'
  AUX area sampling is not supported by kernel
  [root@quaco ~]#
  [root@quaco ~]# uname -a
  Linux quaco 5.4.0-rc8 #1 SMP Mon Nov 18 06:15:31 -03 2019 x86_64 x86_64 x86_64 GNU/Linux
  [root@quaco ~]#

Thanks,

- Arnaldo