Re: [PATCH 0/4] perf lock contention: Improve call stack handling (v1)

[Arnaldo Carvalho de Melo]

Em Thu, Sep 08, 2022 at 04:44:15PM -0700, Namhyung Kim escreveu:
> Hi Arnaldo,
> 
> On Thu, Sep 8, 2022 at 11:43 AM Arnaldo Carvalho de Melo
> <acme@xxxxxxxxxx> wrote:
> >
> > Em Wed, Sep 07, 2022 at 11:37:50PM -0700, Namhyung Kim escreveu:
> > > Hello,
> > >
> > > I found that call stack from the lock tracepoint (using bpf_get_stackid)
> > > can be different on each configuration.  For example it's very different
> > > when I run it on a VM than on a real machine.
> > >
> > > The perf lock contention relies on the stack trace to get the lock
> > > caller names, this kind of difference can be annoying.  Ideally we could
> > > skip stack trace entries for internal BPF or lock functions and get the
> > > correct caller, but it's not the case as of today.  Currently it's hard
> > > coded to control the behavior of stack traces for the lock contention
> > > tracepoints.
> > >
> > > To handle those differences, add two new options to control the number of
> > > stack entries and how many it skips.  The default value worked well on
> > > my VM setup, but I had to use --stack-skip=5 on real machines.
> > >
> > > You can get it from 'perf/lock-stack-v1' branch in
> > >
> > >   git://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
> >
> > This clashed with a patch you Acked earlier, so lets see if someone has
> > extra review comments and a v2 become needed for other reason, when you
> > can refresh it, ok?
> 
> Sounds good!

Have you resubmitted this? /me goes on the backlog...

- Arnaldo