linux-kernel - Re: Invalid event (cycles:pp) in per-thread mode, enable system wide with '-a'.

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Date:   Thu, 29 Sep 2022 20:23:45 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Slade Watkins <srw@...dewatkins.net>,
        Ravi Bangoria <ravi.bangoria@....com>
Cc:     Nick Desaulniers <ndesaulniers@...gle.com>,
        linux-perf-users@...r.kernel.org,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: Invalid event (cycles:pp) in per-thread mode, enable system wide
 with '-a'.

On Thu, Sep 29, 2022 at 3:10 PM Slade Watkins <srw@...dewatkins.net> wrote:
>
> Hey Nick,
>
> > On Sep 29, 2022, at 5:54 PM, Nick Desaulniers <ndesaulniers@...gle.com> wrote:
> >
> > I remember hearing rumblings about issues with zen 2, LBR, vs zen 3.
> > Is this a known issue, or am I holding it wrong?
>
> Hm… I also remember this. I have a Zen 2 based system that I can do testing on, so I will do so when I’m able.
>
> If I discover something of note, I’ll get back to you.
>
> Cheers,
> -srw
>

LBR isn't yet supported for Zen but is coming:
https://lore.kernel.org/lkml/166155216401.401.5809694678609694438.tip-bot2@tip-bot2/
I'd recommend frame-pointers.

+Ravi who may be able to say if there are any issues with the precise
sampling on AMD.

Thanks,
Ian