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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Wed, 21 Jun 2023 15:50:39 -0700
Message-ID: <CAM9d7chNA44HxRYOHLxtBP_7azivrE_MxdKos1gUO3KxnbK_Dw@mail.gmail.com>
Subject: Re: [PATCH] perf/amd: Prevent grouping of IBS events
To:     Ravi Bangoria <ravi.bangoria@amd.com>
Cc:     Ian Rogers <irogers@google.com>, peterz@infradead.org,
        acme@kernel.org, jolsa@kernel.org, bp@alien8.de, x86@kernel.org,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        sandipan.das@amd.com, ananth.narayan@amd.com,
        santosh.shukla@amd.com
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On Tue, Jun 20, 2023 at 8:28 PM Ravi Bangoria <ravi.bangoria@amd.com> wrote:
>
> Hi Ian,
>
> On 20-Jun-23 10:14 PM, Ian Rogers wrote:
> > On Tue, Jun 20, 2023 at 2:16 AM Ravi Bangoria <ravi.bangoria@amd.com> wrote:
> >>
> >> IBS PMUs can have only one event active at any point in time. Restrict
> >> grouping of multiple IBS events.
> >
> > Thanks Ravi,
> >
> > can you provide an example/test for this? Should this be a weak group issue?
>
> Before:
>   $ sudo ./perf record -e "{ibs_op//,ibs_op//}" -C 0
>   ^C[ perf record: Woken up 1 times to write data ]
>   [ perf record: Captured and wrote 0.540 MB perf.data (531 samples) ]
>
> After:
>   $ sudo ./perf record -e "{ibs_op//,ibs_op//}" -C 0
>   Error:
>   AMD IBS may only be available in system-wide/per-cpu mode.
>   Try using -a, or -C and workload affinity
>
> The error message is stale and misleading. I have a patch to fix it.
> I'll post it separately.

I'm just curious if ibs_fetch and ibs_op can be grouped together.

Thanks,
Namhyung