Re: [PATCH 15/15] perf mem record: Use the IBS swfilt filter when available

[sashiko-bot@kernel.org]

> From: Arnaldo Carvalho de Melo <acme@redhat.com>
> 
> IBS events with exclude_{user,kernel} bits, as used for per-thread
> recording when kernel samples are not allowed, are rejected by the
> kernel on hardware without the privilege filter, so per-thread 'perf mem
> record' fails on AMD:
> 
>   $ perf mem record -o /dev/null -- true
>   Error:
>   Failure to open event 'ibs_op/ldlat=0/u' on PMU 'ibs_op' which will be removed.
>   Invalid event (ibs_op/ldlat=0/u) in per-thread mode, enable system wide with '-a'.
> 
> Kernel v6.14 added swfilt, a software privilege filter exposed as the
> 'swfilt' format term, making those events usable per-thread:
> 
>   $ perf record -e ibs_op/ldlat=0,swfilt=1/ -- true
> 
> Give the ibs_op memory events a name variant with the swfilt term, used
> when the PMU exposes it, even when the record ends up without exclude
> bits: 'perf record' adds those bits itself when the first open fails,
> after the name was built, and that retry needs the term.  This makes the
> per-thread 'perf mem record' the data type profiling shell test does
> work on AMD kernels with swfilt, and the test's event regex is adjusted
> for the added term.
> 
> Suggested-by: Namhyung Kim <namhyung@kernel.org>
> Assisted-by: LLM
> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260917155528.62607-1-acme@kernel.org?part=15