From: Andi Kleen <ak@linux.intel.com>
To: Ian Rogers <irogers@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>,
Adrian Hunter <adrian.hunter@intel.com>,
"Dr. David Alan Gilbert" <linux@treblig.org>,
Yang Li <yang.lee@linux.alibaba.com>,
James Clark <james.clark@linaro.org>,
Thomas Falcon <thomas.falcon@intel.com>,
Thomas Richter <tmricht@linux.ibm.com>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
Dapeng Mi <dapeng1.mi@linux.intel.com>
Subject: Re: [PATCH v5 3/3] perf stat: Add no-affinity flag
Date: Wed, 19 Nov 2025 07:37:27 -0800 [thread overview]
Message-ID: <aR3kN1GiKki4AO9b@tassilo> (raw)
In-Reply-To: <CAP-5=fWSXboT2jEYtua_N8AnaXc0SUeoC2iBgxSz5QRF09bfoQ@mail.gmail.com>
> Ack. This is only adding the flag to perf stat, are the storms as much
> of an issue there? Patch 2 of 3 changes it so that for a single event
> we still use affinities, where a dummy and an event count as >1 event.
Not sure I follow here. I thought you disabled it completely?
> We have specific examples of loaded machines where the scheduling
> latency causes broken metrics - the flag at least allows investigation
> of issues like this. I don't mind reviewing a patch adding real time
> priorities as an option.
You don't need a new flag. Just run perf with real time priority with
any standard wrapper tool, like chrt. The main obstacle is that you may
need the capability to do that though.
-Andi
next prev parent reply other threads:[~2025-11-19 15:37 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-18 21:13 [PATCH v5 0/3] perf stat affinity changes Ian Rogers
2025-11-18 21:13 ` [PATCH v5 1/3] perf stat: Read tool events last Ian Rogers
2025-11-19 18:12 ` Namhyung Kim
2025-11-18 21:13 ` [PATCH v5 2/3] perf evlist: Reduce affinity use and move into iterator, fix no affinity Ian Rogers
2025-11-18 21:13 ` [PATCH v5 3/3] perf stat: Add no-affinity flag Ian Rogers
2025-11-18 23:19 ` Andi Kleen
2025-11-19 0:58 ` Ian Rogers
2025-11-19 15:37 ` Andi Kleen [this message]
2025-11-19 16:25 ` Ian Rogers
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