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 v3 9/9] perf stat: Add no-affinity flag
Date: Thu, 06 Nov 2025 09:31:33 -0800 [thread overview]
Message-ID: <87cy5v3w5m.fsf@linux.intel.com> (raw)
In-Reply-To: <20251106071241.141234-10-irogers@google.com> (Ian Rogers's message of "Wed, 5 Nov 2025 23:12:40 -0800")
Ian Rogers <irogers@google.com> writes:
> Add flag that disables affinity behavior. Using sched_setaffinity to
> place a perf thread on a CPU can avoid certain interprocessor
> interrupts but may introduce a delay due to the scheduling,
> particularly on loaded machines. Add a command line option to disable
> the behavior. This behavior is less present in other tools like `perf
> record`, as it uses a ring buffer and doesn't make repeated system
> calls.
I would rather use a real time scheduling policy instead if you see starvation.
That would still get the batching efficiency.
If it's done it would be better in .perfconfig instead of adding ever
more obscure command line options.
-Andi
prev parent reply other threads:[~2025-11-06 17:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-06 7:12 [PATCH v3 0/9] perf stat fixes and improvements Ian Rogers
2025-11-06 7:12 ` [PATCH v3 1/9] libperf cpumap: Reduce allocations and sorting in intersect Ian Rogers
2025-11-06 7:12 ` [PATCH v3 2/9] perf pmu: perf_cpu_map__new_int to avoid parsing a string Ian Rogers
2025-11-06 7:12 ` [PATCH v3 3/9] perf tool_pmu: Use old_count when computing count values for time events Ian Rogers
2025-11-06 7:12 ` [PATCH v3 4/9] perf stat-shadow: Read tool events directly Ian Rogers
2025-11-06 7:12 ` [PATCH v3 5/9] perf stat: Reduce scope of ru_stats Ian Rogers
2025-11-06 7:12 ` [PATCH v3 6/9] perf tool_pmu: More accurately set the cpus for tool events Ian Rogers
2025-11-06 7:12 ` [PATCH v3 7/9] perf evlist: Reduce affinity use and move into iterator, fix no affinity Ian Rogers
2025-11-06 7:12 ` [PATCH v3 8/9] perf stat: Read tool events last Ian Rogers
2025-11-06 7:12 ` [PATCH v3 9/9] perf stat: Add no-affinity flag Ian Rogers
2025-11-06 17:31 ` Andi Kleen [this message]
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