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Date: Fri, 25 Sep 2026 12:42:45 +0200
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Sandipan Das <sandipan.das@amd.com>, Ian Rogers <irogers@google.com>
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	James Clark <james.clark@linaro.org>,
	Dapeng Mi <dapeng1.mi@linux.intel.com>,
	Borislav Petkov <bp@alien8.de>,
	Ravi Bangoria <ravi.bangoria@amd.com>,
	Ananth Narayan <ananth.narayan@amd.com>
Subject: Re: [PATCH] perf jevents: Limit the number of JSON reading workers
Message-ID: <arZQJZvMWyksoJ9E@x2>
References: <20260917095921.2802275-1-sandipan.das@amd.com>
 <CAP-5=fXcDT7Vi32odox1_gSbiGakN8KQMjXCZjmh=SyxuaVDZw@mail.gmail.com>
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On Fri, Sep 18, 2026 at 08:31:46AM -0700, Ian Rogers wrote:
> On Thu, Sep 17, 2026 at 3:00 AM Sandipan Das <sandipan.das@amd.com> wrote:
> > The ProcessPoolExecutor is created without max_workers, so
> > concurrent.futures defaults to one worker per CPU and forks all of them
> > when the first task is submitted. Each worker costs the parent a few
> > file descriptors. For systems with high core-count processors like the
> > AMD EPYC 9996, the pool can easily exhaust RLIMIT_NOFILE as seen below.
<SNIP>

> > Fixes: eaab2eb09dc2 ("perf pmu-events: Parallelize JSON and metric pre-computation in jevents.py")
 
> Reviewed-by: Ian Rogers <irogers@google.com>

Thanks, applied to perf-tools-next, for v7.4.

- Arnaldo