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From: Namhyung Kim <namhyung@kernel.org>
To: Ian Rogers <irogers@google.com>
Cc: "Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Arnaldo Carvalho de Melo" <acme@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>,
	"Kan Liang" <kan.liang@linux.intel.com>,
	"Sam James" <sam@gentoo.org>,
	"Jesper Juhl" <jesperjuhl76@gmail.com>,
	"James Clark" <james.clark@linaro.org>,
	"Zhongqiu Han" <quic_zhonhan@quicinc.com>,
	"Yicong Yang" <yangyicong@hisilicon.com>,
	"Thomas Richter" <tmricht@linux.ibm.com>,
	"Michael Petlan" <mpetlan@redhat.com>,
	"Anne Macedo" <retpolanne@posteo.net>,
	"Dominique Martinet" <asmadeus@codewreck.org>,
	"Jean-Philippe Romain" <jean-philippe.romain@foss.st.com>,
	"Junhao He" <hejunhao3@huawei.com>,
	linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
	"Krzysztof Łopatowski" <krzysztof.m.lopatowski@gmail.com>
Subject: Re: [PATCH v3 0/8] Add io_dir to avoid memory overhead from opendir
Date: Mon, 24 Feb 2025 16:30:22 -0800	[thread overview]
Message-ID: <Z70PHtvzjHDLx42A@google.com> (raw)
In-Reply-To: <Z70OqFzD2JcbhFtL@google.com>

On Mon, Feb 24, 2025 at 04:28:24PM -0800, Namhyung Kim wrote:
> Hi Ian,
> 
> On Fri, Feb 21, 2025 at 10:10:05PM -0800, Ian Rogers wrote:
> > glibc's opendir allocates a minimum of 32kb, when called recursively
> > for a directory tree the memory consumption can add up - nearly 300kb
> > during perf start-up when processing modules. Add a stack allocated
> > variant of readdir sized a little more than 1kb
> 
> It's still small and hard to verify.  I've run the following command
> before and after the change but didn't see a difference.
> 
>   $ sudo time -f %Mk ./perf record -a true
>   [ perf record: Woken up 1 times to write data ]
>   [ perf record: Captured and wrote 1.757 MB perf.data (563 samples) ]
>   74724k
> 
> According to man time(1), %M is for max RSS.

But anyway, it looks ok and build is fine now.

Thanks,
Namhyung


  reply	other threads:[~2025-02-25  0:30 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-02-22  6:10 Ian Rogers
2025-02-22  6:10 ` [PATCH v3 1/8] tools lib api: Add io_dir an allocation free readdir alternative Ian Rogers
2025-02-22  6:10 ` [PATCH v3 2/8] perf maps: Switch modules tree walk to io_dir__readdir Ian Rogers
2025-02-22  6:10 ` [PATCH v3 3/8] perf pmu: Switch " Ian Rogers
2025-02-22  6:10 ` [PATCH v3 4/8] perf header: Switch mem topology " Ian Rogers
2025-02-22  6:10 ` [PATCH v3 5/8] perf events: Remove scandir in thread synthesis Ian Rogers
2025-02-22  6:10 ` [PATCH v3 6/8] perf parse-events: Switch tracepoints to io_dir__readdir Ian Rogers
2025-02-22  6:10 ` [PATCH v3 7/8] perf hwmon_pmu: Switch event discovery " Ian Rogers
2025-02-22  6:10 ` [PATCH v3 8/8] perf machine: Reuse module path buffer Ian Rogers
2025-02-25  0:28 ` [PATCH v3 0/8] Add io_dir to avoid memory overhead from opendir Namhyung Kim
2025-02-25  0:30   ` Namhyung Kim [this message]
2025-02-25  1:25     ` Ian Rogers
2025-02-25 21:58 ` Namhyung Kim

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