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Date: Mon, 24 Feb 2025 16:30:22 -0800
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 =?utf-8?Q?=C5=81opatowski?= <krzysztof.m.lopatowski@gmail.com>
Subject: Re: [PATCH v3 0/8] Add io_dir to avoid memory overhead from opendir
Message-ID: <Z70PHtvzjHDLx42A@google.com>
References: <20250222061015.303622-1-irogers@google.com>
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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