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Date:   Wed, 23 Oct 2019 09:55:17 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Jiri Olsa <jolsa@kernel.org>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        lkml <linux-kernel@vger.kernel.org>,
        Ingo Molnar <mingo@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Michael Petlan <mpetlan@redhat.com>,
        Andi Kleen <ak@linux.intel.com>,
        Stephane Eranian <eranian@google.com>,
        Jin Yao <yao.jin@linux.intel.com>,
        Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: Re: [PATCHv2 0/2] perf tools: Share struct map after clone
Message-ID: <20191023075517.GA22919@krava>
References: <20191016082226.10325-1-jolsa@kernel.org>
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On Wed, Oct 16, 2019 at 10:22:24AM +0200, Jiri Olsa wrote:
> hi,
> Andi reported that maps cloning is eating lot of memory and
> it's probably unnecessary, because they keep the same data.
>=20
> This 'maps sharing' seems to save lot of heap for reports with
> many forks/cloned mmaps (over 60% in example below).
>=20
> Profile kernel build:
>=20
>   $ perf record make -j 40
>=20
> Get heap profile (tools/perf directory):
>=20
>   $ <install gperftools>
>   $ make TCMALLOC=3D1
>   $ HEAPPROFILE=3D/tmp/heapprof ./perf report -i perf.data --stdio > out
>   $ pprof ./perf /tmp/heapprof.000*
>=20
> Before:
>=20
>   (pprof) top
>   Total: 2335.5 MB
>     1735.1  74.3%  74.3%   1735.1  74.3% memdup
>      402.0  17.2%  91.5%    402.0  17.2% zalloc
>      140.2   6.0%  97.5%    145.8   6.2% map__new
>       33.6   1.4%  98.9%     33.6   1.4% symbol__new
>       12.4   0.5%  99.5%     12.4   0.5% alloc_event
>        6.2   0.3%  99.7%      6.2   0.3% nsinfo__new
>        5.5   0.2% 100.0%      5.5   0.2% nsinfo__copy
>        0.3   0.0% 100.0%      0.3   0.0% dso__new
>        0.1   0.0% 100.0%      0.1   0.0% do_read_string
>        0.0   0.0% 100.0%      0.0   0.0% __GI__IO_file_doallocate
>=20
> After:
>=20
>   (pprof) top
>   Total: 784.5 MB
>      385.8  49.2%  49.2%    385.8  49.2% memdup
>      285.8  36.4%  85.6%    285.8  36.4% zalloc
>       80.4  10.3%  95.9%     83.7  10.7% map__new
>       19.1   2.4%  98.3%     19.1   2.4% symbol__new
>        6.2   0.8%  99.1%      6.2   0.8% alloc_event
>        3.6   0.5%  99.6%      3.6   0.5% nsinfo__new
>        3.2   0.4% 100.0%      3.2   0.4% nsinfo__copy
>        0.2   0.0% 100.0%      0.2   0.0% dso__new
>        0.0   0.0% 100.0%      0.0   0.0% do_read_string
>        0.0   0.0% 100.0%      0.0   0.0% elf_fill
>=20
> v2 changes:
>   - rebased to Arnaldo's perf/core
>   - patch 1 already taken
>=20
> Also available in here:
>   git://git.kernel.org/pub/scm/linux/kernel/git/jolsa/perf.git
>   perf/map_shared

I rebased to latest perf/core and pushed the branch out

jirka