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Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1)

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On December 10, 2015 5:01:18 PM GMT+09:00, Ingo Molnar <mingo@kernel.org> wrote:
>
>* Namhyung Kim <namhyung@kernel.org> wrote:
>
>> Hello,
>> 
>> This patchset if an attempt to support multi-threading in perf top.
>> In fact, perf top already run on two threads - a worker thread and a
>> display thread.  However processing all samples with a single thread
>> in a large machine can have scalability problems.
>> 
>> This patchset extends it to have multiple worker threads to process
>> samples concurrently.  Users can control the number of threads using
>>  --num-thread option.  And there's a collector thread for passing
>hist
>> entries from worker threads to the display thread.
>
>Could you please make the number of threads default to the number of
>CPUs?
>
>Since perf top is doing one perf event per CPU anyway, that's a pretty
>natural 
>model.
>
>( I think 'perf record' should use per CPU threads as well to receive
>events, to 
>address the 'IO overload' problems with -g recording on larger CPU
>counts. )

IIRC David said that thread per cpu seems too much
especially on a large system (like ~1024 cpu).  I have no idea 
what's the reasonable default on the system, so I chose 1/4 
of map buffers (i.e. cpus for most cases). But I think I should
take non-system-wide mode into account too.

Thanks
Namhyung

Hi Ingo,
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[PATCHSET 00/16] perf top: Add multi-thread support (v1) Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 03/16] perf top: Factor out warnings about kernel addresses and symbols Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
    Re: [PATCH/RFC 03/16] perf top: Factor out warnings about kernel  addresses and symbols Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-12-10 20:10 +0100
  [PATCH/RFC 14/16] perf top: Separate struct perf_top_stats Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 11/16] perf top: Implement basic parallel processing Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 01/16] perf top: Delete half-processed hist entries when exit Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
    RE: [PATCH/RFC 01/16] perf top: Delete half-processed hist entries  when exit 平松雅巳 / HIRAMATU，MASAMI   <masami.hiramatsu.pt@hitachi.com> - 2015-12-10 11:00 +0100
      Re: [PATCH/RFC 01/16] perf top: Delete half-processed hist entries  when exit Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-12-10 20:00 +0100
  [PATCH/RFC 10/16] perf hist: Add events_stats__add() and hists__add_stats() Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 16/16] perf tools: Skip dso front cache for multi-threaded lookup Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 04/16] perf top: Factor out warnings in perf_top__record_precise_ip() Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 15/16] perf top: Add --num-thread option Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  [PATCH/RFC 09/16] perf tools: Update hist entry's hists pointer Namhyung Kim <namhyung@kernel.org> - 2015-12-10 09:00 +0100
  Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1) Ingo Molnar <mingo@kernel.org> - 2015-12-10 09:10 +0100
    Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1) Namhyung Kim <namhyung@gmail.com> - 2015-12-10 09:50 +0100
      Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1) Ingo Molnar <mingo@kernel.org> - 2015-12-11 09:20 +0100
        Re: [PATCHSET 00/16] perf top: Add multi-thread support (v1) David Ahern <dsahern@gmail.com> - 2015-12-11 16:10 +0100

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