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Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing

From David Ahern <dsahern@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap processing
Date 2015-06-13 06:30 +0200
Message-ID <pALeW-1St-1@gated-at.bofh.it> (permalink)
References (7 earlier) <pAACS-3sz-15@gated-at.bofh.it> <pAAWd-3PM-5@gated-at.bofh.it> <pABIB-50T-5@gated-at.bofh.it> <pACOm-6z8-1@gated-at.bofh.it> <pAE3L-8j4-11@gated-at.bofh.it>
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coming back to this ...

On 6/12/15 2:39 PM, Liang, Kan wrote:
>>> Yes, perf always can read proc file. The problem is that the proc file
>>> is huge and keep growing faster than proc reader.
>>> So perf top do loop in perf_event__synthesize_mmap_events until the
>>> test case exit.
>>
>> I'm confused. How are you getting the above time to read /proc maps if it
>> never finishes?
>
> I just tried to simplify the issue for perf record. So you may noticed that
> I only read one thread. There are several threads in the system.
> Also, I do the perf record test when starting the test case.
> The proc file is not that big.
> For perf top, it will monitor whole system. So it never finishes.

If the proc file is not that big for perf-record why is it a problem for 
perf-top? Both should only be reading the maps file for the thread group 
leader once and after it is processed getting MMAP events for changes. 
Why do you say perf-top can't handle it but perf-record can?

David
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Thread

Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap  processing David Ahern <dsahern@gmail.com> - 2015-06-12 02:40 +0200
  Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap  processing David Ahern <dsahern@gmail.com> - 2015-06-13 06:10 +0200
  Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap  processing David Ahern <dsahern@gmail.com> - 2015-06-13 06:30 +0200
    Re: [PATCH 1/1] perf,tools: add time out to force stop endless mmap  processing Arnaldo Carvalho de Melo <acme@kernel.org> - 2015-06-16 20:10 +0200

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