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From: David Ahern <dsahern@gmail.com>
To: Namhyung Kim <namhyung@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: "Adrian Hunter" <adrian.hunter@intel.com>,
	"Jiri Olsa" <jolsa@kernel.org>, "Ingo Molnar" <mingo@kernel.org>,
	"Frédéric Weisbecker" <fweisbec@gmail.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>
Subject: Re: heads up/RFC: 'perf trace' using ordered_events
Date: Tue, 10 Mar 2015 08:25:27 -0600	[thread overview]
Message-ID: <54FEFED7.5000503@gmail.com> (raw)
In-Reply-To: <20150310060644.GC943@sejong>

On 3/10/15 12:06 AM, Namhyung Kim wrote:
> Hi Arnaldo,
>
> On Mon, Mar 09, 2015 at 10:21:35AM -0300, Arnaldo Carvalho de Melo wrote:
>> For trace I need to take advantage of the fact that each mmap is ordered
>> already and then just sort by the timestamp in the mmap head, etc.
>>
>> In retrospect, the perf.data file should have kept that ordering, i.e.
>> have one file per mmap, that would be saved in parallel, without any of
>> those PERF_RECORD_FINISHED_ROUND records.
>>
>> But I have to experiment with that, leaving the existing code around to
>> deal with older files.
>
> It seems like what you said is almost same as my multi-thread work.
> It saves data files per mmap and then merges them with an index
> table so that they can be processed in parallel.

I think you and Jiri both have worked on saving a file per mmap. Where 
does that stand? I would like to try it out.

With the 1024 cpu systems I am seeing 5GB files in 1 second runs and 
perf is not handling it well. The perf-script/perf-report (stdio) will 
'hang' for 45 minutes munging through the file. I have to connect gdb 
from time to time to verify it is making progress (file_offset is 
increasing). I believe what happens is that there is 'no round' -- it 
has to process all mmaps (1024 cpus and 6 or 7 events) through the 
ordered events queue before it can push out results. I need to look at 
that once I figure out the task scheduler problem.

David


  reply	other threads:[~2015-03-10 14:25 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03 16:49 Arnaldo Carvalho de Melo
2015-03-04  1:01 ` Namhyung Kim
2015-03-04  1:07   ` Arnaldo Carvalho de Melo
2015-03-07 12:45     ` Adrian Hunter
2015-03-09 13:21       ` Arnaldo Carvalho de Melo
2015-03-10  6:06         ` Namhyung Kim
2015-03-10 14:25           ` David Ahern [this message]
2015-03-11  0:33             ` Namhyung Kim

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