linux-kernel - Re: [PATCH V2] perf: Speed up thread map generation

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Date:	Fri, 14 Mar 2014 17:12:06 +0100
From:	Jiri Olsa <jolsa@...hat.com>
To:	Don Zickus <dzickus@...hat.com>
Cc:	acme@...hat.com, jmario@...hat.com,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH V2] perf: Speed up thread map generation

On Fri, Mar 14, 2014 at 10:43:44AM -0400, Don Zickus wrote:
> When trying to capture perf data on a system running spejbb2013,
> perf hung for about 15 minutes.  This is because it took that
> long to gather about 10,000 thread maps and process them.
> 
> I don't think a user wants to wait that long.
> 
> Instead, recognize that thread maps are roughly equivalent to
> pid maps and just quickly copy those instead.
> 
> To do this, I synthesize 'fork' events, this eventually calls
> thread__fork() and copies the maps over.
> 
> The overhead goes from 15 minutes down to about a few seconds.
> 
> Signed-off-by: Don Zickus <dzickus@...hat.com>
> --
> V2: based on Jiri's comments, moved malloc up a level
>     and made sure the memory was freed

Acked-by: Jiri Olsa <jolsa@...hat.com>

thanks,
jirka
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