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Subject: Re: [PATCH 5/6] lockstat: human readability tweaks
From: Matthew Helsley <matthltc@us.ibm.com>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-kernel@vger.kernel.org, Andrew Morton <akpm@linux-foundation.org>,
       Ingo Molnar <mingo@elte.hu>, Bill Huey <billh@gnuppy.monkey.org>,
       Jason Baron <jbaron@redhat.com>, Steven Rostedt <rostedt@goodmis.org>,
       Christoph Hellwig <hch@infradead.org>
In-Reply-To: <20070530125336.322824180@chello.nl>
References: <20070530124903.882133089@chello.nl>
	 <20070530125336.322824180@chello.nl>
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Date: Wed, 30 May 2007 12:39:05 -0700
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On Wed, 2007-05-30 at 14:49 +0200, Peter Zijlstra wrote:
> plain text document attachment (lockstat-output.patch)
> Present all this fancy new lock statistics information:
> 
> *warning, _wide_ output ahead*
> 
> (output edited for purpose of brevity)
> 
>  # cat /proc/lock_stat
> lock_stat version 0.1
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------
>                               class name    contentions   waittime-min   waittime-max waittime-total   acquisitions   holdtime-min   holdtime-max holdtime-total
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------

<snip>

> 'contentions' and 'acquisitions' are the number of such events measured (since 
> the last reset). The waittime- and holdtime- (min, max, total) numbers are 
> presented in microseconds.

I think it would make sense to actually mention the time scale in the
output header someplace. Then a tool written to analyze this file will
have a way of determining the time scale without using error-prone
heuristics (like "kernel version foo uses microseconds while kernel foo
+ 100 uses nanoseconds").

<snip>

Cheers,
	-Matt Helsley

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