Date: Sat, 12 Sep 2009 16:03:20 +0200
From: Ingo Molnar <mingo@elte.hu>
To: Arjan van de Ven <arjan@infradead.org>
Cc: linux-kernel@vger.kernel.org, fweisbec@gmail.com, peterz@infradead.org,
       Paul Mackerras <paulus@samba.org>
Subject: Re: [patch 0/8] Introducing the "timechart" tool
Message-ID: <20090912140320.GA9292@elte.hu>
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* Arjan van de Ven <arjan@infradead.org> wrote:

> [note: since this is a visualization tool, and lkml doesn't like 
> html email, it's probably better to read the online version at
> 
> http://blog.fenrus.org/?p=5
> 
> in which I also show screenshots of the tool. The following text 
> is the first part of the online introduction]
> 
> Finding out why your Linux computer performs the way it does has 
> been a hard task. Sure, there is Oprofile, and even ???perf??? in 
> recent kernels. There is LatencyTOP to find out where latencies 
> happen.
> 
> But all of these tools are rather limited when the software stack 
> that has the performance issue is more complex than a single 
> program. The tool that comes closest to being useful is 
> `bootchart???, but that has a rather limited resolution.
> 
> To solve this, I have been working on a new tool, called 
> Timechart, that has the objective to show on a system level what 
> is going on, at various levels of detail. In fact. one of the 
> design ideas behind timechart is that the output should be 
> ???infinitely zoomable???; that is, if you want to know more 
> details about something, you should be able to zoom in to get 
> these details. The rest of this blog post describes some aspects 
> of timechart, using real life examples and screenshots. However, 
> it is really hard to show the power of timechart on such a static 
> page, to get a real feeling of what timechart can show you really 
> ought to try it out yourself.....

Nice! 'perf timechart' is IMO a really intuitive way to visualize 
perf record output.

Text output goes only so far - patterns of scheduling (and patterns 
of bad behavior) are a lot easier to notice in SVGs.

	Ingo
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