Re: [PATCH 5/6] tracing, documentation: Add a document describinghow to do some performance analysis with tracepoints

From: Mel Gorman
Date: Fri Aug 07 2009 - 10:25:43 EST


On Fri, Aug 07, 2009 at 10:07:07AM +0200, Ingo Molnar wrote:
> > <SNIP>
>
> This is a very nice and comprehensive description!
>

Thanks, you did write a nice chunk of it yourself though :)

> I'm wondering: would you mind if we integrated the analysis ideas
> from your perl script into 'perf trace'? Those kinds of high-level
> counts and summaries are useful not just for MM events.
>

Of course not. Part of the motivation for doing the perl script was as a
POC for the gathering of high-level events. In the event such sample
scripts work out, it'd justify the greater effort to integrate them into
perf.

> Another thing that was raise dbefore is a 'perf mem' special-purpose
> tool to help the analysis of all things memory related: leak
> detection, high level stats, etc. That could have some turn-key
> modes of analysis for the page allocator too.
>

Again, my vague notion was to prototype such things in perl and then when it
works out to incorporate it in perf if suitable. As high-level gathering of
information is just a state machine, it's conceivable that some of the code
could be auto-generated.

> perf will do a proper format-string evaluation of
> /debug/tracing/events/*/format as well, thus any tweaks to the
> tracepoints get automatically adopted to.
>

Which would be a major plus.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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