linux-kernel - Re: [PATCH 2/2 -tip] perf_counter: parse-events.c introduce alias member in event

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Message-ID: <20090622141009.GB6486@elte.hu>
Date:	Mon, 22 Jun 2009 16:10:09 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Jaswinder Singh Rajput <jaswinder@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2 -tip] perf_counter: parse-events.c introduce alias
	member in event_symbol


* Jaswinder Singh Rajput <jaswinder@...nel.org> wrote:

> On Mon, 2009-06-22 at 13:32 +0200, Ingo Molnar wrote:
> 
> > Another nice thing would be for 'perf list' to actually start each 
> > counter and stop it - and see whether it ticks. Perhaps that could 
> > be a new sub-command: 'perf test' ?
> > 
> > New 'perf' subcommands are added easily:
> > 
> > create a new tools/perf/builtin-foo.c file, add it to 
> > command-list.txt and to the Makefile - add it to perf.c's array of 
> > built-in commands and add a Documentation/perf-foo.txt file to 
> > generate manpages and usage strings for it.
> > 
> 
> Ok this is just a ugly quick hack to get the idea what actually you are
> looking for :
> 
> [RFC] perf_counter tools: introduce perf test to test each event for ticks
> 
> perf test to Test all events for whether it ticks
> 
>   $ perf test
> 
>   Performance counter stats for 'test':
> 
>   task-clock-msecs      Tick
>   context-switches      Tick
>   CPU-migrations        Tick
>   page-faults           Tick
>   cycles                Tick
>   instructions          Tick
>   cache-references      Tick
>   cache-misses          Tick
> 
>      0.007693869  seconds time elapsed.

yeah, somethig like that. I'd suggest to print out the actual 
measured events:

    cache-references      10123 events
    cache-misses             15 events

and if something does not appear to be ticking then do something 
like:

    cache-misses          <inactive>

I.e. 'perf test' could be a quick way both to users and to 
developers to see all possible hw and sw events.

Perhaps builtin-test.c should also do specific testcases for certain 
counters - say intentionally migrate to a CPU and back to see the 
CPU-migration count.

Also, you seem to have copied builtin-stat.c, right? Try to 
librarize as much of the functionality (into util/*) to make the 
resulting linecount increase as small as possible.

	Ingo
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