linux-kernel - Re: [PATCH 4/6 -tip] perf_counter: Add Generalized Hardware interrupt support for AMD

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Message-ID: <20090701112406.GE15958@elte.hu>
Date:	Wed, 1 Jul 2009 13:24:06 +0200
From:	Ingo Molnar <mingo@...e.hu>
To:	Jaswinder Singh Rajput <jaswinder@...nel.org>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arjan van de Ven <arjan@...radead.org>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Paul Mackerras <paulus@...ba.org>,
	Anton Blanchard <anton@...ba.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>,
	Peter Zijlstra <peterz@...radead.org>,
	x86 maintainers <x86@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Alan Cox <alan@...rguk.ukuu.org.uk>
Subject: Re: [PATCH 4/6 -tip] perf_counter: Add Generalized Hardware
	interrupt support for AMD


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

> 
> $ ./perf stat -e interrupts -e masked -e int-pending-mask-cycles -- ls -lR /usr/include/ > /dev/null
> 
>  Performance counter stats for 'ls -lR /usr/include/':
> 
>             377  interrupts
>        53429936  int-mask-cycles
>            1119  int-pending-mask-cycles
> 
>     0.371457539  seconds time elapsed

Agreed, this is another useful generalization - and the 'cycles 
pending' metrics are not retrievable via any software means.

We could and should probably add a software counter for hardirqs as 
wel. That would allow the vector/irqnr information to be passed in, 
and it would allow architectures without irq metrics in the PMU to 
have this counter too.

This way we could profile based on a specific interrupt source only 
- say based on the networking card.

	Ingo
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