Re: [PATCH RFC -tip 0/6] perf: IRQ-bound performance events

From: Jiri Olsa
Date: Tue Jun 04 2013 - 04:52:46 EST


On Mon, Jun 03, 2013 at 09:41:21PM +0200, Frederic Weisbecker wrote:
> On Mon, Jun 03, 2013 at 02:22:23PM +0200, Ingo Molnar wrote:
> >
> > * Alexander Gordeev <agordeev@xxxxxxxxxx> wrote:

SNIP

> How about we define finegrained context on top of perf events themselves?
> Like we could tell perf to count a task's instructions only after
> tracepoint:irq_entry is hit and stop counting when tracepoint:irq_exit.
>
> This way we can define any kind of fine grained context, not just irqs. We
> are not short on tracepoints, software events, breakpoints, kprobes, uprobes
> to play Legos there.

agreed, we could do the same as Alex did plus we'd have
the generic interface to meassure any place

>
> I had a branch with a working draft of that:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
> perf/custom-ctx-v2-pre
>
> Frederic Weisbecker (5):
> perf: Starter and stopper events
> perf: New enable_on_starter attribute
> perf: Support for starter and stopper in tools
> perf: New --enable-on-starter option
> perf: Add TODOs for event defined context
>
> It needs quite some improvements, (some are listed in the TODO on the last commit)
> especially in both the kernel and user interfaces.
>
> Jiri had some nice ideas about it.

yep, one of them is to to get back to this soon ;-)

jirka
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