From mboxrd@z Thu Jan  1 00:00:00 1970
From: mingo@elte.hu (Ingo Molnar)
Date: Wed, 25 Mar 2009 09:47:24 +0100
Subject: [ltt-dev] [patch 2/9] LTTng instrumentation - irq
In-Reply-To: <20090324205120.GB24320@elte.hu>
References: <20090324155625.420966314@polymtl.ca>
	<20090324160148.080628193@polymtl.ca>
	<20090324173354.GC3129@redhat.com> <20090324175049.GC31117@elte.hu>
	<20090324175750.GE3129@redhat.com> <20090324191252.GA11665@elte.hu>
	<20090324201146.GA4350@Krystal> <20090324205120.GB24320@elte.hu>
Message-ID: <20090325084724.GA28171@elte.hu>


* Ingo Molnar <mingo at elte.hu> wrote:

> 
> * Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca> wrote:
> 
> > If we want to do this logically, without thinking about tracer 
> > performance impact, we could/should do :
> > 
> > trace_irq_entry(irqno, pt_regs)
> >   for_each_handler() {
> >     trace_irq_handler_entry(action)
> >     action->handler()
> >     trace_irq_handler_exit(ret)
> >   }
> > trace_irq_exit(retval)
> 
> Not really.

Put differently: we seem to agree on handler invocation entry/exit 
events (and those are handled by Jason's patch already), and that's 
good.

I dont think we need two events for physical IRQ events though. One 
is enough: entry event. What meaning does 'retval' have in your 
pseudo-code above? None typically.

	Ingo