From mboxrd@z Thu Jan  1 00:00:00 1970
From: jbaron@redhat.com (Jason Baron)
Date: Mon, 8 Dec 2008 17:38:40 -0500
Subject: [ltt-dev] [patch] add tracepoints to trace activate/deactivate
	task
In-Reply-To: <1228766050.6939.7.camel@twins>
References: <20081208194948.GC27166@redhat.com> <1228766050.6939.7.camel@twins>
Message-ID: <20081208223840.GA30314@redhat.com>

On Mon, Dec 08, 2008 at 08:54:10PM +0100, Peter Zijlstra wrote:
> On Mon, 2008-12-08 at 14:49 -0500, Jason Baron wrote:
> > hi,
> > 
> > I thought it would be useful to track when a task is
> > 'activated/deactivated'. This case is different from wakeup/wait, in that
> > task can be activated and deactivated, when the scheduler re-balances
> > tasks, the allowable cpuset changes, or cpu hotplug occurs. Using these
> > patches I can more precisely figure out when a task becomes runnable and
> > why. 
> 
> Then I still not agree with it because it does not expose the event that
> did the change.
> 
> If you want the cpu allowed mask, put a tracepoint there. If you want
> migrate information (didn't we have that?) then put one there, etc.
> 

well, with stap backtrace I can figure out the event, otherwise i'm
sprinkling 14 more trace events in the scheduler...I can go down that
patch if people think its better?

thanks,

-Jason