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From: Steven Rostedt <rostedt@goodmis.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC][PATCH 6/7] sched: Balance RT tasks when forked as well
Date: Tue, 26 Jul 2011 08:50:07 -0400	[thread overview]
Message-ID: <1311684607.3526.67.camel@gandalf.stny.rr.com> (raw)
In-Reply-To: <1311683818.24752.34.camel@twins>

On Tue, 2011-07-26 at 14:36 +0200, Peter Zijlstra wrote:
> On Tue, 2011-07-26 at 08:35 -0400, Steven Rostedt wrote:
> > On Tue, 2011-07-26 at 14:25 +0200, Peter Zijlstra wrote:
> > > On Thu, 2011-06-16 at 21:55 -0400, Steven Rostedt wrote:
> > > > +       /* For anything but wake ups, just return the task_cpu */
> > > > +       if (sd_flag != SD_BALANCE_WAKE || sd_flag != SD_BALANCE_FORK) 
> > > 
> > > So we call select_task_rq() with SD_BALANCE_{WAKE,EXEC,FORK}, 
> > > 
> > > 	(WAKE != WAKE -> 0 || WAKE != FORK -> 1) -> 1
> > > 	(EXEC != WAKE -> 1 ) -> 1
> > > 	(FORK != WAKE -> 1 ) -> 1
> > > 
> > > IOW, you never end up doing anything now.. surely you didn't mean that?!
> > 
> > Bah!
> > 
> > s/||/&&/
> 
> So you only want to rebalance on EXEC? The comment says you want to
> balance on wakeups. Please as to unconfuse!?

The patch is (with fixup):

+       /* For anything but wake ups, just return the task_cpu */
+       if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
+               goto out;

In other words, if it isn't a WAKE or FORK (FORK being new task wakeup)
then exit the routine.

EXEC should not rebalance.

-- Steve



  reply	other threads:[~2011-07-26 12:50 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-17  1:55 [RFC][PATCH 0/7] sched: various updates to the scheduler Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 1/7] sched: Fix need_resched() when checking peempt Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 2/7] sched: Remove noop in next_prio() Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 3/7] sched: Remove noop in lowest_flag_domain() Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 4/7] sched, rt: Fix rq->rt.pushable_tasks bug in push_rt_task() Steven Rostedt
2011-06-17  2:33   ` Mike Galbraith
2011-06-17  2:41     ` Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 5/7] sched: Remove resetting exec_start in put_prev_task_rt() Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 6/7] sched: Balance RT tasks when forked as well Steven Rostedt
2011-07-26 12:25   ` Peter Zijlstra
2011-07-26 12:35     ` Steven Rostedt
2011-07-26 12:36       ` Peter Zijlstra
2011-07-26 12:50         ` Steven Rostedt [this message]
2011-08-14 16:05   ` [tip:sched/core] " tip-bot for Steven Rostedt
2011-06-17  1:55 ` [RFC][PATCH 7/7] sched: Use pushable_tasks to determine next highest prio Steven Rostedt
2011-06-17  2:40 ` [RFC][PATCH 0/7] sched: various updates to the scheduler Steven Rostedt

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