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From: Con Kolivas <kernel@kolivas.org>
To: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: "'Nick Piggin'" <nickpiggin@yahoo.com.au>,
	linux-kernel@vger.kernel.org, "'Chris Mason'" <mason@suse.com>,
	"Ingo Molnar" <mingo@elte.hu>
Subject: Re: [PATCH RFC] smt nice introduces significant lock contention
Date: Fri, 2 Jun 2006 19:34:26 +1000	[thread overview]
Message-ID: <200606021934.27420.kernel@kolivas.org> (raw)
In-Reply-To: <000101c68627$4866eff0$0c4ce984@amr.corp.intel.com>

On Friday 02 June 2006 19:31, Chen, Kenneth W wrote:
> Con Kolivas wrote on Friday, June 02, 2006 2:25 AM
>
> > On Friday 02 June 2006 19:17, Chen, Kenneth W wrote:
> > > What about the part in dependent_sleeper() being so bully and actively
> > > resched other low priority sibling tasks?  I think it would be better
> > > to just let the tasks running on sibling CPU to finish its current time
> > > slice and then let the backoff logic to kick in.
> >
> > That would defeat the purpose of smt nice if the higher priority task
> > starts after the lower priority task is running on its sibling cpu.
>
> But only for the duration of lower priority tasks' time slice.  When lower
> priority tasks time slice is used up, a resched is force from
> scheduler_tick(), isn't it?  And at that time, it is delayed to run because
> of smt_nice.  You are saying user can't tolerate that short period of time
> that CPU resource is shared?  It's hard to believe.

nice -20 vs nice 0 is 800ms vs 100ms. That's a long time to me.

-- 
-ck

  reply	other threads:[~2006-06-02  9:34 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-06-01 22:55 Chris Mason
2006-06-01 23:57 ` Chen, Kenneth W
2006-06-02  1:59   ` Con Kolivas
2006-06-02  2:28     ` Con Kolivas
2006-06-02  3:55       ` Con Kolivas
2006-06-02  4:18         ` Nick Piggin
2006-06-02  6:08           ` Con Kolivas
2006-06-02  7:53             ` Nick Piggin
2006-06-02  8:17               ` Con Kolivas
2006-06-02  8:28                 ` Nick Piggin
2006-06-02  8:34                   ` Chen, Kenneth W
2006-06-02  8:56                     ` Nick Piggin
2006-06-02  9:17                       ` Chen, Kenneth W
2006-06-02  9:25                         ` Con Kolivas
2006-06-02  9:31                           ` Chen, Kenneth W
2006-06-02  9:34                             ` Con Kolivas [this message]
2006-06-02  9:53                               ` Chen, Kenneth W
2006-06-02 10:12                                 ` Con Kolivas
2006-06-02 20:53                                   ` Chen, Kenneth W
2006-06-02 22:15                                     ` Con Kolivas
2006-06-02 22:19                                       ` Chen, Kenneth W
2006-06-02 22:31                                         ` Con Kolivas
2006-06-02 22:58                                           ` Chen, Kenneth W
2006-06-03  0:02                                             ` Con Kolivas
2006-06-03  0:08                                               ` Chen, Kenneth W
2006-06-03  0:27                                                 ` Con Kolivas
2006-06-02  9:36                       ` Chen, Kenneth W
2006-06-02 10:30                       ` Con Kolivas
2006-06-02 13:16                         ` Con Kolivas
2006-06-02 21:54                           ` Chen, Kenneth W
2006-06-02 22:04                             ` Con Kolivas
2006-06-02 22:14                       ` Chen, Kenneth W
2006-06-02 10:19                   ` Con Kolivas
2006-06-02 20:59                     ` Chen, Kenneth W
2006-06-02  8:38               ` Chen, Kenneth W
2006-06-02  8:24           ` Chen, Kenneth W
2006-06-02  8:31         ` Chen, Kenneth W
2006-06-02  8:50         ` Chen, Kenneth W
2006-06-02  2:35     ` Chen, Kenneth W
2006-06-02  3:04       ` Con Kolivas
2006-06-02  3:23         ` Con Kolivas

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