From: Mike Galbraith <efault@gmx.de>
To: Con Kolivas <kernel@kolivas.org>
Cc: linux-kernel@vger.kernel.org, Kirill Korotaev <dev@sw.ru>,
MAEDA Naoaki <maeda.naoaki@jp.fujitsu.com>,
akpm@osdl.org, ckrm-tech@lists.sourceforge.net
Subject: Re: [ckrm-tech] Re: [PATCH 0/9] CPU controller
Date: Fri, 28 Apr 2006 12:42:51 +0200 [thread overview]
Message-ID: <1146220971.17763.11.camel@homer> (raw)
In-Reply-To: <200604282026.39520.kernel@kolivas.org>
On Fri, 2006-04-28 at 20:26 +1000, Con Kolivas wrote:
> On Friday 28 April 2006 20:16, Mike Galbraith wrote:
> > > How many tasks? Your function was O(n) so the more tasks the longer that
> > > max value was.
> >
> > Nope. It's not O(tasks), it's O(occupied_queues). Occupied queues is
> > generally not a large number.
>
> Ok well that P4 does about 700,000 context switches per second so 4us sounds
> large to me.
I'm not always calling it now, only when necessary. In any case, I'd
much rather pay 4us (it averages 1) every 100ms when at 100% cpu than
take a multi-second latency hit for high priority tasks as now occurs
with a heavy load when the array switch is forced. This hit is more
likely with my (unfortunately necessary) change to wake tasks on the
expired array. That's why I started trying to eliminate the switch.
-Mike
next prev parent reply other threads:[~2006-04-28 10:42 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-28 1:37 MAEDA Naoaki
2006-04-28 1:37 ` [PATCH 1/9] CPU controller - Add class load estimation support MAEDA Naoaki
2006-04-28 1:37 ` [PATCH 2/9] CPU controller - Add class hungry detection support MAEDA Naoaki
2006-04-28 1:37 ` [PATCH 3/9] CPU controller - Add timeslice scaling support MAEDA Naoaki
2006-04-28 1:37 ` [PATCH 4/9] CPU controller - Add interface functions MAEDA Naoaki
2006-04-28 1:37 ` [PATCH 5/9] CPU controller - Documentation how the controller works MAEDA Naoaki
2006-04-28 1:38 ` [PATCH 6/9] CPU controller - Add basic functions and registering the controller MAEDA Naoaki
2006-04-28 1:38 ` [PATCH 7/9] CPU controller - Add routines to change share values and show stat MAEDA Naoaki
2006-04-28 1:38 ` [PATCH 8/9] CPU controller - Add cpu hotplug support MAEDA Naoaki
2006-04-28 1:38 ` [PATCH 9/9] CPU controller - Documentation how to use the controller MAEDA Naoaki
2006-04-28 5:25 ` [PATCH 0/9] CPU controller Mike Galbraith
2006-04-28 5:48 ` MAEDA Naoaki
2006-04-28 6:59 ` Mike Galbraith
2006-04-28 7:26 ` MAEDA Naoaki
2006-04-28 7:41 ` Mike Galbraith
2006-04-28 7:56 ` [ckrm-tech] " MAEDA Naoaki
2006-04-28 9:29 ` Mike Galbraith
2006-04-28 10:01 ` Mike Galbraith
2006-04-28 10:11 ` Con Kolivas
2006-04-28 12:07 ` MAEDA Naoaki
2006-04-28 13:09 ` Con Kolivas
2006-04-28 13:55 ` Hirokazu Takahashi
2006-04-28 14:55 ` Con Kolivas
2006-04-28 15:39 ` Mike Galbraith
2006-04-28 5:56 ` Kirill Korotaev
2006-04-28 7:11 ` Mike Galbraith
2006-04-28 7:46 ` Mike Galbraith
2006-04-28 8:13 ` Kirill Korotaev
2006-04-28 9:35 ` Mike Galbraith
2006-04-28 10:09 ` Con Kolivas
2006-04-28 10:16 ` Mike Galbraith
2006-04-28 10:26 ` Con Kolivas
2006-04-28 10:42 ` Mike Galbraith [this message]
2006-04-28 8:28 ` MAEDA Naoaki
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