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From: Pavel Machek <pavel@ucw.cz>
To: Simon Arlott <simon@fire.lp0.eu>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	akpm@linux-foundation.org, arjan@linux.intel.com
Subject: Re: [PATCH (updated)] timer: Run calc_load halfway through each round_jiffies second
Date: Tue, 1 Jan 2002 03:05:07 +0000	[thread overview]
Message-ID: <20020101030506.GB4106@ucw.cz> (raw)
In-Reply-To: <45E75911.3070907@simon.arlott.org.uk>

Hi!

> Whenever jiffies is started at a multiple of 5*HZ or 
> wraps, calc_load is run exactly on the second which is 
> when tasks using round_jiffies will be scheduled to run. 
> This has a bad effect on the load average, making it 
> tend towards 1.00 if a task happens to run every time 
> the load is being calculated.
> 
> This changes calc_load so that it updates load half a 
> second after any tasks scheduled using round_jiffies.

Hmm, otoh this makes calc_load more expensive, power-wise, because it
needs to wake the cpu once more?

Timetraveling, sorry.
						Pavel
-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

  reply	other threads:[~2007-03-05 21:38 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-24 15:19 round_jiffies and load average Simon Arlott
2007-03-01  9:11 ` Simon Arlott
2007-03-01 18:52   ` [PATCH] timer: Add an initial 0.5s delay to calc_load Simon Arlott
2007-03-01 22:52     ` [PATCH (updated)] timer: Run calc_load halfway through each round_jiffies second Simon Arlott
2002-01-01  3:05       ` Pavel Machek [this message]
2007-03-05 22:35         ` Simon Arlott
2007-03-06 18:42           ` [PATCH (update 4)] " Simon Arlott
2007-03-06 22:20         ` [PATCH (updated)] " Chuck Ebbert
2007-03-01 23:10       ` Bill Irwin
2007-03-02 10:15         ` [PATCH (update 2)] " Simon Arlott
2007-03-02 15:15           ` [PATCH (update 3)] " Simon Arlott
2007-03-02 16:35             ` Eric Dumazet
2007-03-02 17:32               ` Simon Arlott
2007-03-02 18:03                 ` Eric Dumazet
2007-03-02 20:14                   ` Simon Arlott
2007-03-02 22:32                     ` Eric Dumazet
2007-03-02 23:54                       ` Simon Arlott

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