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From: Chris Friesen <cfriesen@nortelnetworks.com>
To: Rik van Riel <riel@conectiva.com.br>
Cc: Mark Mielke <mark@mark.mielke.cc>,
	Terje Eggestad <terje.eggestad@scali.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Liam Girdwood <l_girdwood@bitwise.co.uk>,
	BALBIR SINGH <balbir.singh@wipro.com>,
	William Olaf Fraczyk <olaf@navi.pl>,
	Lee Irwin III <wli@holomorphy.com>
Subject: Re: Why HZ on i386 is 100 ?
Date: Tue, 16 Apr 2002 12:12:11 -0400	[thread overview]
Message-ID: <3CBC4D5B.C7EF2C8C@nortelnetworks.com> (raw)
In-Reply-To: <Pine.LNX.4.44L.0204161231440.16531-100000@duckman.distro.conectiva>

Rik van Riel wrote:
> 
> On Tue, 16 Apr 2002, Mark Mielke wrote:
> 
> > Increasing the HZ can only improve responsiveness, however, there is a
> > cost (mentioned by others). The cost is that the scheduler is executed
> > more often per second. If the scheduler does the same amount of work
> > per tick, but there are more ticks per second, the scheduler does more
> > work overall, and the CPU is free for use by the processes less.
> 
> Why are you discussing Linux 1.2 ?
> 
> Linux is not running the scheduler each cpu tick and hasn't
> done this for years.

Very true.  However it does run the timer/clock code every tick, which is still
additional overhead when the tick time is reduced.

The basic idea (increased overhead at higher HZ) is sound, the details are not.

Chris

-- 
Chris Friesen                    | MailStop: 043/33/F10  
Nortel Networks                  | work: (613) 765-0557
3500 Carling Avenue              | fax:  (613) 765-2986
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  reply	other threads:[~2002-04-16 16:03 UTC|newest]

Thread overview: 75+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-04-16  7:47 Why HZ on i386 is 100 ? Olaf Fraczyk
2002-04-16  8:14 ` William Lee Irwin III
2002-04-16  8:18   ` BALBIR SINGH
2002-04-16 10:29     ` Liam Girdwood
2002-04-16 10:01       ` Olaf Fraczyk
2002-04-16 13:35         ` Terje Eggestad
2002-04-16 13:38           ` Mark Mielke
2002-04-16 13:55             ` Terje Eggestad
2002-04-16 15:32             ` Rik van Riel
2002-04-16 16:12               ` Chris Friesen [this message]
2002-04-16 17:12               ` Mark Mielke
2002-04-16 13:58           ` Alan Cox
2002-04-17  0:22             ` H. Peter Anvin
2002-04-16 16:27         ` Linus Torvalds
2002-04-16 16:50           ` David Mosberger
2002-04-16 17:18             ` Davide Libenzi
2002-04-16 17:52               ` David Mosberger
2002-04-16 18:10                 ` Davide Libenzi
2002-04-17  0:49               ` David Mosberger
2002-04-17  0:57                 ` Robert Love
2002-04-17  1:07                   ` Davide Libenzi
2002-04-17  5:18                   ` Mark Mielke
2002-04-17  5:34                     ` Linus Torvalds
2002-04-17  6:01                       ` Robert Love
2002-04-17  6:17                         ` David Mosberger
2002-04-17  7:59                         ` arjan
2002-04-17  8:04                         ` Matti Aarnio
2002-04-23 22:42                           ` Albert D. Cahalan
2002-04-17 10:12                       ` Martin Dalecki
2002-04-18  1:51                   ` Dan Mann
2002-04-17  1:22                 ` Davide Libenzi
2002-04-17  3:19                 ` Ben Greear
2002-04-17  7:55                 ` Helge Hafting
2002-04-21 18:00                 ` Pavel Machek
2002-04-22 17:20                   ` John Alvord
2002-04-22 21:52                     ` george anzinger
2002-04-22 23:06                       ` J.D. Bakker
2002-04-22 23:26                       ` Anton Blanchard
2002-04-23 19:03                         ` george anzinger
2002-04-23  7:08                       ` Alan Cox
2002-04-22 17:24                   ` David Mosberger
2002-04-16 12:42     ` Richard B. Johnson
2002-04-16 12:31   ` Richard B. Johnson
2002-04-16 14:04 ` Bill Davidsen
2002-04-16 21:34 ` bert hubert
2002-04-16 22:21   ` Andreas Dilger
2002-04-16 22:37     ` Herbert Xu
2002-04-16 22:56       ` Andreas Dilger
2002-04-17  0:34         ` J. Dow
2002-04-17  2:40         ` Herbert Xu
2002-04-17 12:44       ` Kent Borg
2002-04-17  8:28     ` please merge 64-bit jiffy patches. Was " bert hubert
2002-04-17 11:05       ` please merge 64-bit jiffy patches Tim Schmielau
2002-04-17 11:12         ` bert hubert
2002-04-17 12:33           ` Bill Davidsen
2002-04-17 12:42             ` bert hubert
2002-04-17 14:57               ` Bill Davidsen
2002-04-17 11:09       ` please merge 64-bit jiffy patches. Was Re: Why HZ on i386 is 100 ? Wakko Warner
  -- strict thread matches above, loose matches on Subject: below --
2002-04-16 10:41 Cabaniols, Sebastien
2002-04-17  0:33 Chen, Kenneth W
2002-04-17  1:02 ` Davide Libenzi
     [not found] <3CC4861C.F21859A6@mvista.com.suse.lists.linux.kernel>
     [not found] ` <E16zuPf-0007yD-00@the-village.bc.nu.suse.lists.linux.kernel>
2002-04-23  7:17   ` Andi Kleen
2002-04-23 19:09     ` george anzinger
2002-04-24  1:42       ` Alan Cox
2002-04-24 20:20         ` george anzinger
2002-04-27 20:26           ` Alan Cox
2002-04-28  6:02             ` george anzinger
2002-04-28  9:12               ` Alan Cox
2002-04-28 17:34                 ` george anzinger
2002-04-28 18:59                   ` Alan Cox
2002-04-28 21:50                     ` george anzinger
2002-04-29  0:14                       ` Alan Cox
2002-04-23 19:24     ` george anzinger
2002-04-23 19:35       ` Andi Kleen
2002-04-24 17:25         ` Maciej W. Rozycki

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