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Date: Thu, 10 Jan 2002 15:04:59 -0800 (PST)
From: Davide Libenzi <davidel@xmailserver.org>
X-X-Sender: davide@blue1.dev.mcafeelabs.com
To: Ingo Molnar <mingo@elte.hu>
cc: Mike Kravetz <kravetz@us.ibm.com>, Linus Torvalds <torvalds@transmeta.com>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        Anton Blanchard <anton@samba.org>, george anzinger <george@mvista.com>,
        Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [patch] O(1) scheduler, -G1, 2.5.2-pre10, 2.4.17 (fwd)
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On Fri, 11 Jan 2002, Ingo Molnar wrote:

> indeed. The question is, should we migrate processes around just to get
> 100% fairness in 'top' output? The (implicit) cost of a task migration
> (caused by the destruction & rebuilding of cache state) can be 10
> milliseconds easily on a system with big caches.

10 ms is exactly what i've observed while i was coding the BMQS balance
code. Leaving a cpu idle for more than 10ms will make real tests like
kernel builds to suffer performance degradation. By using 10ms i always
got the same time of the standard scheduler.




- Davide


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