Subject: Re: Can context switches be faster?
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Andreas Mohr <andi@rhlx01.fht-esslingen.de>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
       John Richard Moser <nigelenki@comcast.net>,
       Chris Friesen <cfriesen@nortel.com>, linux-kernel@vger.kernel.org
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Date: Sat, 14 Oct 2006 01:30:12 +0100
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Ar Sad, 2006-10-14 am 01:32 +0200, ysgrifennodd Andreas Mohr:
> OK, so since we've now amply worked out in this thread that TLB/cache flushing
> is a real problem for context switching management, would it be possible to
> smartly reorder processes on the runqueue (probably works best with many active
> processes with the same/similar priority on the runqueue!) to minimize
> TLB flushing needs due to less mm context differences of adjacently scheduled
> processes?

We already do. The newer x86 processors also have TLB tagging so they
can (if you find one without errata!) avoid the actual flush and instead
track the tag.

Alan
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