Date: Wed, 27 Aug 2003 21:25:56 -0500 (GMT)
Message-Id: <200308280225.h7S2PuM26198@webmail2.vsnl.net>
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From: warudkar@vsnl.net
To: kernel@kolivas.org, wli@holomorphy.com, linux-kernel@vger.kernel.org
Subject: RE:2.6.0-test4-mm1 - kswap hogs cpu OO takes ages to start!
Cc: Andrew Morton <akpm@osdl.org>
Sender: linux-kernel-owner@vger.kernel.org
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Con - With swappiness set to 100, the apps do start up in 3 minutes and kswapd doesn't hog the CPU. But X is still unusable till all of them have started up.
Wli - Sorry, vmstat segfaults on 2.6!

kernel@kolivas.org wrote
On Thu, 28 Aug 2003 07:38, warudkar@vsnl.net wrote:
> Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org, Rational
> Rose and Konsole at a time. All of these take extremely long time to
> startup. (approx > 5 minutes). Kswapd hogs the CPU all the time. X becomes
> unusable till all of them startup, although I can telnet and run top. Same
> thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd
> never take more than 2% CPU.

Yes I can reproduce this with a memory heavy load as well on low memory 
(linking at the end of a big kernel compile is standard problem). I actually 
found the best workaround was to increase the swappiness instead of 
decreasing it.

Try 
echo 100 > /proc/sys/vm/swappiness

time it

then try
echo 0 > /proc/sys/vm/swappiness

you'll see that at low swappiness kswapd0 can use ridiculous amounts of cpu 
trying to avoid swap. The default is 60.

Con
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