Thread (7 messages) 7 messages, 2 authors, 2001-01-18

Re: Subtle MM bug

From: Rik van Riel <hidden>
Date: 2001-01-18 01:32:22
Also in: lkml

On 17 Jan 2001, Zlatko Calusic wrote:
Rik van Riel [off-list ref] writes:
quoted
quoted
Second test: kernel compile make -j32 (empirically this puts the
VM under load, but not excessively!)

2.2.17 -> make -j32  392.49s user 47.87s system 168% cpu 4:21.13 total
2.4.0  -> make -j32  389.59s user 31.29s system 182% cpu 3:50.24 total

Now, is this great news or what, 2.4.0 is definitely faster.
One problem is that these tasks may be waiting on kswapd when
kswapd might not get scheduled in on time. On the one hand this
will mean lower load and less thrashing, on the other hand it
means more IO wait.
Hm, if all tasks are waiting for memory, what is stopping kswapd
to run? :)
Suppose you have 8 high-priority tasks waiting on kswapd
and one lower-priority (but still higher than kswapd)
process running and preventing kswapd from doing its work.
Oh .. and also preventing the higher-priority tasks from
being woken up and continuing...


Rik
--
Virtual memory is like a game you can't win;
However, without VM there's truly nothing to lose...

		http://www.surriel.com/
http://www.conectiva.com/	http://distro.conectiva.com.br/

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