Re: [PATCH] Recent VM fiasco - fixed

From: Kai Henningsen (kaih@khms.westfalen.de)
Date: Thu May 11 2000 - 02:16:00 EST


torvalds@transmeta.com (Linus Torvalds) wrote on 10.05.00 in <Pine.LNX.4.10.10005102204370.1155-100000@penguin.transmeta.com>:

> Note that the mmap002 test is avery bad performance test.
>
> Why?
>
> Because it's a classic "walk a large array in order" test, which means
> that the worst possible order to page things out in is LRU.
>
> So toreally speed up mmap002, the best approach is to try to be as non-LRU
> as possible, which is obviously the wrong thing to do in real life. So in
> that sense optimizing mmap002 is a _bad_ thing.

Well, not quite. The *best* thing would be to recognize the behaviour, and
adapt to it.

Of course, it's also the hardest.

MfG Kai

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