Re: [PATCH 3/4] add ksm kernel shared memory driver

From: Izik Eidus
Date: Tue Nov 11 2008 - 18:03:39 EST


Jonathan Corbet wrote:

What about things like cache effects from scanning all those pages? My
guess is that, if you're trying to run dozens of Windows guests, cache
usage is not at the top of your list of concerns, but I could be
wrong. Usually am...

Ok, ksm does make the cache of the cpu dirty when scanning the pages
(but the scanning happen slowly slowly and cache usually get dirty much faster)
But infact it improve the cache by the fact that it make many ptes point to the same page
so if before we had 12 process touching 12 diffrent physical page they would dirty the page
but now they will touch just one...

so i guess it depend on how you see it...

Thanks,

jon

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