Re: Bug with shared memory.

Andrea Arcangeli (andrea@suse.de)
Mon, 20 May 2002 18:37:24 +0200


On Mon, May 20, 2002 at 09:13:53AM -0700, Martin J. Bligh wrote:
> Is it really the rmap patch, or is this Alan's VM as a whole?
> Could you take a look at http://www.surriel.com/patches/ and
> see if the rmap 13 patch there is still objectionable to you?

I think it's almost the same code.

> I've been benchmarking rmap 13 against mainline (2.4.19-pre7)
> and with the latest lock breakup changes performance now seems
> to be about equivalent to mainline (for kernel compile on NUMA-Q).
> Those changes reduced system time from 650s to 160s. The only

How much are you swapping in your workload? (as said the fast paths are
hurted a little so it's expected that it's almost as fast as mainline
with a kernel compile, similar to the fact we also add anon pages to the
lru list). I think you're only exercising the fast paths in your
workload, not the memory balancing that is the whole point of the change.

> reason I haven't published results "officially" yet is that I
> was sorting out some timer problems with the machine.
>
> M.

Andrea
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