Re: 2.5 page cache improvement idea

[Andrea Arcangeli <andrea@suse.de>]

On Mon, Feb 26, 2001 at 07:26:18PM -0800, Gerrit Huizenga wrote:
> If you are considering NUMA architectures as a case of frequently
> accesses pages, e.g. glibc or text pages of commonly used executables,
> it is probably better to do page replication per node on demand than
> to worry about optimizing the page lookups for limited bus traffic.
> 
> Most NUMA machines are relatively rich in physical memory, and cross
> node traffic is relatively expensive.  As a result, wasting a small
> number of physical pages on duplicate read-only pages cuts down node
> to node traffic in most cases.  Many NUMA systems have a cache for
> remote memory (some cache only remote pages, some cache local and remote
> pages in the same cache - icky but cheaper).  As that cache cycles,
> it is cheaper to replace read-only text pages from the local node
> rather than the remote.  So, for things like kernel text (e.g. one of
> the SGI patches) and for glibc's text, as well as the text of other
> common shared libraries, it winds up being a significant win to replicate
> those text pages (on demand!) in local memory.

Agreed.

Andrea
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