Horton

Re: First set of OSDL Shared Mem scalability results, some

Curt Sampson <cjs@cynic.net>

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From: Curt Sampson <cjs@cynic.net>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Kevin Brown <kevin@sysexperts.com>, pgsql-performance@postgresql.org
Date: 2004-10-24T05:46:16Z
Lists: pgsql-hackers, pgsql-performance 
On Sat, 23 Oct 2004, Tom Lane wrote:

> Seems to me the overhead of any such scheme would swamp the savings from
> avoiding kernel/userspace copies ...

Well, one really can't know without testing, but memory copies are
extremely expensive if they go outside of the cache.

> the locking issues alone would be painful.

I don't see why they would be any more painful than the current locking
issues. In fact, I don't see any reason to add more locking than we
already use when updating pages.

cjs
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Curt Sampson  <cjs@cynic.net>   +81 90 7737 2974   http://www.NetBSD.org
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