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Date: Tue, 3 Feb 2004 11:08:11 -0800 (PST)
From: Matthew Dillon <dillon@apollo.backplane.com>
Message-Id: <200402031908.i13J8BAP003708@apollo.backplane.com>
To: Robert Watson <rwatson@freebsd.org>
References: <Pine.NEB.3.96L.1040203121006.79056G-100000@fledge.watson.org>
cc: Dag-Erling =?iso-8859-1?q?Sm=F8rgrav?= <des@des.no>
cc: current@freebsd.org
Subject: Re: Coalescing pipe allocation
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:...
:Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
:robert@fledge.watson.org      Senior Research Scientist, McAfee Research

    It seems to me that realizing the lion's share of the benefit requires 
    only that you cache the KVM reservation for a pipe buffer, and that
    you perhaps separately cache pipe meta data structures.  I think
    you would only get a smidgen more performance by caching the entire
    pipe pair, so it seems a bit overkill to do that.  By my quick read it
    looks like it would be trivial to create a small per-cpu (UMA based for
    you guys, globaldata based for me) cache.  A hysteresis of 4 ought to
    be sufficient.

					-Matt
					Matthew Dillon 
					<dillon@backplane.com>