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From: des@des.no (Dag-Erling =?iso-8859-1?Q?Sm=F8rgrav?=)
To: David G Lawrence <dg@dglawrence.com>
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Date: Tue, 24 Apr 2007 15:46:28 +0200
In-Reply-To: <20070424042102.GI38475@tnn.dglawrence.com> (David G. Lawrence's
	message of "Mon, 23 Apr 2007 21:21:02 -0700")
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Cc: Tim Kientzle <kientzle@freebsd.org>, current@freebsd.org,
	"Jesper B. Rosenkilde" <jbr@humppa.dk>
Subject: Re: Suggestions on Avoiding syscall Overhead
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David G Lawrence <dg@dglawrence.com> writes:
> gettimeofday(2) returns microsecond precision, so I don't see how this
> could be made accelerated via a mapped global page. time(3) [which is
> currently a wrapper for gettimeofday(2)], on the other had, could be put
> into such a page since it only updates once a second.

gettimeofday(2) returns a value in microseconds, but this does not
necessarily mean that it has microsecond precision.  Updating it once
per scheduler tick or once per context switch (in userret(), for
instance) is probably enough.

DES
--=20
Dag-Erling Sm=F8rgrav - des@des.no