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To: David Xu <davidxu@freebsd.org>
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In-Reply-To: Your message of "Fri, 28 Oct 2005 21:25:03 +0800."
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Date: Fri, 28 Oct 2005 16:16:22 +0200
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Cc: Pertti Kosunen <pertti.kosunen@pp.nic.fi>, ticso@cicely.de,
	"Yuriy N. Shkandybin" <jura@networks.ru>, current@freebsd.org
Subject: Re: Timers and timing, was: MySQL Performance 6.0rc1 
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In message <436226AF.10109@freebsd.org>, David Xu writes:

>That's just an idea. :-)
>As robert said, add a lower resolution CLOCK_ type  may work well.
>Another thing I just though of, if reading timercounter is so slow, won't
>gettimeofday hardly block cpu too many cycles ? the cpu is just stucked
>there by a slow clock in hardware signals.

The get*() family of functions just copy a timestamp, they go nowhere
near hardware.  So they are fast, but less precise (~ 1 msec).

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.