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Subject: Re: Change default VFS timestamp precision?
In-reply-to: <77322.1418933100@critter.freebsd.dk>
From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
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Date: Thu, 18 Dec 2014 20:14:02 +0000
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Cc: "freebsd-arch@freebsd.org" <arch@freebsd.org>,
 Adrian Chadd <adrian@freebsd.org>, Jilles Tjoelker <jilles@stack.nl>
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--------
In message <77322.1418933100@critter.freebsd.dk>, "Poul-Henning Kamp" writes:

>>I don't understand
>>why you think TSP_USEC is slower than TSP_NSEC.  microtime() and nanotime()
>>both just call bintime() and then convert the result using similar math.
>
>Because of the pointless nano->micro conversion which makes TSP_USEC
>take a division longer to deliver a less precise result than TSP_NSEC.

Actually, that's the other way around: it converts microseconds to
nanoseconds with a pointless multiplication.

-- 
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.