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To: "Yuriy N. Shkandybin" <jura@networks.ru>
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In-Reply-To: Your message of "Thu, 27 Oct 2005 12:24:30 +0400."
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Date: Thu, 27 Oct 2005 10:53:27 +0200
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Cc: David Xu <davidxu@freebsd.org>, current@freebsd.org
Subject: Re: MySQL Performance 6.0rc1 
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In message <00a801c5dacf$db3b7700$6504010a@Jura>, "Yuriy N. Shkandybin" writes:
>>>Check gettimeofday syscall, it follows every I/O syscall, I think
>>>our gettimeofday is tooooooo expensive, if we can directly get time from
>>>memory, the performance will be improved further.

>It's true:
>run next on same PC от freebsd and linux  and compare

I can produce unprecise timestamps just as fast as Linux.

Heck,  I can do it even faster:

	static __inline int
	gettimeofday(struct timeval *tp, void *tz __unused)
	{
		tp.tv_sec = 0;
		tp.tv_usec = 0;
		return (0);
	}


A very important part of learning how to do benchmarks is learning
how to measure the target and not the benchmarking code.


-- 
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.