Re: Timers and timing, was: MySQL Performance 6.0rc1

From: Bernd Walter <ticso_at_cicely12.cicely.de>
Date: Fri, 28 Oct 2005 14:58:28 +0200
On Fri, Oct 28, 2005 at 06:43:10PM +0800, David Xu wrote:
> Poul-Henning Kamp wrote:
> >In message <4361FDBE.7000500_at_freebsd.org>, David Xu writes:
> >
> >
> >the correct way to optimize this would be to add a time(2) systemcall
> >which returns the value of the kernel global time_second.
> >
> 
> Can we make a page in kernel address space which is readable my user
> code? put the variable in the page, I know read an integer is atomic-op,
> needn't lock, so syscall is not needed.

Don't whink it is importent for 1s intervalls, but atomic != coherent.

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd_at_bwct.de                                  info_at_bwct.de
Received on Fri Oct 28 2005 - 11:12:50 UTC

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