Timers and timing, was: MySQL Performance 6.0rc1

[Bernd Walter]

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