select(2) timeout precision

Viktor Vasilev viktor.vasilev at
Wed Nov 2 01:20:44 PST 2005

On Wed, Nov 02, 2005 at 01:31:39AM -0600, Mike Silbersack wrote:
> On Tue, 1 Nov 2005, Viktor Vasilev wrote:
> >With FreeBSD 5.4-RELEASE I almost constantly get ~20000 microseconds
> >delta. That is with 100HZ kernel on PIII 500MHz or Sempron 64 2800+
> Put kern.hz=1000 in /boot/loader.conf to kick it up to 1000Hz, that 
> should improve the accuracy a lot.

Indeed! That did the trick.

> The optimizations in the url someone else posted should probably be 
> integrated into FreeBSD, but moving to a higher Hz setting is a 
> necessity in either case.

I've read in the lists, that in -CURRENT 1000HZ and PREEMPTION are in
the GENERIC kernel. It'll be interesting to see how it performs
there. With 6.0 around the corner, I'll give it a try soon.

Thank you and Mihail Balikov for the pointers.

I think and think for months and years. Ninety nine times, the
conclusion is false. The hundredth time I am right.
                               -- Albert Einstein

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