Re: select returning slow on RH 2.4.18-14 (RH 8.0) kernel.

From: Arjan van de Ven (arjanv@redhat.com)
Date: Thu Feb 13 2003 - 06:39:00 EST


On Thu, 2003-02-13 at 10:08, Ben Greear wrote:
> I've been doing some testing with RH 8.0 on an Ezra 800Mhz
> machine.
>
> Even when lightly loaded select() often returns 3-9 miliseconds slower
> than the timeout would suggest. I know select is not guaranteed to
> return with < 10ms accuracy, but with almost no load, shouldn't it
> at least return with 1ms accuracy on average?
no
the kernel.org kernels will return in multiple-of-10ms quantities due to
HZ having the value of 100.
2.4.18-14 (which is btw obsoleted by several security errata) has a HZ
value of 512 so will return in shorter quantities, EXCEPT when you
always try to wait exactly 10ms of course....



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