1. thread switching time? (Krassimir Slavchev)
krassi at bulinfo.net
Mon Nov 3 03:15:27 PST 2008
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Julian Elischer wrote:
> Krassimir Slavchev wrote:
>> Also, I am able to set HZ=100000 but the thread switching time is still
> You must be talking about the time that a thread can run before it is
> pushed out by other threads? I know I've seem many x 10,000 context
> switches in some cases, i.e. look at very high interrupt rates
> etc. so I guess I'm not sure what you are measuring..
> at one time the scheduling quantum was independent of Hz.
> I am not sure how true that is now..
The scheduling quantum is independent of Hz for Hz > 1000.
if (hz > 1000)
tc_tick = (hz + 500) / 1000;
tc_tick = 1;
I am not sure whether setting Hz > 1000 impact on performance or not,
e.g using polling(4).
Removing this limitation and setting kern.hz=10000 give 100usec quantum.
Thanks for the point.
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