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Re: thread switch frequency
- To: Andrea Acquaviva <aacquaviva at deis dot unibo dot it>
- Subject: Re: [ECOS]thread switch frequency
- From: Jonathan Larmour <jlarmour at redhat dot com>
- Date: Fri, 20 Apr 2001 10:23:21 +0100
- Cc: "ecos-discuss at sources dot redhat dot com" <ecos-discuss at sources dot redhat dot com>
- Organization: Red Hat UK Ltd.
- References: <3ADFFA65.CC964CFF@deis.unibo.it>
Andrea Acquaviva wrote:
>
> Hi,
> I have a question about eCos mlqueue scheduler.
> If there are two threads (making a matrix multiplication), running with
> the same priority, they switch with a frequency given by:
>
> f_clock/CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS,
>
> where f_clock in the case of strongarm1110 (assabet) is 3.6864MHz.
>
> Is this correct or is there something else that affects the switching
> frequency?
The timer that drives the kernel clock interrupt is at 3.6864MHz yes, but
it is has been programmed to only actually interrupt when its counter
reaches 36864, which corresponds to every 10ms. And only 1 in
CYGNUM_KERNEL_SCHED_TIMESLICE_TICKS of those causes a timeslice.
Jifl
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