From: Jonathan Larmour <jlarmour@redhat.com>
To: Andrea Acquaviva <aacquaviva@deis.unibo.it>
Cc: "ecos-discuss@sources.redhat.com" <ecos-discuss@sources.redhat.com>
Subject: Re: [ECOS]thread switch frequency
Date: Fri, 20 Apr 2001 02:23:00 -0000 [thread overview]
Message-ID: <3AE00009.2BC3F600@redhat.com> (raw)
In-Reply-To: <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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prev parent reply other threads:[~2001-04-20 2:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-04-20 1:59 Andrea Acquaviva
2001-04-20 2:23 ` Jonathan Larmour [this message]
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