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Date: Tue, 28 Apr 2009 07:52:50 +0200
From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
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Subject: Re: [Xenomai-core] xenomai 2.5 rc1 timing computations.
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Gilles Chanteperdrix wrote:
> Hi,
> 
> currently, the situation is this:
> - the timing core uses an approximate value of the cpu frequency (using
> xnarch_llmulshft) to do conversions between tsc and ns;
> - the APIC timer reprogrammation still uses imuldiv, that is a more
> exact cpu frequency, coupled with an approximate APIC frequency
> (obtained from ipipe_request_tickdev), to do the conversion between tsc
> delays and APIC delays;
> - the posix skin uses llimd to do conversions between timespec and
> timeval structures and tsc values
> - the posix and native skins in user-space still use llimd to do
> conversions between ns and tsc (only if using tsc in user-space).
> 
> These are causes of unprecisions, I think we should fix this, though it

imprecisions.


-- 
					    Gilles.