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Date: Thu, 17 May 2007 14:43:16 +0200
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: Re: [Xenomai-core] [PATCH] Use tsc for implementation of
	clock_gettime.
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To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: xenomai@xenomai.org

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Gilles Chanteperdrix wrote:
> Hi,
>=20
> here comes, for review, a patch which reduces the overhead of
> clock_gettime by directly reading the tsc in user-space for
> architectures that support it.

Highly welcome. But I have one concern: How and when do you propagate
wallclock_offset changes to user space?

I think we need some vsyscall-alike approach for this, some read-only
page that is mapped into every RT process, containing things like a
regularly updated offset (seqlock fashioned) or other read-only
information (shadow mode? cpu id?).

Jan


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