From: Jan Kiszka <jan.kiszka@domain.hid>
To: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Cc: xenomai@xenomai.org
Subject: Re: [Xenomai-core] [PATCH] Use tsc for implementation of clock_gettime.
Date: Thu, 17 May 2007 14:43:16 +0200 [thread overview]
Message-ID: <464C4DE4.1040402@domain.hid> (raw)
In-Reply-To: <17996.15540.824415.263562@domain.hid>
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Gilles Chanteperdrix wrote:
> Hi,
>
> 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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next prev parent reply other threads:[~2007-05-17 12:43 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-05-17 11:29 [Xenomai-core] [PATCH] Use tsc for implementation of clock_gettime Gilles Chanteperdrix
2007-05-17 12:43 ` Jan Kiszka [this message]
2007-05-17 12:54 ` Gilles Chanteperdrix
2007-05-17 13:00 ` Jan Kiszka
2007-05-17 13:10 ` Gilles Chanteperdrix
2007-05-17 13:31 ` Jan Kiszka
2007-05-17 15:21 ` Gilles Chanteperdrix
2007-05-17 15:56 ` Gilles Chanteperdrix
2007-05-18 5:52 ` Jan Kiszka
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