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From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Jim Houston <jim.houston@attbi.com>
Cc: linux-kernel@vger.kernel.org,
	high-res-timers-discourse@lists.sourceforge.net,
	jim.houston@ccur.com
Subject: Re: [PATCH] improved boot time TSC synchronization
Date: Thu, 16 Jan 2003 21:33:32 +0000	[thread overview]
Message-ID: <20030116213332.GA14040@bjl1.asuk.net> (raw)
In-Reply-To: <200301161644.h0GGitX02052@linux.local>

Jim Houston wrote:
> + *	t0 ---\
> + *             ---\
> + *		   --->
> + *			tm
> + *		   /---
> + *	       /---
> + *	t1 <---
> + *
> + *
> + * The goal is to adjust the slave's TSC such that tm falls exactly half-way
> + * between t0 and t1.

It looks like not only can you synchronise with a certain accuracy,
you can determine an upper bound on that accuracy (assuming the
underlying CPU clocks are locked).

Maybe that figure could be put into /proc/cpuinfo?

As well as being an interesting value, it may be useful for programs
to know the effective accuracy of `rdtsc'.

-- Jamie

  parent reply	other threads:[~2003-01-16 21:25 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-01-16 16:44 [PATCH] improved boot time TSC synchronization Jim Houston
2003-01-16 17:54 ` David Mosberger
2003-01-16 21:33 ` Jamie Lokier [this message]
2003-01-17  0:34   ` Jim Houston
2003-01-17  1:00     ` Jamie Lokier
2003-01-17  3:35       ` Jim Houston
  -- strict thread matches above, loose matches on Subject: below --
2003-01-21  1:21 Jim Houston

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