From: Hugh Dickins <hugh@veritas.com>
To: David Brownell <david-b@pacbell.net>
Cc: Matt Mackall <mpm@selenic.com>,
Philippe De Muyter <phdm@macqel.be>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: RTC subsystem and fractions of seconds
Date: Sun, 7 Jan 2007 01:11:43 +0000 (GMT) [thread overview]
Message-ID: <Pine.LNX.4.64.0701070108001.1428@blonde.wat.veritas.com> (raw)
In-Reply-To: <200701061552.43654.david-b@pacbell.net>
On Sat, 6 Jan 2007, David Brownell wrote:
> On Saturday 06 January 2007 3:26 pm, Philippe De Muyter wrote:
>
> > The way it is done currently
> > in drivers/rtc/hctosys.c is 0.5 sec off. We could obtain a much better
> > precision by looping there until the next change (next second for old clocks,
> > next 0.01 second for m41t81, maybe even better for other ones).
>
> Hmm ... "looping" fights against "quickly"; as would "wait for next
> update IRQ" (on RTCs that support that). But it would improve precision,
> at least in the sense of having the system clock and that RTC spending
> less time with the lowest "seconds" digit disagreeing.
>
> This is something you could write a patch for, n'est-ce pas?
If you're thinking of going that way, it'd be courteous to CC Matt,
who devoted some effort to removing just that loop in 2.6.17 ;)
Hugh
next prev parent reply other threads:[~2007-01-07 1:11 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-06 3:49 David Brownell
2007-01-06 23:26 ` Philippe De Muyter
2007-01-06 23:52 ` David Brownell
2007-01-07 1:11 ` Hugh Dickins [this message]
2007-01-07 2:54 ` David Brownell
2007-01-07 9:43 ` Hugh Dickins
2007-01-07 10:02 ` Philippe De Muyter
2007-01-07 10:14 ` Philippe De Muyter
2007-01-08 2:10 ` David Brownell
2007-01-08 10:25 ` Philippe De Muyter
-- strict thread matches above, loose matches on Subject: below --
2007-01-07 22:31 Philippe De Muyter
2007-01-06 2:29 Philippe De Muyter
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