From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Mich Lanners <mlan@cpu.lu>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: Clock running fast on Mac Mini?
Date: Tue, 25 Apr 2006 14:14:03 +1000 [thread overview]
Message-ID: <1145938443.29938.60.camel@localhost.localdomain> (raw)
In-Reply-To: <E1FY8kd-0000mH-PO@owl.grunz.lu>
On Mon, 2006-04-24 at 23:37 +0200, Mich Lanners wrote:
> Hello all,
>
> I have a problem on my Mac Mini with the kernel clock, which is running
> fast.
>
> In fact, it is gaining 10 ms every 5 seconds, as can be seen here, with
> ntpdate called every 5 seconds:
>
> owl:~# while true; do ntpdate -u be.pool.ntp.org; sleep 5; done
> 24 Apr 23:14:17 ntpdate[2601]: adjust time server 195.47.215.226 offset 0.151197 sec
> 24 Apr 23:14:22 ntpdate[2607]: adjust time server 195.47.215.226 offset 0.160348 sec
> 24 Apr 23:14:28 ntpdate[2613]: adjust time server 195.47.215.226 offset 0.170311 sec
> [...]
> 24 Apr 23:17:15 ntpdate[2813]: adjust time server 195.47.215.226 offset 0.489635 sec
> 24 Apr 23:17:20 ntpdate[2819]: adjust time server 195.47.215.226 offset 0.499386 sec
> 24 Apr 23:17:25 ntpdate[2825]: step time server 195.47.215.226 offset 0.509342 sec
> 24 Apr 23:17:31 ntpdate[2831]: adjust time server 195.47.215.226 offset 0.013693 sec
> 24 Apr 23:17:36 ntpdate[2837]: adjust time server 195.47.215.226 offset 0.021668 sec
>
> and so on.
>
> This is with ntpd stopped, after a fresh boot with /etc/adjtime removed
> to make sure hwclock is not falsly tuning the kernel timekeeping (I did
> this because I once had a 2.6.16 kernel running, where clock problems
> have been reported. I thought that may have falsified ntp's drift file
> and/or hwclock's /etc/adjtime).
>
> All this is with a 2.6.15 kernel.
>
> My Alu powerbook with a 2.6.15 kernel does not show this problem.
Could be several things... the clock calibration data from the
device-tree incorrect, or a rouding bug we fixed recently... I'd expect
2.6.16 to be good.
Ben
prev parent reply other threads:[~2006-04-25 4:14 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-04-24 21:37 Clock running fast on Mac Mini? Mich Lanners
2006-04-24 22:06 ` Brent Cook
2006-04-25 4:14 ` Benjamin Herrenschmidt [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1145938443.29938.60.camel@localhost.localdomain \
--to=benh@kernel.crashing.org \
--cc=linuxppc-dev@ozlabs.org \
--cc=mlan@cpu.lu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).