From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: Re: possible time_interpolator bug?
Date: Wed, 18 Feb 2004 06:58:06 +0000 [thread overview]
Message-ID: <16435.3326.193311.110598@napali.hpl.hp.com> (raw)
In-Reply-To: <1077086574.985.56.camel@cog.beaverton.ibm.com>
>>>>> On Tue, 17 Feb 2004 22:42:54 -0800, john stultz <johnstul@us.ibm.com> said:
John> So each second, we call "_update(NSEC_PER_SEC)", however for
John> each tick we call update_wall_time_one_tick() which calls
John> "_update(delta_nsec)".
John> Thus in a period of one second, we call _update() HZ times w/
John> ~NSEC_PER_SEC/HZ as an argument, then at the second overflow
John> we call it again w/ NSEC_PER_SEC.
John> It seems that calling _update() on the second overflow is
John> unnecessary.
Not just unnecessary, but wrong!
John> It would be noted that time inconsistencies are not seen using
John> the ITC interpolator, however the ITC interpolator has an
John> empty _update function.
Yes.
John> Am I just missing something here?
I don't think so. Good bug hunting. Some time ago SGI reported some
jumpiness but I never got a definite answer whether the problem had
been solved.
You may want to run this by someone who actually understands the code
in timer.c but I'm pretty sure you're right.
Thanks,
--david
next prev parent reply other threads:[~2004-02-18 6:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-02-12 3:22 [RFC][PATCH] linux-2.6.3-rc2_ia64-cyclone_A0 john stultz
2004-02-13 0:14 ` David Mosberger
2004-02-13 1:05 ` john stultz
2004-02-13 1:16 ` David Mosberger
2004-02-13 1:41 ` Chris McDermott
2004-02-13 2:07 ` David Mosberger
2004-02-13 2:29 ` john stultz
2004-02-13 7:09 ` David Mosberger
2004-02-13 18:55 ` Mallick, Asit K
2004-02-17 2:46 ` john stultz
2004-02-17 21:41 ` David Mosberger
2004-02-18 5:20 ` [RFC][PATCH] linux-2.6.3-rc2_ia64-cyclone_A1 john stultz
2004-02-18 6:42 ` possible time_interpolator bug? john stultz
2004-02-18 6:58 ` David Mosberger [this message]
2004-02-23 19:44 ` [PATCH] linux-2.6.3_time-interpolator-fix_A0 john stultz
2004-02-23 19:55 ` David Mosberger
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=16435.3326.193311.110598@napali.hpl.hp.com \
--to=davidm@napali.hpl.hp.com \
--cc=linux-ia64@vger.kernel.org \
/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