All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@osdl.org>
To: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>, Ingo Molnar <mingo@elte.hu>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC] HZ free ntp
Date: Wed, 20 Dec 2006 20:26:21 -0800	[thread overview]
Message-ID: <20061220202621.8e147b1d.akpm@osdl.org> (raw)
In-Reply-To: <1166579658.5594.6.camel@localhost>

On Tue, 19 Dec 2006 17:54:18 -0800
john stultz <johnstul@us.ibm.com> wrote:

> On Tue, 2006-12-19 at 17:32 -0800, john stultz wrote:
> > On Wed, 2006-12-13 at 21:40 +0100, Roman Zippel wrote:
> > > On Wed, 13 Dec 2006, john stultz wrote:
> > > > > You don't have to introduce anything new, it's tick_length that changes
> > > > > and HZ that becomes a variable in this function.
> > > >
> > > > So, forgive me for rehashing this, but it seems we're cross talking
> > > > again. The context here is the dynticks code. Where HZ doesn't change,
> > > > but we get interrupts at much reduced rates.
> > > 
> > > I know and all you have to change in the ntp and some related code is to
> > > replace HZ there with a variable, thus make it changable, so you can
> > > increase the update interval (i.e. it becomes 1s/hz instead of 1s/HZ).
> > 
> > Untested patch below. Does this vibe better with you are suggesting?
> 
> And here would be the follow on patch (again *untested*) for
> CONFIG_NO_HZ slowing the time accumulation down to once per second.

I'm still awaiting a final-looking version of this patch, fyi.

I don't understand whether this is a theoretical might-happen thing,
or if NTP problems have actually been observed in the field?

Either way, I'm sure the final changelog will clear that up ;)

  reply	other threads:[~2006-12-21  4:26 UTC|newest]

Thread overview: 86+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-12-05  4:40 -mm merge plans for 2.6.20 Andrew Morton
2006-12-05  4:56 ` Jeff Garzik
2006-12-05  5:41   ` Andrew Morton
2006-12-05  7:04     ` Jens Axboe
2006-12-05 15:00     ` Mark Lord
2006-12-06 19:19     ` Conke Hu
2006-12-06 19:26       ` Randy Dunlap
2006-12-06 19:40       ` Jeff Garzik
2006-12-06 22:36       ` Andrew Morton
2006-12-05  5:14 ` Paul Mackerras
2006-12-05  5:42   ` Andrew Morton
2006-12-05  5:53     ` Nick Piggin
2006-12-05  5:49   ` Nick Piggin
2006-12-05  8:36 ` Gautham R Shenoy
2006-12-05  8:47 ` Peter Zijlstra
2006-12-05 11:06 ` ext2 future [was Re: -mm merge plans for 2.6.20] Pavel Machek
2006-12-05 13:23 ` -mm merge plans for 2.6.20 John W. Linville
2006-12-05 14:27 ` Roman Zippel
2006-12-06  3:46   ` Horst Schirmeier
2006-12-05 16:02 ` Dave Jones
2006-12-12 17:49   ` Dave Jones
2006-12-19  5:20     ` Nick Piggin
2006-12-19  6:44       ` Dave Jones
2006-12-19  7:02         ` Nick Piggin
2007-01-07 17:36       ` page_mapcount(page) went negative Dave Jones
2007-01-10 23:53         ` Nick Piggin
2006-12-05 17:35 ` -mm merge plans for 2.6.20 James Simmons
2006-12-05 18:01   ` Andrew Morton
2006-12-05 18:25     ` James Simmons
2006-12-05 18:37       ` [PATCH] backlight sysfs change to the fbdev drivers James Simmons
2006-12-05 18:37         ` James Simmons
2006-12-05 19:43       ` -mm merge plans for 2.6.20 Andrew Morton
2006-12-05 19:59         ` James Simmons
2006-12-05 20:20           ` Andrew Morton
2006-12-05 21:34             ` James Simmons
2006-12-06 23:40               ` Andrew Morton
2006-12-07 14:31                 ` James Simmons
2006-12-05 20:40       ` Miguel Ojeda
2006-12-06 14:42         ` James Simmons
2006-12-05 19:18 ` Josef Sipek
2006-12-05 19:21   ` [PATCH 1/2] fsstack: Make fsstack_copy_attr_all copy inode size Josef Sipek
2006-12-05 19:22   ` [PATCH 2/2] fsstack: Fix up ecryptfs's fsstack usage Josef Sipek
2006-12-05 22:28     ` Andrew Morton
2006-12-05 22:38       ` Josef Sipek
2006-12-05 22:49         ` Andrew Morton
2006-12-05 23:16           ` Josef Sipek
2006-12-05 21:00 ` -mm merge plans for 2.6.20 Ingo Molnar
2006-12-05 21:17 ` -mm merge plans for 2.6.20, scheduler bits Ingo Molnar
2006-12-05 20:59   ` Siddha, Suresh B
2006-12-05 21:47     ` Ingo Molnar
2006-12-05 21:29   ` Miguel Ojeda
2006-12-06  2:59 ` -mm merge plans for 2.6.20 Roman Zippel
2006-12-06  4:30   ` Andrew Morton
2006-12-06  8:32     ` Thomas Gleixner
2006-12-06 12:54       ` Roman Zippel
2006-12-06 13:11         ` Ingo Molnar
2006-12-06 14:33           ` Roman Zippel
2006-12-06 15:22             ` Ingo Molnar
2006-12-06 16:42               ` Roman Zippel
2006-12-06 16:58                 ` Ingo Molnar
2006-12-06 16:59                 ` Ingo Molnar
2006-12-12 20:40             ` [RFC] HZ free ntp john stultz
2006-12-13  9:51               ` Ingo Molnar
2006-12-13 18:48                 ` john stultz
2006-12-13 13:47               ` Roman Zippel
2006-12-13 19:19                 ` john stultz
2006-12-13 20:40                   ` Roman Zippel
2006-12-20  1:32                     ` john stultz
2006-12-20  1:54                       ` john stultz
2006-12-21  4:26                         ` Andrew Morton [this message]
2007-01-01 18:29                         ` Roman Zippel
2007-01-02 19:46                           ` john stultz
2007-01-02 20:50                             ` john stultz
2007-01-06 16:56                               ` Roman Zippel
2007-01-22 19:27                         ` [patch] HZ-free NTP Ingo Molnar
2007-01-22 19:39                           ` Ingo Molnar
2007-01-01 16:27                       ` [RFC] HZ free ntp Roman Zippel
2007-01-02 19:42                         ` john stultz
2007-01-06 16:46                           ` Roman Zippel
2006-12-06 12:33     ` -mm merge plans for 2.6.20 Roman Zippel
2006-12-08 14:09 ` Stephen Smalley
2006-12-08 20:58   ` Andrew Morton
2006-12-10 15:07     ` Mimi Zohar
2006-12-09  9:30 ` Randy Dunlap
2006-12-09  9:44   ` Andrew Morton
2006-12-10 20:12     ` Randy Dunlap

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=20061220202621.8e147b1d.akpm@osdl.org \
    --to=akpm@osdl.org \
    --cc=johnstul@us.ibm.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@elte.hu \
    --cc=tglx@linutronix.de \
    --cc=zippel@linux-m68k.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.