linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: thockin@hockin.org
To: Lee Revell <rlrevell@joe-job.com>
Cc: linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: Dual core Athlons and unsynced TSCs
Date: Fri, 13 Jan 2006 10:16:31 -0800	[thread overview]
Message-ID: <20060113181631.GA15366@hockin.org> (raw)
In-Reply-To: <1137175117.15108.18.camel@mindpipe>

On Fri, Jan 13, 2006 at 12:58:36PM -0500, Lee Revell wrote:
> > If your BIOS has an ACPI "HPET" table, then the kernel can use the HPET
> > timer instead.  It doesn't solve the problem for apps or other kernel bits
> > that use rdtsc directly, but there are other fixes for that floating
> > around which will hopefully get consideration when they're mature.
> 
> The apps can be converted to use clock_gettime(), but that does not help
> if the kernel can't keep reasonable time on these machines. 

Some apps/users need higher resolution and lower overhead that only rdtsc
can offer currently.

> But if we just use "clock=pmtmr" by default on these machines the TSC is
> not a problem right?

I never tried it with pmtimer, we had HPET available.  Empirically TSC did
not work (and we had a simple test case to show how bad it could get).
HPET made that go away for users of gettimeofday().

We're exploring rdtsc-compatible solutions.

  reply	other threads:[~2006-01-13 18:06 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-12 22:17 Dual core Athlons and unsynced TSCs Lee Revell
2006-01-13 15:10 ` Roger Heflin
2006-01-13 16:04   ` Steven Rostedt
2006-01-13 17:47     ` Lee Revell
2006-01-13 17:52       ` Steven Rostedt
2006-01-13 17:54         ` Lee Revell
2006-01-13 18:41           ` Steven Rostedt
2006-01-13 18:55             ` Lee Revell
2006-01-13 20:09               ` Steven Rostedt
2006-01-13 20:26                 ` Steven Rostedt
2006-01-13 20:40                   ` Lee Revell
2006-01-13 20:43                   ` Lee Revell
2006-01-13 20:46                     ` Thomas Gleixner
2006-01-13 20:48                       ` Lee Revell
2006-01-13 20:51                         ` Thomas Gleixner
2006-01-13 20:52                         ` Steven Rostedt
2006-01-13 21:05                       ` Steven Rostedt
2006-01-13 21:10                         ` Thomas Gleixner
2006-01-13 21:17                           ` Steven Rostedt
2006-01-16  9:52                             ` Thomas Gleixner
2006-01-16 15:55                               ` Steven Rostedt
2006-01-14  0:23                 ` john stultz
2006-01-14  1:10                   ` Steven Rostedt
2006-01-14  1:14                     ` Lee Revell
2006-01-14  1:23                       ` john stultz
2006-01-14  1:27                         ` Lee Revell
2006-01-14  1:39                           ` john stultz
2006-01-14  1:43                             ` Steven Rostedt
2006-01-14  1:50                               ` john stultz
2006-01-14  2:15                                 ` Steven Rostedt
2006-01-14  2:34                                 ` Steven Rostedt
2006-01-16  1:19                             ` Andi Kleen
2006-01-14  6:54               ` Christoph Lameter
2006-01-13 18:06 ` thockin
2006-01-13 17:58   ` Lee Revell
2006-01-13 18:16     ` thockin [this message]
2006-01-13 18:09       ` Lee Revell
2006-01-13 18:55         ` thockin
2006-01-13 18:56           ` Sven-Thorsten Dietrich
2006-01-13 19:00             ` Lee Revell
2006-01-13 19:07               ` Sven-Thorsten Dietrich
2006-01-13 21:18               ` David Lang
2006-01-13 21:56                 ` thockin
2006-01-13 22:05                   ` David Lang
2006-01-13 22:18                     ` Sven-Thorsten Dietrich
2006-01-13 22:49                       ` David Lang
2006-01-14  0:41                         ` Andreas Steinmetz
2006-01-14  1:04                           ` David Lang
2006-01-14  1:21                             ` Andreas Steinmetz
2006-01-14  1:51                               ` thockin
2006-01-15  8:52                             ` Zan Lynx
2006-01-15 16:25                               ` thockin
2006-01-15 16:33                                 ` Lee Revell
2006-01-15 18:21                                   ` thockin
2006-01-15 18:29                                     ` Lee Revell
2006-01-15 18:49                                       ` thockin
2006-01-14  1:13                           ` thockin
2006-01-13 22:23                     ` thockin
2006-01-13 19:13             ` Xavier Bestel
2006-01-13 19:32             ` thockin
2006-01-13 20:58               ` Steven Rostedt
     [not found] <5ujmj-1UQ-511@gated-at.bofh.it>
     [not found] ` <5uBnF-2SG-11@gated-at.bofh.it>
     [not found]   ` <5uBnF-2SG-9@gated-at.bofh.it>
     [not found]     ` <5uBxi-3iM-21@gated-at.bofh.it>
     [not found]       ` <5uBGY-3ul-21@gated-at.bofh.it>
     [not found]         ` <5uCa5-443-45@gated-at.bofh.it>
     [not found]           ` <5uCjF-4fW-15@gated-at.bofh.it>
     [not found]             ` <5uCtj-4Fi-15@gated-at.bofh.it>
2006-01-14  0:24               ` Robert Hancock

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=20060113181631.GA15366@hockin.org \
    --to=thockin@hockin.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rlrevell@joe-job.com \
    /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).