mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: john stultz <johnstul@us.ibm.com>
To: Andi Kleen <ak@suse.de>
Cc: Andrew Morton <akpm@osdl.org>,
	lkml <linux-kernel@vger.kernel.org>,
	discuss@x86-64.org
Subject: Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs
Date: Mon, 19 Sep 2005 12:42:16 -0700	[thread overview]
Message-ID: <1127158937.3455.214.camel@cog.beaverton.ibm.com> (raw)
In-Reply-To: <20050919193105.GA12810@verdi.suse.de>

On Mon, 2005-09-19 at 21:31 +0200, Andi Kleen wrote:
> On Mon, Sep 19, 2005 at 12:16:43PM -0700, john stultz wrote:
> > 	This patch should resolve the issue seen in bugme bug #5105, where it
> > is assumed that dualcore x86_64 systems have synced TSCs. This is not
> > the case, and alternate timesources should be used instead.
> 
> 
> I asked AMD some time ago and they told me it was synchronized.
> The TSC on K8 is C state invariant, but not P state invariant,
> but P states always happen synchronized on dual cores.
> 
> So I'm not quite convinced of your explanation yet.

Would a litter userspace test checking the TSC synchronization maybe
shed additional light on the issue?

thanks
-john




  reply	other threads:[~2005-09-19 19:42 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-19 19:16 john stultz
2005-09-19 19:31 ` Andi Kleen
2005-09-19 19:42   ` john stultz [this message]
2005-09-19 19:49     ` [discuss] " Andi Kleen
2005-09-20 18:59       ` john stultz
2005-09-21  4:03         ` Daniel Jacobowitz
2005-09-21 15:15           ` Ray Bryant
2005-09-21 15:04             ` Andi Kleen
2005-09-21 15:46               ` Ray Bryant
2005-09-22  8:00                 ` Jonas Oreland
2005-09-21 20:17               ` Andrew Morton
2005-10-07 12:26 ` Vladimir B. Savkin
2005-10-07 12:31   ` Andi Kleen
2005-10-07 14:15     ` Vladimir B. Savkin
2005-10-07 14:21       ` [discuss] " Velu Erwan
2005-10-08 10:11     ` Vladimir B. Savkin
2005-10-10 18:03       ` john stultz
2005-10-10 18:12         ` Vladimir B. Savkin
2005-10-10 18:19           ` Jonas Oreland
2005-10-11  7:35             ` Vladimir B. Savkin
2005-10-11  8:06               ` Andi Kleen
2005-10-11 16:27               ` Jonas Oreland
2005-10-25  7:35                 ` x86-64: Syncing dualcore cpus TSCs Jonas Oreland
2005-10-25  7:42                   ` Andi Kleen
2005-10-26  0:05                     ` David Lang

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=1127158937.3455.214.camel@cog.beaverton.ibm.com \
    --to=johnstul@us.ibm.com \
    --cc=ak@suse.de \
    --cc=akpm@osdl.org \
    --cc=discuss@x86-64.org \
    --cc=linux-kernel@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
all inboxes | Powered by JetHome®