From: Dave Jones <davej@redhat.com>
To: Lee Revell <rlrevell@joe-job.com>
Cc: thockin@hockin.org, Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@elte.hu>, john stultz <johnstul@us.ibm.com>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RT] read_tsc: ACK! TSC went backward! Unsynced TSCs?
Date: Mon, 28 Nov 2005 13:30:23 -0500 [thread overview]
Message-ID: <20051128183023.GC30899@redhat.com> (raw)
In-Reply-To: <1133199568.7416.31.camel@mindpipe>
On Mon, Nov 28, 2005 at 12:39:28PM -0500, Lee Revell wrote:
> On Mon, 2005-11-28 at 09:30 -0800, thockin@hockin.org wrote:
> > The kernel's use of TSC is wholly incorrect. TSCs can ramp up and
> > down and *do* vary between nodes as well as between cores within a
> > node. You really can not compare TSCs between cpu cores at all, as is
> > (and the kernel assumes 1 global TSC in at least a few places).
>
> That's one way to look at it; another is that the AMD dual cores have a
> broken TSC implementation. The kernel's use of the TSC was never a
> problem in the past...
Not true. Speedstep, or anything else that uses SMI to disappear
into magick bios code for long periods of time also have exactly
the same issue.
This is not a new problem.
Dave
next prev parent reply other threads:[~2005-11-28 18:31 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-11-28 12:05 [RT] read_tsc: ACK! TSC went backward! Unsynced TSCs? Steven Rostedt
2005-11-28 12:30 ` Jonas Oreland
2005-11-28 12:59 ` Steven Rostedt
2005-11-28 14:21 ` Ingo Molnar
2005-11-28 15:38 ` Lee Revell
2005-11-28 17:30 ` thockin
2005-11-28 17:39 ` Lee Revell
2005-11-28 18:30 ` Dave Jones [this message]
2005-11-28 18:35 ` thockin
2005-11-29 14:06 ` Andi Kleen
2005-11-29 16:52 ` thockin
2005-11-29 16:48 ` Andi Kleen
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=20051128183023.GC30899@redhat.com \
--to=davej@redhat.com \
--cc=johnstul@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=rlrevell@joe-job.com \
--cc=rostedt@goodmis.org \
--cc=thockin@hockin.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