From: Andi Kleen <ak@suse.de>
To: thockin@hockin.org
Cc: Luca Tettamanti <kronos.it@gmail.com>,
Lee Revell <rlrevell@joe-job.com>,
linux-kernel@vger.kernel.org, john stultz <johnstul@us.ibm.com>
Subject: Re: AMD X2 unsynced TSC fix?
Date: Fri, 27 Oct 2006 18:04:52 -0700 [thread overview]
Message-ID: <200610271804.52727.ak@suse.de> (raw)
In-Reply-To: <20061027230458.GA27976@hockin.org>
> Wrong, too. We have a patch that will be coming SOON (trust me, I am
> pushing hard for the author to publish it). With this patch applied you
> should never see the TSC go backwards. Period. It should be monotonic
> (to userspace, kernel rdtsc calls can still be wrong). CPUs should stay
> very nearly in sync (again, to userspace). The Thoverhead of this patch is
> pretty minimal and costs nothing unless you actually read the TSC.
There is another patch in the pipeline to make gettimeofday use
RDTSC in more cases by keeping the offsets per CPU
(this has nothing to do with syncing TSCs which is not possible
in the general case on several platforms)
I don't think it makes too much sense to hack on pure RDTSC when
gtod is fast enough -- RDTSC will be always icky and hard to use.
-Andi
next prev parent reply other threads:[~2006-10-28 1:05 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-10-27 17:15 AMD X2 unsynced TSC fix? Lee Revell
2006-10-27 20:18 ` Luca Tettamanti
2006-10-27 23:04 ` thockin
2006-10-28 0:00 ` Luca Tettamanti
2006-10-28 0:17 ` Lee Revell
2006-10-28 2:46 ` thockin
2006-10-28 3:59 ` Andi Kleen
2006-10-28 6:32 ` thockin
2006-10-28 9:14 ` Vojtech Pavlik
2006-10-28 18:22 ` Lee Revell
2006-10-28 19:57 ` Vojtech Pavlik
2006-10-28 22:54 ` thockin
2006-10-28 1:04 ` Andi Kleen [this message]
2006-10-28 3:28 ` Lee Revell
2006-10-28 5:28 ` Willy Tarreau
2006-10-28 18:08 ` Lee Revell
2006-10-28 19:14 ` thockin
2006-10-30 17:22 ` Langsdorf, Mark
2006-10-28 18:37 ` Andi Kleen
2006-10-28 19:15 ` Willy Tarreau
2006-10-28 19:18 ` thockin
2006-10-28 19:32 ` Willy Tarreau
2006-10-28 19:42 ` thockin
2006-10-28 20:16 ` Willy Tarreau
2006-10-28 19:33 ` Andi Kleen
2006-10-28 20:04 ` Willy Tarreau
2006-10-28 20:11 ` Andi Kleen
2006-10-28 20:36 ` Willy Tarreau
2006-10-29 1:28 ` Lee Revell
2006-10-28 21:00 ` Lee Revell
2006-10-31 11:12 ` Pádraig Brady
2006-10-31 15:31 ` Willy Tarreau
2006-10-30 20:30 ` Christoph Lameter
2006-10-27 20:35 ` Andi Kleen
2006-10-27 20:41 ` Lee Revell
2006-10-27 21:48 ` Chris Friesen
2006-10-27 22:08 ` Lee Revell
2006-10-28 3:58 ` Sergio Monteiro Basto
2006-10-28 4:06 ` Andi Kleen
2006-10-28 4:22 ` Sergio Monteiro Basto
2006-10-30 3:10 ` Sergio Monteiro Basto
2006-10-30 15:23 ` Andi Kleen
[not found] ` <1162253008.2999.9.camel@localhost.portugal>
2006-10-31 0:14 ` Lee Revell
2006-10-31 0:25 ` john stultz
2006-10-31 2:41 ` Siddha, Suresh B
2006-10-31 15:05 ` Sergio Monteiro Basto
2006-11-01 1:46 ` Sergio Monteiro Basto
2006-11-01 2:44 ` Siddha, Suresh B
2006-11-08 0:22 ` Sergio Monteiro Basto
2006-11-08 19:53 ` Thomas Gleixner
2006-11-09 0:39 ` Sergio Monteiro Basto
2006-11-09 1:13 ` john stultz
2006-11-09 1:27 ` Sergio Monteiro Basto
2006-11-15 1:51 ` Sergio Monteiro Basto
[not found] ` <20061115193514.41C01102C011@mail.goron.de>
2006-11-16 1:38 ` Sergio Monteiro Basto
2006-11-16 1:45 ` Sergio Monteiro Basto
2006-10-28 6:35 ` thockin
2006-10-28 6:46 ` Andrew Morton
2006-10-28 6:49 ` thockin
2006-10-28 7:13 ` Andrew Morton
2006-10-28 7:25 ` thockin
2006-10-28 9:46 ` Andi Kleen
2006-10-28 9:45 ` Andi Kleen
2006-10-28 9:48 ` Andi Kleen
2006-10-27 21:58 ` Friedrich Göpel
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