From: Andrew Morton <akpm@osdl.org>
To: Andi Kleen <ak@suse.de>
Cc: raybry@mpdtxmail.amd.com, dan@debian.org, johnstul@us.ibm.com,
ak@suse.de, linux-kernel@vger.kernel.org, discuss@x86-64.org
Subject: Re: [discuss] Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs
Date: Wed, 21 Sep 2005 13:17:13 -0700 [thread overview]
Message-ID: <20050921131713.06787aa1.akpm@osdl.org> (raw)
In-Reply-To: <20050921150404.GD12810@verdi.suse.de>
Andi Kleen <ak@suse.de> wrote:
>
> On Wed, Sep 21, 2005 at 10:15:08AM -0500, Ray Bryant wrote:
> > On Tuesday 20 September 2005 23:03, Daniel Jacobowitz wrote:
> >
> > >
> > > FYI, at least I have reproduced this without powernow loaded.
> >
> > There are cases that we are aware of where the TSC will count slower while the
> > processor is halted. This can make TSC's get out of sync on dual cores.
You mean a single `hlt' instruction? I guess that rules out resyncing them.
> Ok thanks for the confirmation. I guess John's patch is ok then.
> Drawback is much slower to extremly slow gettimeofday (depending
> if the chipset/BIOS has usable HPET, most seem not to)
That's a really big drawback. Will this affect many CPU types?
If the user was prepared to use `idle=poll' then they could get their fast
gettimeofday() back, perhaps.
next prev parent reply other threads:[~2005-09-21 20:19 UTC|newest]
Thread overview: 28+ 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
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 [this message]
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
2005-09-20 19:13 [discuss] Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs Langsdorf, Mark
2005-09-20 19:24 ` Scott Lampert
2005-09-20 19:30 ` john stultz
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