From: Andrew Morton <akpm@osdl.org>
To: Andi Kleen <ak@muc.de>
Cc: johnstul@us.ibm.com, smurf@smurf.noris.de,
linux-kernel@vger.kernel.org, torvalds@osdl.org, bunk@stusta.de,
lethal@linux-sh.org, hirofumi@mail.parknet.co.jp,
asit.k.mallick@intel.com
Subject: Re: REGRESSION: the new i386 timer code fails to sync CPUs
Date: Sun, 30 Jul 2006 13:55:18 -0700 [thread overview]
Message-ID: <20060730135518.f16c0399.akpm@osdl.org> (raw)
In-Reply-To: <20060730201005.GA85093@muc.de>
On 30 Jul 2006 22:10:05 +0200
Andi Kleen <ak@muc.de> wrote:
> > I guess Matthias didn't test this patch. Can we get some obviously-correct
> > fix in place for 2.6.18?
>
> So far we don't have any idea what the problem is on that system.
I believe we do know what the problem is: a) write_tsc() doesn't work, b)
the TSC's are unsynced (or have an offset), c) we removed a check which
would have caused pmtmr/rtc fallback.
> > It is a "CPU0: Intel(R) Xeon(TM) CPU 3.00GHz stepping 03".
>
> Was that on that system?
yes.
> I guess it could be checked for and TSC
> be forced off.
There's no need for that, I think. synchronize_tsc_bp() knows for-sure
that the synchronization failed, in a way which works on all CPUs.
So all we need to do is to set some flag in synchronize_tsc_bp() if `buggy'
is set, telling the clocksource code to give up on the TSC.
> It sounds like a real CPU bug however.
I was hoping the Intel guys could help out with that.
next prev parent reply other threads:[~2006-07-30 20:58 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-07-22 23:36 REGRESSION: the new i386 timer code fails to sync CPUs Matthias Urlichs
2006-07-23 0:36 ` Andrew Morton
2006-07-23 8:16 ` Matthias Urlichs
2006-07-23 11:46 ` Andrew Morton
2006-07-23 12:08 ` Matthias Urlichs
2006-07-23 12:37 ` Andrew Morton
2006-07-23 12:58 ` Matthias Urlichs
2006-07-24 15:52 ` Siddha, Suresh B
2006-07-24 15:58 ` john stultz
2006-07-24 17:17 ` Matthias Urlichs
2006-07-24 17:51 ` Andi Kleen
2006-07-24 20:54 ` john stultz
2006-07-30 9:03 ` Andrew Morton
2006-07-30 9:49 ` Matthias Urlichs
2006-07-30 20:10 ` Andi Kleen
2006-07-30 20:55 ` Andrew Morton [this message]
2006-07-30 21:13 ` Matthias Urlichs
2006-07-30 21:20 ` Arjan van de Ven
2006-07-30 21:55 ` Matthias Urlichs
2006-08-01 1:47 ` Siddha, Suresh B
2006-08-01 3:14 ` Matthias Urlichs
2006-07-30 21:57 ` Andi Kleen
2006-07-30 22:28 ` Matthias Urlichs
2006-07-31 14:24 ` Matthias Urlichs
2006-07-24 17:39 ` Andi Kleen
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