From: Peter Zijlstra <peterz@infradead.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Alex Shi <alex.shi@intel.com>,
hpa@linux.intel.com, tim.c.chen@linux.intel.com,
linux-kernel@vger.kernel.org, andi.kleen@intel.com,
mingo@elte.hu
Subject: Re: [URGENT rfc patch 0/3] tsc clocksource bug fix
Date: Sat, 6 Jul 2013 12:50:10 +0200 [thread overview]
Message-ID: <20130706105010.GV18898@dyad.programming.kicks-ass.net> (raw)
In-Reply-To: <alpine.DEB.2.02.1307052345330.32106@ionos.tec.linutronix.de>
On Fri, Jul 05, 2013 at 11:50:05PM +0200, Thomas Gleixner wrote:
> On Fri, 5 Jul 2013, Peter Zijlstra wrote:
> > On Fri, Jul 05, 2013 at 05:24:09PM +0200, Thomas Gleixner wrote:
> > > See arch/x86/kernel/tsc.c
> > >
> > > We disable the watchdog for the TSC when tsc_clocksource_reliable is
> > > set.
> > >
> > > tsc_clocksource_reliable is set when:
> > >
> > > - you add tsc=reliable to the kernel command line
> >
> > Ah, I didn't know about that one, useful.
> >
> > > - boot_cpu_has(X86_FEATURE_TSC_RELIABLE)
> > >
> > > X86_FEATURE_TSC_RELIABLE is a software flag, set by vmware and
> > > moorsetown. So all other machines keep the watchdog enabled.
> >
> > Right.. I knew it was enabled on my machines even though they normally
> > have usable TSC.
>
> Yeah, but our well justified paranoia still prevents us from trusting
> these CPU flags. Maybe some day BIOS is going to be replaced by
> something useful. You know: Hope springs eternal....
Oh quite agreed. Its just that at several times I've wanted to disable the
thing. Now I know you can do using the kernel cmdline. Previously I had to
wreck code -- not that much harder really :-)
next prev parent reply other threads:[~2013-07-06 10:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-04 5:34 [URGENT rfc patch 0/3] tsc clocksource bug fix Alex Shi
2013-07-04 5:34 ` [PATCH 1/3] clocksource: clean up clocksource_select Alex Shi
2013-07-04 9:57 ` Thomas Gleixner
2013-07-04 10:21 ` Alex Shi
2013-07-04 10:27 ` Thomas Gleixner
2013-07-05 1:22 ` Alex Shi
2013-07-04 5:34 ` [PATCH 2/3] clockesource: set override clocksource Alex Shi
2013-07-04 10:23 ` Thomas Gleixner
2013-07-04 5:34 ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-04 10:55 ` Thomas Gleixner
2013-07-04 13:04 ` Thomas Gleixner
2013-07-04 20:46 ` [PATCH] clocksource: Reselect clocksource when watchdog validated Thomas Gleixner
2013-07-05 1:38 ` Alex Shi
2013-07-05 9:13 ` [tip:timers/core] clocksource: Reselect clocksource when watchdog validated high-res capability tip-bot for Thomas Gleixner
2013-07-05 2:48 ` [PATCH 3/3] clocksource: fix can not set tsc as clocksource bug Alex Shi
2013-07-05 5:41 ` Thomas Gleixner
2013-07-05 6:44 ` Alex Shi
2013-07-04 7:58 ` [URGENT rfc patch 0/3] tsc clocksource bug fix Peter Zijlstra
2013-07-04 8:13 ` Alex Shi
2013-07-05 14:23 ` Frederic Weisbecker
2013-07-05 14:38 ` Peter Zijlstra
2013-07-05 15:24 ` Thomas Gleixner
2013-07-05 21:22 ` Peter Zijlstra
2013-07-05 21:50 ` Thomas Gleixner
2013-07-05 21:58 ` Borislav Petkov
2013-07-05 22:17 ` Thomas Gleixner
2013-07-06 8:37 ` Borislav Petkov
2013-07-06 10:50 ` Peter Zijlstra [this message]
2013-07-04 11:00 ` Thomas Gleixner
2013-07-04 18:11 ` Davidlohr Bueso
2013-07-04 20:27 ` Thomas Gleixner
2013-07-05 1:12 ` Alex Shi
2013-07-05 5:58 ` Thomas Gleixner
2013-07-05 6:28 ` Alex Shi
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