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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Ingo Molnar <mingo@elte.hu>
Cc: Stefano Brivio <stefano.brivio@polimi.it>,
	Robert Love <rml@tech9.net>,
	linux-kernel@vger.kernel.org, Dave Jones <davej@redhat.com>,
	"Rafael J. Wysocki" <rjw@sisk.pl>, Michael Buesch <mb@bu3sch.de>,
	Thomas Gleixner <tglx@linutronix.de>,
	Andrew Morton <akpm@linux-foundation.org>,
	Len Brown <lenb@kernel.org>
Subject: Re: [PATCH] scheduler: fix x86 regression in native_sched_clock
Date: Sat, 8 Dec 2007 03:48:52 +1100	[thread overview]
Message-ID: <200712080348.53117.nickpiggin@yahoo.com.au> (raw)
In-Reply-To: <20071207111720.GA10543@elte.hu>

On Friday 07 December 2007 22:17, Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> > > ah, printk_clock() still uses sched_clock(), not jiffies. So it's
> > > not the jiffies counter that goes back and forth, it's sched_clock()
> > > - so this is a printk timestamps anomaly, not related to jiffies. I
> > > thought we have fixed this bug in the printk code already:
> > > sched_clock() is a 'raw' interface that should not be used directly
> > > - the proper interface is cpu_clock(cpu).
> >
> > It's a single CPU box, so sched_clock() jumping would still be
> > problematic, no?
>
> sched_clock() is an internal API - the non-jumping API to be used by
> printk is cpu_clock().

You know why sched_clock jumps when the TSC frequency changes, right?


  reply	other threads:[~2007-12-07 16:50 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-12-07  1:19 [PATCH] scheduler: fix x86 regression in native_sched_clock Stefano Brivio
2007-12-07  5:29 ` Nick Piggin
2007-12-07  5:51 ` Thomas Gleixner
2007-12-07  7:18   ` Guillaume Chazarain
2007-12-07  8:02     ` Guillaume Chazarain
2007-12-07  8:51       ` Ingo Molnar
2007-12-07  9:29         ` Guillaume Chazarain
2007-12-07  9:59           ` Ingo Molnar
2007-12-07 13:55       ` [patch] x86: scale cyc_2_nsec according to CPU frequency Ingo Molnar
2007-12-07 14:27         ` Guillaume Chazarain
2007-12-07 14:52           ` Ingo Molnar
2007-12-08 15:57             ` Arjan van de Ven
2007-12-08 19:16               ` Ingo Molnar
2007-12-08 20:18                 ` Arjan van de Ven
2007-12-07 10:37   ` [PATCH] scheduler: fix x86 regression in native_sched_clock Andi Kleen
2007-12-07  8:45 ` Ingo Molnar
2007-12-07 10:32   ` Andrew Morton
2007-12-07 10:40     ` Ingo Molnar
2007-12-07 11:07       ` Ingo Molnar
2007-12-07 11:09       ` Andrew Morton
2007-12-07 11:12         ` Ingo Molnar
2007-12-07 11:13   ` Nick Piggin
2007-12-07 11:17     ` Ingo Molnar
2007-12-07 16:48       ` Nick Piggin [this message]
2007-12-08  0:50         ` Nick Piggin
2007-12-08  0:57           ` Nick Piggin
2007-12-08  8:52             ` Ingo Molnar
2007-12-08 23:37               ` Guillaume Chazarain
2007-12-12  4:42               ` Nick Piggin
2007-12-12 10:44                 ` Ingo Molnar
2007-12-07 11:18     ` Guillaume Chazarain
2007-12-07 11:57       ` Guillaume Chazarain
2007-12-07 11:23     ` stefano.brivio
2007-12-07 12:11       ` Ingo Molnar
2007-12-07 12:25       ` Ingo Molnar
2007-12-07 12:35         ` Ingo Molnar
2007-12-07 12:40           ` Ingo Molnar
2007-12-07 14:54             ` Ingo Molnar
2007-12-07 16:46               ` Guillaume Chazarain
2007-12-07 17:57                 ` Ingo Molnar
2007-12-08 15:06                   ` Mark Lord
2007-12-08 15:13                     ` Ingo Molnar
2007-12-08 15:27                       ` Michael Buesch
2007-12-08 15:33                         ` Ingo Molnar
2007-12-08 15:36                           ` Michael Buesch
2007-12-08 15:41                             ` Ingo Molnar
2007-12-07 11:24     ` Ingo Molnar

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