Date: Fri, 7 Dec 2007 12:17:20 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Nick Piggin <nickpiggin@yahoo.com.au>
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
Message-ID: <20071207111720.GA10543@elte.hu>
References: <20071207021952.6f0ac922@morte> <20071207084559.GA11162@elte.hu> <200712072213.06530.nickpiggin@yahoo.com.au>
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* 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().

	Ingo
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