Re: [PATCH] scheduler: fix x86 regression in native_sched_clock

From: stefano . brivio
Date: Fri Dec 07 2007 - 06:25:14 EST


Quoting Nick Piggin <nickpiggin@xxxxxxxxxxxx>:

On Friday 07 December 2007 19:45, Ingo Molnar 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?

I guess so. Definitely, it didn't look like a printk issue. Drivers don't read logs, usually. But they got confused anyway (it seems that udelay's get scaled or fail or somesuch - I can't test it right now, will provide more feedback in a few hours).


--
Ciao
Stefano



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