Messages in this thread | | | Date | Fri, 10 Dec 2010 16:50:21 +0000 | From | Russell King - ARM Linux <> | Subject | Re: [BUG] 2.6.37-rc3 massive interactivity regression on ARM |
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On Fri, Dec 10, 2010 at 02:47:46PM +0100, Peter Zijlstra wrote: > > Full patch.. > > --- > Subject: sched: Fix the irqtime code to deal with u64 wraps > From: Peter Zijlstra <a.p.zijlstra@chello.nl> > Date: Thu Dec 09 14:15:34 CET 2010 > > ARM systems have a 32bit sched_clock() [ which needs to be fixed ], > but this exposed a bug in the irq_time code as well, it doesn't deal > with wraps at all. > > Fix the irq_time code to deal with u64 wraps by re-writing the code to > only use delta increments, which avoids the whole issue. > > Furthermore, solve the problem of 32bit arches reading partial updates > of the u64 time values. > > Cc: Venkatesh Pallipadi <venki@google.com> > Reported-by: Russell King - ARM Linux <linux@arm.linux.org.uk>
I think credit should go to Mikael Pettersson, who identified the interactivity regression and problematical commit. I only pointed out the dubious nature of the code.
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