Messages in this thread | | | Date | Tue, 14 May 2013 02:57:46 +0200 | From | Frederic Weisbecker <> | Subject | Re: dynticks: CONFIG_VIRT_CPU_ACCOUNTING + CONFIG_CONTEXT_TRACKING breaks accounting on core2 CPUs only |
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On Sun, May 12, 2013 at 10:17:49AM +0200, Mike Galbraith wrote: > Greetings, > > Turning on new NO_HZ feature on my Q6600 box in master, I see that tasks > accrue zero utime/stime. However, the same exact kernel on E5620 box > works fine, so it would appear there's a CPU dependency somewhere.
Ah indeed, I just managed to reproduce the same issue.
> > Is core2 expected to go dysfunctional with context tracking enabled? > CONFIG_VIRT_CPU_ACCOUNTING alone works fine in 3.9-stable, turn on > CONFIG_CONTEXT_TRACKING_FORCE, and CPU accounting stops working on core2 > boxen only, same exact kernel continues to work just fine on E5620 > (Westmere) box.
There was no known issue with core2. The box where I'm seeing the it is a Phenom quad core that had NR_CPUS=2. May be the issue is more likely to happen with this low number. I don't know.
I'm investigating further.
Thanks.
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