Messages in this thread | | | Date | Mon, 06 Aug 2012 11:20:31 -0700 | From | John Stultz <> | Subject | Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6 |
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On 08/06/2012 10:21 AM, John Stultz wrote: > On 08/05/2012 09:55 AM, Sasha Levin wrote: >> On 07/30/2012 03:17 PM, Avi Kivity wrote: >>> Possible causes: >>> - the APIC calibration in the guest failed, so it is programming too >>> low values into the timer >>> - it actually needs 1 us wakeups and then can't keep up (esp. as kvm >>> interrupt injection is slowing it down) >>> >>> You can try to find out by changing >>> arch/x86/kvm/lapic.c:start_lapic_timer() to impose a minimum wakeup of >>> (say) 20 microseconds which will let the guest live long enough for you >>> to ftrace it and see what kind of timers it is programming. >> I've kept trying to narrow it down, and found out It's triggerable >> using adjtimex(). Sorry, one more question: Could you provide details on how is it trigger-able using adjtimex?
thanks -john
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