lkml.org 
[lkml]   [2012]   [Aug]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6
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



\
 
 \ /
  Last update: 2012-08-06 21:01    [W:0.097 / U:0.980 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site