Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-07 Thread Michael Wang
On 08/07/2012 06:24 PM, Sasha Levin wrote: > On 08/07/2012 07:40 AM, John Stultz wrote: >> On 08/06/2012 11:28 AM, Sasha Levin wrote: >>> On 08/06/2012 08:20 PM, John Stultz wrote: On 08/06/2012 10:21 AM, John Stultz wrote: > On 08/05/2012 09:55 AM, Sasha Levin wrote: >> On 07/30/2012

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-07 Thread Sasha Levin
On 08/07/2012 07:40 AM, John Stultz wrote: > On 08/06/2012 11:28 AM, Sasha Levin wrote: >> On 08/06/2012 08:20 PM, John Stultz wrote: >>> 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

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread John Stultz
On 08/06/2012 11:28 AM, Sasha Levin wrote: On 08/06/2012 08:20 PM, John Stultz wrote: 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 progra

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread Michael Wang
On 08/07/2012 04:35 AM, Sasha Levin wrote: > On 08/06/2012 10:31 PM, John Stultz wrote: >> On 08/06/2012 11:28 AM, Sasha Levin wrote: >>> On 08/06/2012 08:20 PM, John Stultz wrote: On 08/06/2012 10:21 AM, John Stultz wrote: > On 08/05/2012 09:55 AM, Sasha Levin wrote: >> On 07/30/2012

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread Sasha Levin
On 08/06/2012 10:31 PM, John Stultz wrote: > On 08/06/2012 11:28 AM, Sasha Levin wrote: >> On 08/06/2012 08:20 PM, John Stultz wrote: >>> 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

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread John Stultz
On 08/06/2012 11:28 AM, Sasha Levin wrote: On 08/06/2012 08:20 PM, John Stultz wrote: 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 progra

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread Sasha Levin
On 08/06/2012 07:21 PM, 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 a

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread Sasha Levin
On 08/06/2012 08:20 PM, John Stultz wrote: > 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

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread John Stultz
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 kee

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread John Stultz
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 kee

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-06 Thread John Stultz
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 slo

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-08-05 Thread Sasha Levin
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

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-30 Thread Avi Kivity
On 07/30/2012 03:43 PM, Sasha Levin wrote: > >> Then work backwards to see the last place it is >> programmed (APIC_TMICT/APIC_TDCR). > > This looks like what you're looking for: > > kvm_apic: apic_write APIC_TMICT = 0x3e >> >> What about APIC_TMICT? Might be configure

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-30 Thread Sasha Levin
On 07/30/2012 11:33 AM, Avi Kivity wrote: > On 07/30/2012 12:13 PM, Sasha Levin wrote: >> >> Yup, looks like it. kvm_stats is something like this: >> >> kvm_entry142104033 939393 >> kvm_exit 142104004 939390 >>>

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-30 Thread Avi Kivity
On 07/30/2012 12:13 PM, Sasha Levin wrote: > > Yup, looks like it. kvm_stats is something like this: > > kvm_entry142104033 939393 > kvm_exit 142104004 939390 > kvm_apic 847

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-30 Thread Sasha Levin
On 07/30/2012 07:36 AM, Avi Kivity wrote: > On 07/30/2012 12:05 AM, Sasha Levin wrote: >> On 07/29/2012 02:48 PM, Avi Kivity wrote: >>> On 07/27/2012 02:27 PM, Sasha Levin wrote: On 07/26/2012 01:42 PM, Avi Kivity wrote: > On 07/24/2012 08:10 PM, Sasha Levin wrote: >> [ 215.026612] NM

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-29 Thread Avi Kivity
On 07/30/2012 12:05 AM, Sasha Levin wrote: > On 07/29/2012 02:48 PM, Avi Kivity wrote: > > On 07/27/2012 02:27 PM, Sasha Levin wrote: > >> On 07/26/2012 01:42 PM, Avi Kivity wrote: > >>> On 07/24/2012 08:10 PM, Sasha Levin wrote: > [ 215.026612] NMI backtrace for cpu 1 > [ 215.026612] C

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-29 Thread Sasha Levin
On 07/29/2012 02:48 PM, Avi Kivity wrote: > On 07/27/2012 02:27 PM, Sasha Levin wrote: >> On 07/26/2012 01:42 PM, Avi Kivity wrote: >>> On 07/24/2012 08:10 PM, Sasha Levin wrote: [ 215.026612] NMI backtrace for cpu 1 [ 215.026612] CPU 1 [ 215.026612] Pid: 2395, comm: pageattr-test

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-29 Thread Avi Kivity
On 07/27/2012 02:27 PM, Sasha Levin wrote: > On 07/26/2012 01:42 PM, Avi Kivity wrote: >> On 07/24/2012 08:10 PM, Sasha Levin wrote: >>> [ 215.026612] NMI backtrace for cpu 1 >>> [ 215.026612] CPU 1 >>> [ 215.026612] Pid: 2395, comm: pageattr-test Tainted: GW >>> 3.5.0-sasha-01644-g8

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-27 Thread Sasha Levin
On 07/26/2012 01:42 PM, Avi Kivity wrote: > On 07/24/2012 08:10 PM, Sasha Levin wrote: >> [ 215.026612] NMI backtrace for cpu 1 >> [ 215.026612] CPU 1 >> [ 215.026612] Pid: 2395, comm: pageattr-test Tainted: GW >> 3.5.0-sasha-01644-g824681b #267 >> [ 215.026612] RIP: 0010:[] [] >>

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-26 Thread Avi Kivity
On 07/24/2012 08:10 PM, Sasha Levin wrote: > [ 215.026612] NMI backtrace for cpu 1 > [ 215.026612] CPU 1 > [ 215.026612] Pid: 2395, comm: pageattr-test Tainted: GW > 3.5.0-sasha-01644-g824681b #267 > [ 215.026612] RIP: 0010:[] [] > native_write_msr_safe+0xa/0x10 > [ 215.026612] R

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-25 Thread Michael Wang
On 07/26/2012 05:16 AM, Sasha Levin wrote: > On 07/25/2012 10:36 AM, Michael Wang wrote: >> On 07/25/2012 01:10 AM, Sasha Levin wrote: >>> Hi all, >>> >>> I was fuzzing with trinity inside a KVM tools guest, on the current 3.6, >>> and stumbled on the following: >> >> Hi, Sasha >> >> I'm currently

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-25 Thread Michael Wang
On 07/25/2012 01:10 AM, Sasha Levin wrote: > Hi all, > > I was fuzzing with trinity inside a KVM tools guest, on the current 3.6, and > stumbled on the following: And is this a host dmesg or from the guest? Could you please provide more details about your testing environment? Thanks, Michael Wa

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-25 Thread Michael Wang
On 07/25/2012 01:10 AM, Sasha Levin wrote: > Hi all, > > I was fuzzing with trinity inside a KVM tools guest, on the current 3.6, and > stumbled on the following: Hi, Sasha I'm currently trying to reproduce this issue on my machine but keep failing, it's really make me think the issue has been

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-24 Thread Sasha Levin
On 07/24/2012 07:40 PM, Paul E. McKenney wrote: > The interrupt flag is zero, so interrupts are disabled. So my question > to you is "Why did do_pageattr_test() or one of the functions it called > disable interrupts for more than one hundred thousand jiffies?" > > I can't see where it is disablin

Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-24 Thread Paul E. McKenney
On Tue, Jul 24, 2012 at 07:10:49PM +0200, Sasha Levin wrote: > Hi all, > > I was fuzzing with trinity inside a KVM tools guest, on the current 3.6, and > stumbled on the following: > > (Note that it also happens on -next). > > [ 215.034674] INFO: rcu_preempt detected stalls on CPUs/tasks: > [

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6

2012-07-24 Thread Sasha Levin
Hi all, I was fuzzing with trinity inside a KVM tools guest, on the current 3.6, and stumbled on the following: (Note that it also happens on -next). [ 215.034674] INFO: rcu_preempt detected stalls on CPUs/tasks: [ 215.035641] 1: (0 ticks this GP) idle=3f5/141/0 drain=0 . timer=