Hi, I'm running a 3.4 kernel on both a host and a guest running in kvm. Within the guest cyclictest reported a 500usec outage.
On the host during that time I see the following trace: kvm-23696 4.N..2.. 507584568us : rcu_utilization: Start context switch kvm-23696 4.N..2.. 507584568us : rcu_utilization: End context switch kvm-23696 4dN..3.. 507584569us : sched_stat_runtime: comm=kvm pid=23696 runtime=2080 [ns] vruntime=87039278696560 [ns] kvm-23696 4d...3.. 507584569us : kvm_fpu: unload kvm-23696 4d...3.. 507584570us : sched_switch: prev_comm=kvm prev_pid=23696 prev_prio=120 prev_state=R+ ==> next_comm=ksoftirqd/4 next_pid=80 next_prio=98 ksoftirq-80 4....111 507584570us!: softirq_entry: vec=1 [action=TIMER] ksoftirq-80 4d...411 507585038us : sched_stat_runtime: comm=crond pid=29655 runtime=1153132 [ns] vruntime=2146330791534 [ns] ksoftirq-80 4d...411 507585038us : sched_stat_sleep: comm=rcu_preempt pid=12 delay=1458586 [ns] ksoftirq-80 4d...411 507585039us : sched_wakeup: comm=rcu_preempt pid=12 prio=120 success=1 target_cpu=000 ksoftirq-80 4....111 507585040us : softirq_exit: vec=1 [action=TIMER] ksoftirq-80 4....111 507585040us : softirq_entry: vec=9 [action=RCU] ksoftirq-80 4....111 507585040us : rcu_utilization: Start RCU core ksoftirq-80 4....111 507585041us : rcu_utilization: End RCU core ksoftirq-80 4....111 507585041us : softirq_exit: vec=9 [action=RCU] ksoftirq-80 4....2.. 507585041us : rcu_utilization: Start context switch ksoftirq-80 4....2.. 507585041us : rcu_utilization: End context switch ksoftirq-80 4....2.. 507585042us : rcu_utilization: Start context switch ksoftirq-80 4....2.. 507585042us : rcu_utilization: End context switch ksoftirq-80 4d...3.. 507585042us : sched_stat_wait: comm=kvm pid=23696 delay=474437 [ns] ksoftirq-80 4d...3.. 507585043us+: sched_switch: prev_comm=ksoftirqd/4 prev_pid=80 prev_prio=98 prev_state=S ==> next_comm=kvm next_pid=23696 next_prio=120 kvm-23696 4d...2.. 507585044us : rcu_utilization: Start context switch kvm-23696 4d...2.. 507585044us : rcu_utilization: End context switch kvm-23696 4d...2.. 507585044us : kvm_entry: vcpu 1 kvm-23696 4d...2.. 507585045us : kvm_exit: vcpu 1 reason MSR_WRITE rip 0xffffffff81026e08 info 0 0 I'm trying to figure out what would cause that jump between the first two ksoftirqd logs. Some stuff in /proc/cmdline that might be relevent (it's a bit of a mishmash, I know): intel_iommu=off isolcpus=1-15 rcu_nocbs=1-15 irqaffinity=0 intel_idle.max_cstate=0 processor.max_cstate=1 idle=poll In the BIOS we've disabled speedstep, CPU C states, and NMI on error. Is there a different tracer that would give more insight? The irqs-off or preemption-off tracers perhaps? Please CC me as I'm not subscribed to the list. Thanks, Chris Friesen -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/