L2 hackbench 86 sec with 1/100 irq

root@kvm-guest:~# ./hackbench 2
Running with 2*40 (== 80) tasks.
[  245.429039] kvm [1539]: fault_ipa: f9a18000
[  245.429806] kvm [1539]: pfn: 3a2018
[  245.435039] kvm [1539]: fault_ipa: f8e00000
[  245.435749] kvm [1539]: pfn: f4000
[  245.493865] kvm [1539]: fault_ipa: f8800000
[  245.494593] kvm [1539]: pfn: 3a1600
[  254.077918] INFO: rcu_preempt detected stalls on CPUs/tasks:
[  254.137813] 	Tasks blocked on level-0 rcu_node (CPUs 0-0): P1586
[  254.201735] 	(detected by 0, t=5253 jiffies, g=665, c=664, q=436)
[  254.266325] Call trace:
[  254.298112] Call trace:
[  290.855059] INFO: rcu_preempt detected stalls on CPUs/tasks:
[  290.914881] 	Tasks blocked on level-0 rcu_node (CPUs 0-0): P1546
[  290.980629] 	(detected by 0, t=5262 jiffies, g=667, c=666, q=608)
[  291.045409] Call trace:
[  291.077375] Call trace:
Time: 86.473
root@kvm-guest:~#