On Tue, Jun 28, 2016 at 10:43:07AM -0400, Pan Xinhui wrote:
> change fomr v1:
>       a simplier definition of default vcpu_is_preempted
>       skip mahcine type check on ppc, and add config. remove dedicated macro.
>       add one patch to drop overload of rwsem_spin_on_owner and 
> mutex_spin_on_owner. 
>       add more comments
>       thanks boqun and Peter's suggestion.
> 
> This patch set aims to fix lock holder preemption issues.
> 
> test-case:
> perf record -a perf bench sched messaging -g 400 -p && perf report
> 
> 18.09%  sched-messaging  [kernel.vmlinux]  [k] osq_lock
> 12.28%  sched-messaging  [kernel.vmlinux]  [k] rwsem_spin_on_owner
>  5.27%  sched-messaging  [kernel.vmlinux]  [k] mutex_unlock
>  3.89%  sched-messaging  [kernel.vmlinux]  [k] wait_consider_task
>  3.64%  sched-messaging  [kernel.vmlinux]  [k] _raw_write_lock_irq
>  3.41%  sched-messaging  [kernel.vmlinux]  [k] mutex_spin_on_owner.is
>  2.49%  sched-messaging  [kernel.vmlinux]  [k] system_call
> 
> We introduce interface bool vcpu_is_preempted(int cpu) and use it in some spin
> loops of osq_lock, rwsem_spin_on_owner and mutex_spin_on_owner.
> These spin_on_onwer variant also cause rcu stall before we apply this patch 
> set
> 

Paolo, could you help out with an (x86) KVM interface for this?

Waiman, could you see if you can utilize this to get rid of the
SPIN_THRESHOLD in qspinlock_paravirt?
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev

Reply via email to