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? _______________________________________________ Virtualization mailing list Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linuxfoundation.org/mailman/listinfo/virtualization
