On Mon, 10 Jun 2019 at 22:34, Radim Krčmář <rkrcmar@xxxxxxxxxx> wrote: > > 2019-05-30 09:05+0800, Wanpeng Li: > > The idea is from Xen, when sending a call-function IPI-many to vCPUs, > > yield if any of the IPI target vCPUs was preempted. 17% performance > > increasement of ebizzy benchmark can be observed in an over-subscribe > > environment. (w/ kvm-pv-tlb disabled, testing TLB flush call-function > > IPI-many since call-function is not easy to be trigged by userspace > > workload). > > Have you checked if we could gain performance by having the yield as an > extension to our PV IPI call? It will extend irq disabled time in __send_ipi_mask(). In addition, sched yield can be used to optimize other synchronization primitives in guest I think. Regards, Wanpeng Li
