Messages in this thread | | | Subject | Re: [RFC] Question about enable doorbell irq and halt_poll process | From | Heyi Guo <> | Date | Wed, 20 Mar 2019 22:31:36 +0800 |
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+cc Marc and Christoffer...
On 2019/3/19 21:25, Tangnianyao (ICT) wrote: > Hi, all > > Using gicv4, when guest is waiting for irq, it sends wfi and traps to kvm. > When vlpi is forwarded to PE after its_vpe_deschedule, before halt_poll in > kvm_vcpu_block, halt_poll may increase latency for this vlpi getting to guest. > In halt_poll process, it checks if there's pending irq for vcpu using pending_last. > However, doorbell is not enable at this moment and vlpi or doorbell can not set > pending_last true, to stop halt_poll. It will run until halt_poll time ends, if > there's no other physical irq coming in the meantime. And then vcpu is scheduled out. > This pending vlpi has to wait for vcpu getting schedule in next time. > > Should we enable doorbell before halt_poll process ? > > > . >
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