There is a downside of halt_poll_ns since poll is still happen for idle VCPU which can waste cpu usage. This patchset add the ability to adjust halt_poll_ns dynamically, grows halt_poll_ns if an interrupt arrives and shrinks halt_poll_ns when idle VCPU is detected.
There are two new kernel parameters for changing the halt_poll_ns: halt_poll_ns_grow and halt_poll_ns_shrink. halt_poll_ns_grow affects halt_poll_ns when an interrupt arrives and halt_poll_ns_shrink does it when idle VCPU is detected. halt_poll_ns_shrink/ | halt_poll_ns_grow | interrupt arrives | idle VCPU is detected ---------------------+----------------------+------------------- < 1 | = halt_poll_ns | = 0 < halt_poll_ns | *= halt_poll_ns_grow | /= halt_poll_ns_shrink otherwise | += halt_poll_ns_grow | -= halt_poll_ns_shrink A third new parameter, halt_poll_ns_max, controls the maximal halt_poll_ns; it is internally rounded down to a closest multiple of halt_poll_ns_grow. Wanpeng Li (3): KVM: make halt_poll_ns per-VCPU KVM: dynamise halt_poll_ns adjustment KVM: trace kvm_halt_poll_ns grow/shrink include/linux/kvm_host.h | 1 + include/trace/events/kvm.h | 30 ++++++++++++++++ virt/kvm/kvm_main.c | 90 +++++++++++++++++++++++++++++++++++++++++++++- 3 files changed, 120 insertions(+), 1 deletion(-) -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
