v1 -> v2: * change kvm_vcpu_block to read halt_poll_ns from the vcpu instead of the module parameter * use the shrink/grow matrix which is suggested by David * set halt_poll_ns_max to 2ms
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. There are two new kernel parameters for changing the halt_poll_ns: halt_poll_ns_grow and 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. The shrink/grow matrix is suggested by David: if (poll successfully for interrupt): stay the same else if (length of kvm_vcpu_block is longer than halt_poll_ns_max): shrink else if (length of kvm_vcpu_block is less than halt_poll_ns_max): grow halt_poll_ns_shrink/ | halt_poll_ns_grow | grow halt_poll_ns | shrink halt_poll_ns ---------------------+----------------------+------------------- < 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 Wanpeng Li (3): KVM: make halt_poll_ns per-VCPU KVM: dynamic 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 | 78 ++++++++++++++++++++++++++++++++++++++++++++-- 3 files changed, 106 insertions(+), 3 deletions(-) -- 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
