grow_halt_poll_ns() sets the halt_poll_ns value for a vCPU when growing - It has significant effect on how vCPU performs. On the standard case, higher value is better - we will spend more time in the polling busyloop, handle events & interrupts faster and result in better performance for the VM. But on outliers it puts us in a busy loop that does nothing. grow_halt_poll_ns() optimal algorithm changes between different workloads. The changes in this patch series fixes 2 weird behaviors and exposes hard-coded value which stands for the initial grow value in order to get a better fine-tunning control. See the individual patches for more details. Thanks, Nir --- Nir Weiner (3): KVM: grow_halt_poll_ns() should never shrink vCPU halt_poll_ns KVM: Expose the initial start value in grow_halt_poll_ns() as a module parameter KVM: Never start grow vCPU halt_poll_ns from value below halt_poll_ns_grow_start Documentation/virtual/kvm/halt-polling.txt | 37 +++++++++++-------- arch/powerpc/kvm/book3s_hv.c | 13 +++--- include/linux/kvm_host.h | 1 virt/kvm/kvm_main.c | 24 ++++++++---- 4 files changed, 47 insertions(+), 28 deletions(-)
