On 04/06/2016 02:42, Yunhong Jiang wrote: > It adds a little bit latency for each VM-entry because we need setup the > preemption timer each time. Really it doesn't according to your tests: > 1. enable_hv_timer=Y. > > 000004 002174 > 000005 042961 > 000006 479383 > 000007 071123 > 000008 003720 > > 2. enable_hv_timer=N. > > # Histogram > ...... > 000005 000042 > 000006 000772 > 000007 008262 > 000008 200759 > 000009 381126 > 000010 008056 So perhaps you can replace that paragraph with "The benefits offset the small extra work to do on each VM-entry to setup the preemption timer". I'll play with this patch and kvm-unit-tests in the next few days. David, it would be great if you could also try this on your message-passing benchmarks (e.g. TCP_RR). On one hand they are heavy on vmexits, on the other hand they also have many expensive TSC deadline WRMSRs. I have requested a few small changes, but I am very happy with the logic and the vmentry cost. Thanks, Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
