On 02/03/20 18:11, Wei Huang wrote: >>> I personally don't suggest enable AVIC by default. There are cases of >>> slow AVIC doorbell delivery, due to delivery path and contention under a >>> large number of guest cores. >> To clarify, this is a hardware issue, right? >> >> Note that in practice this patch series wouldn't change much, because >> x2apic is enabled by default by userspace (it has better performance >> than memory-mapped APIC) and patch 1 in turn inhibits APICv if the guest >> has the X2APIC CPUID bit set. > QEMU will work fine with this option ON due to x2APIC, just like what > you said. If you feel other emulators using KVM will behave similarly, I > can revoke my concern. No, it's okay for now to leave it disabled. It would be nice if this information would be more easily available than by you lurking on the mailing list. :) Paolo
