On Thu, Jul 25, 2019 at 04:13:13PM +0200, Paolo Bonzini wrote: > On 25/07/19 15:54, Michael S. Tsirkin wrote: > >> FWIW the "PCI tax" seems to be ~10 ms in QEMU, ~10 ms in the firmware(*) > >> and ~25 ms in the kernel. > > How did you measure the qemu time btw? > > > > It's QEMU startup, but not QEMU altogether. For example the time spent > in memory.c when a BAR is programmed is not part of those 10 ms. > > So I just computed q35 qemu startup - microvm qemu startup, it's 65 vs > 65 ms. > > Paolo
Oh so it could be eventfd or whatever, just as well. I actually wonder whether we spend much time within synchronize_* calls. eventfd triggers this a lot of times. How about ioeventfd=off? Does this speed up things? -- MST