On Sun, Apr 07, 2013 at 12:30:38PM +0300, Gleb Natapov wrote: > On Thu, Apr 04, 2013 at 04:14:57PM +0300, Gleb Natapov wrote: > > > > > > > >>> is to move to MMIO only when PIO address space is exhausted. For PCI > > > >>> it > > > >>> will be never, for PCI-e it will be after ~16 devices. > > > >> > > > >> Ok, let's go back a step here. Are you actually able to measure any > > > >> speed in performance with this patch applied and without when going > > > >> through MMIO kicks? > > > >> > > > >> > > > > That's the question for MST. I think he did only micro benchmarks till > > > > now and he already posted his result here: > > > > > > > > mmio-wildcard-eventfd:pci-mem 3529 > > > > mmio-pv-eventfd:pci-mem 1878 > > > > portio-wildcard-eventfd:pci-io 1846 > > > > > > > > So the patch speedup mmio by almost 100% and it is almost the same as > > > > PIO. > > > > > > Those numbers don't align at all with what I measured. > > I am trying to run vmexit test on AMD now, but something does not work > > there. Next week I'll fix it and see how AMD differs, bit on Intel those > > are the > > numbers. > > > The numbers are: > vmcall 1921 > inl_from_kernel 4227 > outl_to_kernel 2345 > > outl is specifically optimized to not go through the emulator since it > is used for virtio kick. mmio-pv-eventfd is the same kind of > optimization but for mmio. > > -- > Gleb.
Hmm so on AMD it's more like 20% overhead, like ARM. -- MST _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
