On Wed, 27 May 2020 09:48:22 +0100 "Dr. David Alan Gilbert" <dgilbert@xxxxxxxxxx> wrote: > * Yan Zhao (yan.y.zhao@xxxxxxxxx) wrote: > > BTW, for viommu, the downtime data is as below. under the same network > > condition and guest memory size, and no running dirty data/memory produced > > by device. > > (1) viommu off > > single-round dirty query: downtime ~100ms > > Fine. > > > (2) viommu on > > single-round dirty query: downtime 58s > > Youch. Double Youch! But we believe this is because we're getting the dirty bitmap one IOMMU leaf page at a time, right? We've enable the kernel to get a dirty bitmap across multiple mappings, but QEMU isn't yet taking advantage of it. Do I have this correct? Thanks, Alex
