On Thu, May 28, 2020 at 04:59:06PM -0600, Alex Williamson wrote: > 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, > Yes, I think so, but I haven't looked into it yet. Thanks Yan
