On 5/29/2020 4:29 AM, 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,
That's correct.
Thanks,
Kirti
