>>> On 25.11.15 at 11:28, <andrew.coop...@citrix.com> wrote: > The problem is that SandyBridge IOMMUs advertise 2M support and do > function with it, but cannot cache 2MB translations in the IOTLBs. > > As a result, attempting to use 2M translations causes substantially > worse performance than 4K translations.
Btw - how does this get explained? At a first glance, even if 2Mb translations don't get entered into the TLB, it should still be one less page table level to walk for the IOMMU, and should hence nevertheless be a benefit. Yet you even say _substantially_ worse performance results. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
