On 8/10/21 10:31 AM, Kirill A. Shutemov wrote: > On Tue, Aug 10, 2021 at 08:51:01AM -0700, Dave Hansen wrote: >> Let's say we have a 128GB VM. How much does faster does this approach >> reach userspace than if all memory was accepted up front? How much >> memory _could_ have been accepted at the point userspace starts running? > > Acceptance code is not optimized yet: we accept memory in 4k chunk which > is very slow because hypercall overhead dominates the picture. > > As of now, kernel boot time of 1 VCPU and 64TiB VM with upfront memory > accept is >20 times slower than with this lazy memory accept approach. That's a pretty big deal. > The difference is going to be substantially lower once we get it optimized > properly. What does this mean? Is this future work in the kernel or somewhere in the TDX hardware/firmware which will speed things up?
