Re: [Qemu-devel] [PATCH] Inter-VM shared memory PCI device

Paul Brook
2010-03-11T12:21:24Z

> On 03/10/2010 07:41 PM, Paul Brook wrote:
> >>> You're much better off using a bulk-data transfer API that relaxes
> >>> coherency requirements. IOW, shared memory doesn't make sense for TCG
> >>
> >> Rather, tcg doesn't make sense for shared memory smp. But we knew that
> >> already.
> >
> > In think TCG SMP is a hard, but soluble problem, especially when you're
> > running guests used to coping with NUMA.
>
> Do you mean by using a per-cpu tlb? These kind of solutions are
> generally slow, but tcg's slowness may mask this out.

Yes.

> > TCG interacting with third parties via shared memory is probably never
> > going to make sense.
>
> The third party in this case is qemu.

Maybe. But it's a different instance of qemu, and once this feature exists I
bet people will use it for other things.

Paul