Re: [RFC v4 PATCH 32/49] multi-process: Use separate MMIO communication channel

[Jag Raman]

On 11/11/2019 11:21 AM, Stefan Hajnoczi wrote:
> On Thu, Oct 24, 2019 at 05:09:13AM -0400, Jagannathan Raman wrote:
> > Using a separate communication channel for MMIO helps
> > with improving Performance
>
> Why?

Typical initiation of IO operations involves multiple MMIO accesses per
IO operation. In some legacy devices like LSI, the completion of the IO
operations is also accomplished by polling on MMIO registers. Therefore,
MMIO traffic can be hefty in some cases and contribute to Performance.

Having a dedicated channel for MMIO ensures that it doesn't have to
compete with other messages to the remote process, especially when there
are multiple devices emulated by a single remote process.

Thanks!
--
Jag

>