Re: [Qemu-devel] Why I advise against using ivshmem

[Stefan Hajnoczi]

On Tue, Jun 17, 2014 at 11:03:32AM +0200, David Marchand wrote:
> On 06/17/2014 04:54 AM, Stefan Hajnoczi wrote:
> >ivshmem has a performance disadvantage for guest-to-host
> >communication.  Since the shared memory is exposed as PCI BARs, the
> >guest has to memcpy into the shared memory.
> >
> >vhost-user can access guest memory directly and avoid the copy inside the 
> >guest.
> 
> Actually, you can avoid this memory copy using frameworks like DPDK.

I guess it's careful to allocate all packets in the mmapped BAR?

That's fine if you can modify applications but doesn't work for
unmodified applications using regular networking APIs.

Stefan

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