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Date: Thu, 1 Oct 2015 07:55:20 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
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Cc: "dev@dpdk.org" <dev@dpdk.org>, Avi Kivity <avi@scylladb.com>
Subject: Re: [dpdk-dev] Having troubles binding an SR-IOV VF to
 uio_pci_generic on Amazon instance
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On Thu, 1 Oct 2015 13:14:08 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Thu, Oct 01, 2015 at 12:43:53PM +0300, Avi Kivity wrote:
> > >There were some tentative to get it for other (older) drivers, named
> > >'bifurcated drivers', but it is stalled.
> > 
> > IIRC they still exposed the ring to userspace.
> 
> How much would a ring write syscall cost? 1-2 microseconds, isn't it?

The per-packet budget at 10G is 62ns, a syscall just doesn't cut it.