From mboxrd@z Thu Jan  1 00:00:00 1970
From: Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: Is vhost vring_avail size tunable?
Date: Tue, 9 Jun 2015 17:49:06 -0700
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To: "Tim Deng" <dpdkdev@126.com>
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On Sun, 7 Jun 2015 16:02:04 +0800 (CST)
"Tim Deng" <dpdkdev@126.com> wrote:

>=20
> Hi,
>=20
> Under heavy work load, I found there were some packet lost caused by
> "Failed=C2=A0to get enough desc from vring...", is there any way to get t=
he
> vring size larger?
>=20
> Thanks,
> Tim

One thing that could help the DPDK virtio driver would be to support
INDIRECT descriptors. By using that, it is possible to get 256 packets
into the 256 slots in QEMU.  Currently half the slots are taken by
headers.

The implementation of vhost driver likewise needs to get support
for INDIRECT descriptors and some other features in order to use slots
more efficiently.