From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <stephen@networkplumber.org>
Received: from mail-qk0-f174.google.com (mail-qk0-f174.google.com
 [209.85.220.174]) by dpdk.org (Postfix) with ESMTP id CDCBF5A83
 for <dev@dpdk.org>; Wed, 10 Jun 2015 02:49:04 +0200 (CEST)
Received: by qkoo18 with SMTP id o18so17927885qko.1
 for <dev@dpdk.org>; Tue, 09 Jun 2015 17:49:04 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
 d=1e100.net; s=20130820;
 h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to
 :references:mime-version:content-type:content-transfer-encoding;
 bh=zNUTow4HupVV3CfjPG0EtKoLMJ7oOqew6vVD2QQS9DQ=;
 b=Kqtw4EC1g3a9SHVV1ywBeAFp702p3fOGH9zYsVhXpakBX4rCsSCeek2pHWF2XbDQbW
 1N8dC2l71ksGJQ51fL6G+y5iSpsP0aFQH3wsg0eb9GWogTEdmaC4jCoBcQNNeiCzKyi9
 xU1/uqF9ZihdtjXu5v6y6boyOKBdW8x4eFMLEWOYqJ5l6T6WlKAE08utNoqYOv21xKnX
 Z29dBZIsGB9HmoqG/p9olzhaRGegvFvNJzn32tk3agaw+c8wQcNV+YddEOu1nQdBC/kg
 d8Rm7y0thLtDbc28a6KyOqgb99ED0AXuRhcrr0GrK//shojUVTZh3FUxZ5BQ62mzLdZt
 Duug==
X-Gm-Message-State: ALoCoQn+VFVzPpeoeUgJYxAbx5F1iJKKUClqkZaGfUFMOJ3nuIHzMkpWRqgUFKvQox8ZwNQFQXJ7
X-Received: by 10.140.81.16 with SMTP id e16mr455712qgd.75.1433897344426;
 Tue, 09 Jun 2015 17:49:04 -0700 (PDT)
Received: from urahara (static-50-53-82-155.bvtn.or.frontiernet.net.
 [50.53.82.155])
 by mx.google.com with ESMTPSA id w67sm3466038qgw.41.2015.06.09.17.49.03
 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128);
 Tue, 09 Jun 2015 17:49:04 -0700 (PDT)
Date: Tue, 9 Jun 2015 17:49:06 -0700
From: Stephen Hemminger <stephen@networkplumber.org>
To: "Tim Deng" <dpdkdev@126.com>
Message-ID: <20150609174906.075e76c8@urahara>
In-Reply-To: <cb61a61.2dc8.14dcd0a7582.Coremail.dpdkdev@126.com>
References: <cb61a61.2dc8.14dcd0a7582.Coremail.dpdkdev@126.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: quoted-printable
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] Is vhost vring_avail size tunable?
X-BeenThere: dev@dpdk.org
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: patches and discussions about DPDK <dev.dpdk.org>
List-Unsubscribe: <http://dpdk.org/ml/options/dev>,
 <mailto:dev-request@dpdk.org?subject=unsubscribe>
List-Archive: <http://dpdk.org/ml/archives/dev/>
List-Post: <mailto:dev@dpdk.org>
List-Help: <mailto:dev-request@dpdk.org?subject=help>
List-Subscribe: <http://dpdk.org/ml/listinfo/dev>,
 <mailto:dev-request@dpdk.org?subject=subscribe>
X-List-Received-Date: Wed, 10 Jun 2015 00:49:05 -0000

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.