From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: Re: [PATCH v3 0/5] vhost: optimize enqueue
Date: Thu, 22 Sep 2016 10:29:03 +0800
Message-ID: <20160922022903.GJ23158@yliu-dev.sh.intel.com>
References: <1471319402-112998-1-git-send-email-zhihong.wang@intel.com>
 <1471585430-125925-1-git-send-email-zhihong.wang@intel.com>
 <e6addeba-ffbc-baae-61c8-5b8e798c843e@redhat.com>
 <CAP4Qi3-cSgHDPC3Wne3RSL0t=Z-vhYUPsPWH6VAXsXsHYX6ShQ@mail.gmail.com>
 <8F6C2BD409508844A0EFC19955BE09414E7B5581@SHSMSX103.ccr.corp.intel.com>
 <CAP4Qi39-KD8pY-3M31asoDV+dja27XzFTsBMq9ignoawdL8=HQ@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Cc: "Wang, Zhihong" <zhihong.wang@intel.com>,
 Maxime Coquelin <maxime.coquelin@redhat.com>, "dev@dpdk.org" <dev@dpdk.org>
To: Jianbo Liu <jianbo.liu@linaro.org>
Return-path: <dev-bounces@dpdk.org>
Received: from mga09.intel.com (mga09.intel.com [134.134.136.24])
 by dpdk.org (Postfix) with ESMTP id 1952A374F
 for <dev@dpdk.org>; Thu, 22 Sep 2016 04:28:28 +0200 (CEST)
Content-Disposition: inline
In-Reply-To: <CAP4Qi39-KD8pY-3M31asoDV+dja27XzFTsBMq9ignoawdL8=HQ@mail.gmail.com>
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>
Errors-To: dev-bounces@dpdk.org
Sender: "dev" <dev-bounces@dpdk.org>

On Wed, Sep 21, 2016 at 08:54:11PM +0800, Jianbo Liu wrote:
> >> > My setup consists of one host running a guest.
> >> > The guest generates as much 64bytes packets as possible using
> >>
> >> Have you tested with other different packet size?
> >> My testing shows that performance is dropping when packet size is more
> >> than 256.
> >
> >
> > Hi Jianbo,
> >
> > Thanks for reporting this.
> >
> >  1. Are you running the vector frontend with mrg_rxbuf=off?
> >
> >  2. Could you please specify what CPU you're running? Is it Haswell
> >     or Ivy Bridge?
> >
> >  3. How many percentage of drop are you seeing?
> >
> > This is expected by me because I've already found the root cause and
> > the way to optimize it, but since it missed the v0 deadline and
> > requires changes in eal/memcpy, I postpone it to the next release.
> >
> > After the upcoming optimization the performance for packets larger
> > than 256 will be improved, and the new code will be much faster than
> > the current code.
> >
> 
> Sorry, I tested on an ARM server, but I wonder if there is the same
> issue for x86 platform.

Would you please provide more details? Say, answer the two left
questions from Zhihong?

Thanks.

	--yliu