From mboxrd@z Thu Jan  1 00:00:00 1970
From: santosh <santosh.shukla@caviumnetworks.com>
Subject: Re: [PATCH v2] vhost: adaptively batch small guest
 memory copies
Date: Sat, 9 Sep 2017 20:28:57 +0530
Message-ID: <8f9831eb-3673-fb6a-06c0-702c1d0e9d96@caviumnetworks.com>
References: <20170824021939.21306-1-tiwei.bie@intel.com>
 <20170908125046.28739-1-tiwei.bie@intel.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=windows-1252
Content-Transfer-Encoding: 7bit
Cc: yliu@fridaylinux.org, maxime.coquelin@redhat.com,
 Zhihong Wang <zhihong.wang@intel.com>, Zhiyong Yang <zhiyong.yang@intel.com>
To: Tiwei Bie <tiwei.bie@intel.com>, dev@dpdk.org
Return-path: <dev-bounces@dpdk.org>
Received: from NAM02-SN1-obe.outbound.protection.outlook.com
 (mail-sn1nam02on0079.outbound.protection.outlook.com [104.47.36.79])
 by dpdk.org (Postfix) with ESMTP id 7879B567C
 for <dev@dpdk.org>; Sat,  9 Sep 2017 16:59:16 +0200 (CEST)
In-Reply-To: <20170908125046.28739-1-tiwei.bie@intel.com>
List-Id: DPDK patches and discussions <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 Friday 08 September 2017 06:20 PM, Tiwei Bie wrote:
> This patch adaptively batches the small guest memory copies.
> By batching the small copies, the efficiency of executing the
> memory LOAD instructions can be improved greatly, because the
> memory LOAD latency can be effectively hidden by the pipeline.
> We saw great performance boosts for small packets PVP test.
>
> This patch improves the performance for small packets, and has
> distinguished the packets by size. So although the performance
> for big packets doesn't change, it makes it relatively easy to
> do some special optimizations for the big packets too.
>
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>
> Signed-off-by: Zhiyong Yang <zhiyong.yang@intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> This optimization depends on the CPU internal pipeline design.
> So further tests (e.g. ARM) from the community is appreciated.
>
> v2: s/burst_copy/batch_copy/g

In pvp setup for arm64 platform, no performance drop noticed with this patch but no significant performance gain either. Tested-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>