From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jianbo Liu Subject: Re: [PATCH v3 0/5] vhost: optimize enqueue Date: Thu, 22 Sep 2016 13:47:45 +0800 Message-ID: References: <1471319402-112998-1-git-send-email-zhihong.wang@intel.com> <1471585430-125925-1-git-send-email-zhihong.wang@intel.com> <8F6C2BD409508844A0EFC19955BE09414E7B5581@SHSMSX103.ccr.corp.intel.com> <20160922022903.GJ23158@yliu-dev.sh.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: "Wang, Zhihong" , Maxime Coquelin , "dev@dpdk.org" To: Yuanhan Liu Return-path: Received: from mail-yw0-f175.google.com (mail-yw0-f175.google.com [209.85.161.175]) by dpdk.org (Postfix) with ESMTP id EF7F3298F for ; Thu, 22 Sep 2016 07:47:46 +0200 (CEST) Received: by mail-yw0-f175.google.com with SMTP id t67so84053580ywg.3 for ; Wed, 21 Sep 2016 22:47:46 -0700 (PDT) In-Reply-To: <20160922022903.GJ23158@yliu-dev.sh.intel.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" On 22 September 2016 at 10:29, Yuanhan Liu wrote: > 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? >> > Yes, my testing is mrg_rxbuf=off, but not vector frontend PMD. >> > 2. Could you please specify what CPU you're running? Is it Haswell >> > or Ivy Bridge? >> > It's an ARM server. >> > 3. How many percentage of drop are you seeing? The testing result: size (bytes) improvement (%) 64 3.92 128 11.51 256 24.16 512 -13.79 1024 -22.51 1500 -12.22 A correction is that performance is dropping if byte size is larger than 512. >> > >> > 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