From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by dpdk.org (Postfix) with ESMTP id 6771E3277 for ; Fri, 4 Nov 2016 14:09:25 +0100 (CET) Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP; 04 Nov 2016 06:09:21 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.31,443,1473145200"; d="scan'208";a="27468921" Received: from fmsmsx107.amr.corp.intel.com ([10.18.124.205]) by fmsmga005.fm.intel.com with ESMTP; 04 Nov 2016 06:09:21 -0700 Received: from fmsmsx119.amr.corp.intel.com (10.18.124.207) by fmsmsx107.amr.corp.intel.com (10.18.124.205) with Microsoft SMTP Server (TLS) id 14.3.248.2; Fri, 4 Nov 2016 06:09:20 -0700 Received: from shsmsx101.ccr.corp.intel.com (10.239.4.153) by FMSMSX119.amr.corp.intel.com (10.18.124.207) with Microsoft SMTP Server (TLS) id 14.3.248.2; Fri, 4 Nov 2016 06:09:20 -0700 Received: from shsmsx103.ccr.corp.intel.com ([169.254.4.139]) by SHSMSX101.ccr.corp.intel.com ([169.254.1.104]) with mapi id 14.03.0248.002; Fri, 4 Nov 2016 21:09:18 +0800 From: "Wang, Zhihong" To: Maxime Coquelin , Yuanhan Liu CC: "stephen@networkplumber.org" , "Pierre Pfister (ppfister)" , "Xie, Huawei" , "dev@dpdk.org" , "vkaplans@redhat.com" , "mst@redhat.com" Thread-Topic: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path Thread-Index: AQHSJjLIgzIjeGrkS0+qEKh9oEoL36Cr/zyAgAAg9YCAAA7sgIAP4USA//+BDwCAABccgIAAAIiAgAADH4CAAXEIoP//7duAgAVhEfCAAq9+AIABZX6AgAIH/aD//4ajgAAAEyqAABN0pMD//50GgP//aV+AgACwHQD//3fkAA== Date: Fri, 4 Nov 2016 13:09:17 +0000 Message-ID: <8F6C2BD409508844A0EFC19955BE09414E7DC793@SHSMSX103.ccr.corp.intel.com> References: <1474965769-24782-1-git-send-email-maxime.coquelin@redhat.com> <20161027103317.GM16751@yliu-dev.sh.intel.com> <0ba8f8c9-2174-b3c1-4f07-f6911bffa6cd@redhat.com> <20161027104621.GN16751@yliu-dev.sh.intel.com> <8F6C2BD409508844A0EFC19955BE09414E7D90C7@SHSMSX103.ccr.corp.intel.com> <88169067-290d-a7bb-ab2c-c9b8ec1b1ded@redhat.com> <8F6C2BD409508844A0EFC19955BE09414E7DA533@SHSMSX103.ccr.corp.intel.com> <8F6C2BD409508844A0EFC19955BE09414E7DC40F@SHSMSX103.ccr.corp.intel.com> <17d285a9-818c-b060-8969-daccb052dc1f@redhat.com> <7e1c8953-db15-f377-cece-85cb7169bb17@redhat.com> <8F6C2BD409508844A0EFC19955BE09414E7DC5B6@SHSMSX103.ccr.corp.intel.com> <8F6C2BD409508844A0EFC19955BE09414E7DC66F@SHSMSX103.ccr.corp.intel.com> <75d2c094-11e8-99aa-ccb5-60ded04047d7@redhat.com> In-Reply-To: <75d2c094-11e8-99aa-ccb5-60ded04047d7@redhat.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors support to the TX path X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 04 Nov 2016 13:09:26 -0000 > -----Original Message----- > From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com] > Sent: Friday, November 4, 2016 8:54 PM > To: Wang, Zhihong ; Yuanhan Liu > > Cc: stephen@networkplumber.org; Pierre Pfister (ppfister) > ; Xie, Huawei ; dev@dpdk.org; > vkaplans@redhat.com; mst@redhat.com > Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors suppor= t > to the TX path >=20 >=20 >=20 > On 11/04/2016 01:30 PM, Wang, Zhihong wrote: > > > > > >> -----Original Message----- > >> From: Maxime Coquelin [mailto:maxime.coquelin@redhat.com] > >> Sent: Friday, November 4, 2016 7:23 PM > >> To: Wang, Zhihong ; Yuanhan Liu > >> > >> Cc: stephen@networkplumber.org; Pierre Pfister (ppfister) > >> ; Xie, Huawei ; > dev@dpdk.org; > >> vkaplans@redhat.com; mst@redhat.com > >> Subject: Re: [dpdk-dev] [PATCH v4] vhost: Add indirect descriptors > support to the > >> TX path > >> > >> > >> > >>>>>> Hi Maxime, > >>>>>> > >>>>>> I did a little more macswap test and found out more stuff here: > >>>>> Thanks for doing more tests. > >>>>> > >>>>>> > >>>>>> 1. I did loopback test on another HSW machine with the same H/W, > >>>>>> and indirect_desc on and off seems have close perf > >>>>>> > >>>>>> 2. So I checked the gcc version: > >>>>>> > >>>>>> * Previous: gcc version 6.2.1 20160916 (Fedora 24) > >>>>>> > >>>>>> * New: gcc version 5.4.0 20160609 (Ubuntu 16.04.1 LTS) > >>>>> > >>>>> On my side, I tested with RHEL7.3: > >>>>> - gcc (GCC) 4.8.5 20150623 (Red Hat 4.8.5-11) > >>>>> > >>>>> It certainly contains some backports from newer GCC versions. > >>>>> > >>>>>> > >>>>>> On previous one indirect_desc has 20% drop > >>>>>> > >>>>>> 3. Then I compiled binary on Ubuntu and scp to Fedora, and as > >>>>>> expected I got the same perf as on Ubuntu, and the perf gap > >>>>>> disappeared, so gcc is definitely one factor here > >>>>>> > >>>>>> 4. Then I use the Ubuntu binary on Fedora for PVP test, then the > >>>>>> perf gap comes back again and the same with the Fedora binary > >>>>>> results, indirect_desc causes about 20% drop > >>>>> > >>>>> Let me know if I understand correctly: > >>> > >>> Yes, and it's hard to breakdown further at this time. > >>> > >>> Also we may need to check whether it's caused by certain NIC > >>> model. Unfortunately I don't have the right setup right now. > >>> > >>>>> Loopback test with macswap: > >>>>> - gcc version 6.2.1 : 20% perf drop > >>>>> - gcc version 5.4.0 : No drop > >>>>> > >>>>> PVP test with macswap: > >>>>> - gcc version 6.2.1 : 20% perf drop > >>>>> - gcc version 5.4.0 : 20% perf drop > >>>> > >>>> I forgot to ask, did you recompile only host, or both host and guest > >>>> testmpd's in your test? > >> > >>> Both. > >> > >> I recompiled testpmd on a Fedora 24 machine using GCC6: > >> gcc (GCC) 6.1.1 20160621 (Red Hat 6.1.1-3) > >> Testing loopback with macswap on my Haswell RHEL7.3 machine gives me > the > >> following results: > >> - indirect on: 7.75Mpps > >> - indirect off: 7.35Mpps > >> > >> Surprisingly, I get better results with indirect on my setup (I > >> reproduced the tests multiple times). > >> > >> Do you have a document explaining the tuning/config you apply to both > >> the host and the guest (isolation, HT, hugepage size, ...) in your > >> setup? > > > > > > The setup where it goes wrong: > > 1. Xeon E5-2699, HT on, turbo off, 1GB hugepage for both host and gues= t > On the Haswell machine (on which I don't have BIOS access), HT is on, > but I unplug siblings at runtime. > I also have 1G pages on both sides, and I isolate the cores used by both > testpmd and vCPUS. >=20 > > 2. Fortville 40G > > 3. Fedora 4.7.5-200.fc24.x86_64 > > 4. gcc version 6.2.1 > > 5. 16.11 RC2 for both host and guest > > 6. PVP, testpmd macswap for both host and guest > > > > BTW, I do see indirect_desc gives slightly better performance for loopb= ack > > in tests on other platforms, but don't know how PVP performs yet. > Interesting, other platforms are also Haswell/Broadwell? Yes, but with different OS. If you don't have the setup I can do more detailed profiling for the root cause next week, since my platform is the only one right now that reporting the drop. >=20 > For PVP benchmarks, are your figures with 0% pkt loss? No, for testpmd perf analysis it's not necessary in my opinion. I do tried low rate though, the result is the same. >=20 > Thanks, > Maxime >=20 > > > > > >> > >> Regards, > >> Maxime