From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id 2E404A0096 for ; Wed, 8 May 2019 17:04:04 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 8434B374C; Wed, 8 May 2019 17:04:03 +0200 (CEST) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 5C3EC34F0 for ; Wed, 8 May 2019 17:04:02 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 May 2019 08:04:01 -0700 X-ExtLoop1: 1 Received: from fmsmsx107.amr.corp.intel.com ([10.18.124.205]) by orsmga001.jf.intel.com with ESMTP; 08 May 2019 08:04:00 -0700 Received: from fmsmsx154.amr.corp.intel.com (10.18.116.70) by fmsmsx107.amr.corp.intel.com (10.18.124.205) with Microsoft SMTP Server (TLS) id 14.3.408.0; Wed, 8 May 2019 08:03:26 -0700 Received: from fmsmsx117.amr.corp.intel.com ([169.254.3.26]) by FMSMSX154.amr.corp.intel.com ([169.254.6.159]) with mapi id 14.03.0415.000; Wed, 8 May 2019 08:03:25 -0700 From: "Wiles, Keith" To: hirok borah CC: Anupama Laxmi , "users@dpdk.org" Thread-Topic: [dpdk-users] UDP packet transmission issue - DPDK 18.08 Thread-Index: AQHU9y9clSoOGSL0j0qzYQapRzJp4aZhWTOAgAB6GACAAAg8gIAACdGA Date: Wed, 8 May 2019 15:03:25 +0000 Message-ID: References: <95C022B5-CB05-4C30-A57A-A9B183548107@intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.254.105.50] Content-Type: text/plain; charset="us-ascii" Content-ID: <6E4003AE60CAF7418E89CB43F4796148@intel.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-users] UDP packet transmission issue - DPDK 18.08 X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: users-bounces@dpdk.org Sender: "users" Hi Hirok, > On May 8, 2019, at 9:28 AM, hirok borah wrote: >=20 > Thanks Keith for sharing the info. >=20 > But as also stated by Anupama, the problem here is with KNI.=20 >=20 > When UDP packet of certain length, say 730, is written to kni, it is gett= ing dropped. >=20 > Whereas UDP of length say 60, does not have any issues, it goes to kernel= . >=20 > And this issue was not seen with previous versions, only seen when we upg= raded to v18.08 I have not used KNI per say, but it also does not seem to understand UDP or= TCP or any another protocol sent only mbufs. Unless I am wrong that means = the application must construct the UDP frame to be sent to the kernel and s= etup the mbuf headers correctly, right? Even the KNI test code does not see= m to understand UDP frames, just looking at the code anyway. Using testpmd or traffic generators to send a UDP frame to KNI interface an= d see if the problem still exists does seem like a reasonable direction to = eliminate possible problems. Beyond that I can not help, take my suggestions as you see fit. Thanks >=20 > Regards > -Hirok >=20 >=20 > On Wed, May 8, 2019, 7:28 PM Wiles, Keith wrote: >=20 >=20 > > On May 8, 2019, at 1:41 AM, hirok borah wrote: > >=20 > > Hi All, > >=20 > > Do we have any resolution for this issue yet ? > > This looks like a defect in DPDK 18.08. >=20 > DPDK does not understand UDP/TCP or any L4 Packet per say, it only sends = the packets constructed in the application. It will send the packets as def= ined and the only place DPDK tries to determine the packet type is when it = receives the packet which in this case is the kernel. >=20 > I do not use testpmd much, but use pktgen-dpdk for my work. Please try wi= th testpmd or pktgen or TRex or moongen and see if the problem still exists= . > >=20 > > Plz share if anyone have any inputs on this issue. > >=20 > > Regards > > Hirok > >=20 > > On Sat, Apr 20, 2019 at 9:41 AM Anupama Laxmi > > wrote: > >=20 > >> We have recently upgraded to DPDK 18.08 version. After upgrading to th= e > >> latest version observing issue with UDP packets transmission errors fo= r few > >> packets ( UDP size 736 bytes) .With older version of DPDK we never fa= ced > >> this issue. > >>=20 > >> Attaching the filtered tcpdump which shows "Bad UDP length > IP payloa= d > >> length" for one such packet. > >>=20 > >> No issue observed while transferring UDP packets with size 28 bytes an= d 48 > >> bytes. I tried to print the packet length calculation in my program ju= st > >> before sending it out to the Kernel using rte_kni_tx_burst. The packet > >> length calculation seems correct to me. > >>=20 > >> 1.) > >> size_udp:48 > >> sizeof(struct udp_hdr):8 > >> size_ApplMsg:40 > >> udphdr->dgram_len:12288 > >> m->data_len:82 > >> size_ip:68 > >> l2_data_shift:14 > >>=20 > >> 2.) > >> size_udp:28 > >> sizeof(struct udp_hdr):8 > >> size_ApplMsg:20 > >> udphdr->dgram_len:7168 > >> m->data_len:62 > >> ip->total_length:12288 > >> size_ip:48 > >> l2_data_shift:14 > >>=20 > >> *** Packets with UDP size 736 are not getting transmitted to the > >> receiving end and getting dropped. > >>=20 > >> 3.) > >> size_udp:736 > >> sizeof(struct udp_hdr):8 > >> size_ApplMsg:728 > >> udphdr->dgram_len:57346 > >> m->data_len:770 > >> size_ip:756 > >> l2_data_shift:14 > >>=20 > >> Also MTU is set to 1500 in my program. So it shouldn't be an issue to > >> transfer 736 bytes UDP data which is less than 1500 bytes MTU. > >>=20 > >> Looks like the kernel is dropping this packet. > >>=20 > >> So I tried to increase the kernel buffer size but that didn't help. > >>=20 > >> netstat -su -> output shows 0 send/receive buffer errors. > >>=20 > >>=20 > >> What has changed in DPDK 18.08 with respect to UDP packets? Please sug= gest > >> if I need to consider tuning udp ( using new API ) , offloading udp > >> traffic(new offload flags) to resolve this issue. > >>=20 > >> Thanks, > >> -------------- next part -------------- > >> A non-text attachment was scrubbed... > >> Name: bad_udp_length.png > >> Type: image/png > >> Size: 56015 bytes > >> Desc: not available > >> URL: < > >> http://mails.dpdk.org/archives/users/attachments/20190420/f5dd6779/att= achment.png > >>>=20 > >>=20 > >=20 > >=20 > > --=20 > > Regards, > > -Hirok >=20 > Regards, > Keith >=20 Regards, Keith