From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from rgout01.bt.lon5.cpcloud.co.uk (rgout0106.bt.lon5.cpcloud.co.uk [65.20.0.126]) by dpdk.org (Postfix) with ESMTP id 4536A4C96 for ; Mon, 10 Sep 2018 20:51:10 +0200 (CEST) X-OWM-Source-IP: 10.110.12.2 () X-OWM-Env-Sender: terry.montague.1980@btinternet.com X-RazorGate-Vade-Classification: clean X-RazorGate-Vade-Verdict: clean 20 X-VadeSecure-score: verdict=clean score=20/300, class=clean X-SNCR-VADESECURE: CLEAN X-RazorGate-Vade-Verdict: clean 20 X-RazorGate-Vade-Classification: clean X-RazorGate-Vade: gggruggvucftvghtrhhoucdtuddrgedtjedrjedtgdduudeiucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecuueftkffvkffujffvgffngfevqffopdfqfgfvnecuuegrihhlohhuthemuceftddtnecuogfthfevqddquegrugfkmhhpohhrthgrnhgtvgculddvtddmnecujfgurhepfffhrhfvkffugggtkgfrsehmtdgtsgdttdejnecuhfhrohhmpedfthgvrhhrhidrmhhonhhtrghguhgvrdduleektdessghtihhnthgvrhhnvghtrdgtohhmfdcuoehtvghrrhihrdhmohhnthgrghhuvgdrudelkedtsegsthhinhhtvghrnhgvthdrtghomheqnecukfhppedutddruddutddruddvrddvpdekuddrudehgedrudekfedrfeelnecurfgrrhgrmhephhgvlhhopeifvggsmhgrihhlgedvrdgsthdrvgigthdrtghptghlohhuugdrtghordhukhdpihhnvghtpedutddruddutddruddvrddvpdhmrghilhhfrhhomhepoehtvghrrhihrdhmohhnthgrghhuvgdrudelkedtsegsthhinhhtvghrnhgvthdrtghomheqpdhrtghpthhtohepoehushgvrhhsseguphgukhdrohhrgheqnecuvehluhhsthgvrhfuihiivgeptd Received: from webmail42.bt.ext.cpcloud.co.uk (10.110.12.2) by rgout01.bt.lon5.cpcloud.co.uk (9.0.019.26-1) (authenticated as terry.montague.1980@btinternet.com) id 5B321EA006D13707 for users@dpdk.org; Mon, 10 Sep 2018 19:51:10 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=btinternet.com; s=btcpcloud; t=1536605470; bh=qfFamfoy2DykKaMtTmWpmUAsr6hpYzsm7btTpBDxS+Q=; h=Date:From:Reply-To:To:Message-ID:Subject:MIME-Version; b=lE/hg6qryDOEBxrIpZRtvvop5fyJFqCVET9+rSMfXePJTDA4wQMjXx4vq1NYH1idjaqV8OQAJwIYxJKX2kmjyYqgrgJoMEl1htyd0RDp3hFq6Qj4ZKceySLSsohDd1m13egDQAWKqqPWpMc0fGZ8LS6sYiECc7DKDG02c+RUT0A= Date: Mon, 10 Sep 2018 19:51:09 +0100 (BST) From: "terry.montague.1980@btinternet.com" To: users@dpdk.org Message-ID: <9772948.50847.1536605469967.JavaMail.defaultUser@defaultHost> MIME-Version: 1.0 Importance: 3 (Normal) X-Priority: 3 (Normal) X-Client-IP: IPv4[81.154.183.39] Epoch[1536605469948] Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: [dpdk-users] Too much data being sent with small packet and IXGBE X-BeenThere: users@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: terry.montague.1980@btinternet.com List-Id: DPDK usage discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 10 Sep 2018 18:51:10 -0000 Hi there, I'm trying to send a single IGMP control packet out of an Intel X550 to its connected router. I've looked at the packet in wireshark and its absolutely fine, the ethernet header, the ip header, the ipchecksum offload and the IGMP payload & checksum - there's nothing wrong with it. It is 46 bytes formatted and the pkt and data lengths of the allocated buffer are all set to 46 bytes. Its a 46 byte packet - end of! However.... what comes out of the interface is 60 bytes of data - the 46 bytes I want to send + 14 bytes of zeros. The 14 bytes is curiously equivalent to the size of an ethernet header, but I just cannot see how it is just being added on to the end of the packet data. Has anyone else observed this effect , or indeed know what's causing it ? Many thanks Terry. >From keith.wiles@intel.com Mon Sep 10 22:39:20 2018 Return-Path: Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by dpdk.org (Postfix) with ESMTP id B382058FA for ; Mon, 10 Sep 2018 22:39:19 +0200 (CEST) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga104.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 10 Sep 2018 13:39:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,357,1531810800"; d="scan'208";a="71878948" Received: from fmsmsx108.amr.corp.intel.com ([10.18.124.206]) by orsmga007.jf.intel.com with ESMTP; 10 Sep 2018 13:39:17 -0700 Received: from fmsmsx118.amr.corp.intel.com (10.18.116.18) by FMSMSX108.amr.corp.intel.com (10.18.124.206) with Microsoft SMTP Server (TLS) id 14.3.319.2; Mon, 10 Sep 2018 13:39:17 -0700 Received: from fmsmsx117.amr.corp.intel.com ([169.254.3.210]) by fmsmsx118.amr.corp.intel.com ([169.254.1.229]) with mapi id 14.03.0319.002; Mon, 10 Sep 2018 13:39:17 -0700 From: "Wiles, Keith" To: "terry.montague.1980@btinternet.com" CC: "users@dpdk.org" Thread-Topic: [dpdk-users] Too much data being sent with small packet and IXGBE Thread-Index: AQHUSTdFYua0UPViY0GbT5460tuaUaTqb5eA Date: Mon, 10 Sep 2018 20:39:16 +0000 Message-ID: References: <9772948.50847.1536605469967.JavaMail.defaultUser@defaultHost> In-Reply-To: <9772948.50847.1536605469967.JavaMail.defaultUser@defaultHost> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.254.188.247] Content-Type: text/plain; charset="us-ascii" Content-ID: Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-users] Too much data being sent with small packet and IXGBE 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: , X-List-Received-Date: Mon, 10 Sep 2018 20:39:20 -0000 > On Sep 10, 2018, at 1:51 PM, terry.montague.1980@btinternet.com wrote: >=20 > Hi there, > I'm trying to send a single IGMP control packet out of an Intel X550 to i= ts connected router. > I've looked at the packet in wireshark and its absolutely fine, the ether= net header, the ip header, the ipchecksum offload and the IGMP payload & ch= ecksum - there's nothing wrong with it. > It is 46 bytes formatted and the pkt and data lengths of the allocated bu= ffer are all set to 46 bytes. Its a 46 byte packet - end of! > However.... what comes out of the interface is 60 bytes of data - the 46= bytes I want to send + 14 bytes of zeros. > The 14 bytes is curiously equivalent to the size of an ethernet header, b= ut I just cannot see how it is just being added on to the end of the packet= data. > Has anyone else observed this effect , or indeed know what's causing it ? Not sure what you are doing, but the smallest packet on ethernet is 60 byte= s + 4 bytes CRC for 64 bytes total. Normally anything less then 60 bytes + = CRC is called a runt packet and are discarded. The NIC is padding the data = to 60 bytes then adds the 4 byte CRC. Hope that helps. > Many thanks > Terry. Regards, Keith