From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dispatch1-us1.ppe-hosted.com (dispatch1-us1.ppe-hosted.com [148.163.129.52]) by dpdk.org (Postfix) with ESMTP id D02211B1FF for ; Fri, 20 Oct 2017 14:23:22 +0200 (CEST) Received: from pure.maildistiller.com (dispatch1.mdlocal [10.7.20.164]) by dispatch1-us1.ppe-hosted.com (Proofpoint Essentials ESMTP Server) with ESMTP id 2A2CD60055; Fri, 20 Oct 2017 12:23:22 +0000 (UTC) X-Virus-Scanned: Proofpoint Essentials engine Received: from mx2-us3.ppe-hosted.com (us4-filterqueue.mdlocal [10.7.20.246]) by pure.maildistiller.com (Proofpoint Essentials ESMTP Server) with ESMTPS id C396C22004D; Fri, 20 Oct 2017 12:23:20 +0000 (UTC) Received: from webmail.solarflare.com (uk.solarflare.com [193.34.186.16]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx2-us3.ppe-hosted.com (Proofpoint Essentials ESMTP Server) with ESMTPS id 6A6AE80065; Fri, 20 Oct 2017 12:23:20 +0000 (UTC) Received: from [192.168.38.17] (84.52.114.114) by ukex01.SolarFlarecom.com (10.17.10.4) with Microsoft SMTP Server (TLS) id 15.0.1044.25; Fri, 20 Oct 2017 13:23:15 +0100 To: Bruce Richardson CC: Yongseok Koh , "dev@dpdk.org" References: <20171020115823.GA21216@bricha3-MOBL3.ger.corp.intel.com> From: Andrew Rybchenko Message-ID: <56be56b2-092a-ddc1-85ef-6e14065382bd@solarflare.com> Date: Fri, 20 Oct 2017 15:23:10 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171020115823.GA21216@bricha3-MOBL3.ger.corp.intel.com> Content-Language: en-GB X-Originating-IP: [84.52.114.114] X-ClientProxiedBy: ocex03.SolarFlarecom.com (10.20.40.36) To ukex01.SolarFlarecom.com (10.17.10.4) X-TM-AS-Product-Ver: SMEX-11.0.0.1191-8.100.1062-23406.003 X-TM-AS-Result: No--7.308900-0.000000-31 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No X-MDID: 1508502201-LheEXZHlBsy7 Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Subject: Re: [dpdk-dev] Requirement of minimum Rx burst size for PMDs X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 20 Oct 2017 12:23:23 -0000 On 10/20/2017 02:58 PM, Bruce Richardson wrote: > On Fri, Oct 20, 2017 at 01:07:17PM +0300, Andrew Rybchenko wrote: >> On 10/20/2017 04:18 AM, Yongseok Koh wrote: >>> Therefore, how about adding min_rx/tx_burst_sz in struct rte_eth_dev_info and >>> have PMDs fill it in on dev_ops->dev_infos_get() so as to make apps comply with >>> it. >> Just for my understand, what should happen if application wants to send only >> one packet? 5 packets? 33? 35? > I actually think there is a mistake in the original mails. At least for > Intel PMDs there is no restriction on min TX burst sizes in any code > path. The vector RX on the other hand does require a minimum number of empty > buffers to be passed to it, so you need to request no fewer than 4 > packets in a burst. If only one packet is available that will still be > returned to you, but you must request at least 4 I see. The thread subject says Rx, but Tx (min_tx_burst_sz) is mentioned above. If Tx is mentioned by mistake, it is clear now. Andrew.