From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bruce Richardson Subject: Re: Requirement of minimum Rx burst size for PMDs Date: Fri, 20 Oct 2017 12:58:23 +0100 Message-ID: <20171020115823.GA21216@bricha3-MOBL3.ger.corp.intel.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Yongseok Koh , "dev@dpdk.org" To: Andrew Rybchenko Return-path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id 213E81B224 for ; Fri, 20 Oct 2017 13:58:27 +0200 (CEST) Content-Disposition: inline In-Reply-To: List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" 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 Reagrds, /Bruce