From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 2C81AA0545; Thu, 15 Dec 2022 13:46:51 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 1FAB440684; Thu, 15 Dec 2022 13:46:51 +0100 (CET) Received: from szxga03-in.huawei.com (szxga03-in.huawei.com [45.249.212.189]) by mails.dpdk.org (Postfix) with ESMTP id 7E31940223 for ; Thu, 15 Dec 2022 13:46:48 +0100 (CET) Received: from dggpeml500024.china.huawei.com (unknown [172.30.72.57]) by szxga03-in.huawei.com (SkyGuard) with ESMTP id 4NXsMt3FtRzJpNf; Thu, 15 Dec 2022 20:43:06 +0800 (CST) Received: from [10.67.100.224] (10.67.100.224) by dggpeml500024.china.huawei.com (7.185.36.10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.34; Thu, 15 Dec 2022 20:46:45 +0800 Subject: Re: Question about add ethdev loopback set API To: Ferruh Yigit CC: "dev@dpdk.org" , Andrew Rybchenko , Ori Kam , Thomas Monjalon References: <1109431c-2b18-cc02-5e36-5c1e2d298a82@amd.com> <2d70ef33-5cc8-f56e-91c1-a44fd5450ba2@huawei.com> From: fengchengwen Message-ID: <3fa49fba-4eaf-afd4-7677-9a50713eca04@huawei.com> Date: Thu, 15 Dec 2022 20:46:45 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.100.224] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500024.china.huawei.com (7.185.36.10) X-CFilter-Loop: Reflected X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org On 2022/12/14 18:38, Ferruh Yigit wrote: > On 12/14/2022 7:25 AM, fengchengwen wrote: >> On 2022/12/13 19:25, Ferruh Yigit wrote: >>> On 12/13/2022 10:04 AM, fengchengwen wrote: >>>> Hi Ferruh, >>>> >>>> During the test, we need to delineate where go wrong when encountered >>>> e.g. CRC error. In this scenario, loopback is useful. >>>> >>>> I think we can add a loopback set API which could set inner or outer loop, >>>> and user can use telemetry to set the loopback in the above scenario. >>>> >>>> I'd like to hear your opinion about add a loopback set API. >>>> >>> >>> Hi Chengwen, >>> >>> Is the intention to test ethdev layer or driver? >>> >>> It is possible to use ring vdev to create a loopback and to test ethdev >>> layer. >>> >>> For driver, it can be possible to create physical loopback connection, >>> or even can implement loopback Rx/Tx burst functions in driver. >>> Using another host to send/receive packets to DUT (device under test) is >>> another approach. >>> >>> >>> What kind of loopback implementation do you have in your mind? >> >> Mainly MAC layer and lower physical layer: >> >> -------- --------------- ------------ ---------- -------------------- >> | | | - rx | | - rx - | | - rx - | | | >> | Host | - | MAC | - | SerDes | - | PHY | ==== | Packet Generator | >> | | | - tx | | - tx - | | - tx - | | | >> -------- --------------- ------------ ---------- -------------------- >> >> The support loopback in hns3 platform: >> Inner loopback subtypes: which host send pkts and recv and then verify: >> Serdes tx to rx >> PHY tx to rx >> >> Outer loopback subtypes: which Packet-Generator send pkts and recv and then verify: >> MAC tx to rx >> >> I think we could support the above loopback types, and maybe other PMD platform support >> more loopback types. >> > > There is a 'lpbk_mode' field of "struct rte_eth_conf", to configure > loopback in 'rte_eth_dev_configure()', > but it isn't fine grained to define the possible modes you mentioned > above. Currently '0' means loopback disabled and non zero means it is > enabled, details left to drivers. > > 'lpbk_mode' is 32bit, we have space to define detailed loopback modes. Emm, I found the lpbk_mode is not defined in a unified manner, which is vendor specified. > > > Having loopback configuration in 'rte_eth_dev_configure()' requires port > to stop and reconfigure to enable/disable loopback. > If it is possible to change loopback behavior without full > reconfiguration cycle, we can add two new APIs to enable/disable > loopback. But this has the downside of two different APIs change same > config, and we had problems related this in the past. Yes, the 'use rte_eth_dev_configure() to config loopback' is inflexible, and I also notice the testpmd command "set tx loopback port-id on/off", and it invoke PMD's public API which is rte_pmd_ixgbe/i40e/bnxt/dpaa_set_tx_loopback. According to this information, loopback needs to be configured during running. So I suggest add one API: int rte_eth_dev_set_loopback(uint16_t port_id, uint32_t lpbk_mode), and costraint this API can only invoke when port is started, if turn off (lpbk_mode==0) then should recovering rte_eth_conf's lpbk_mode. Also the lpbk_mode is vendor specified. > > > > Also there is a hairpin feature in ethdev, that connects Rx queue back > to Tx queue, but not sure if that justifies your "MAC tx ro rx" testcase. > > > . >