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 65396A0C3F; Sat, 12 Jun 2021 09:01:34 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id D21A74014F; Sat, 12 Jun 2021 09:01:33 +0200 (CEST) Received: from szxga02-in.huawei.com (szxga02-in.huawei.com [45.249.212.188]) by mails.dpdk.org (Postfix) with ESMTP id BB7364003F for ; Sat, 12 Jun 2021 09:01:32 +0200 (CEST) Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.53]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4G27pS0tCQz6xYC; Sat, 12 Jun 2021 14:58:24 +0800 (CST) Received: from dggpeml500024.china.huawei.com (7.185.36.10) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Sat, 12 Jun 2021 15:01:30 +0800 Received: from [127.0.0.1] (10.40.190.165) 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 15.1.2176.2; Sat, 12 Jun 2021 15:01:30 +0800 From: fengchengwen To: Thomas Monjalon , Ferruh Yigit CC: "dev@dpdk.org" , , , "Richardson, Bruce" Message-ID: <27a77ca8-9406-1737-ff84-774b2ca561f7@huawei.com> Date: Sat, 12 Jun 2021 15:01:28 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.40.190.165] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500024.china.huawei.com (7.185.36.10) X-CFilter-Loop: Reflected Subject: [dpdk-dev] RFC: Kunpeng DMA driver API design decision 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 Sender: "dev" Hi all, We prepare support Kunpeng DMA engine under rawdev framework, and observed that there are two different implementations of the data plane API: 1. rte_rawdev_enqueue/dequeue_buffers which was implemented by dpaa2_qdma and octeontx2_dma driver. 2. rte_ioat_enqueue_xxx/rte_ioat_completed_ops which was implemented by ioat driver. Due to following consideration (mainly performance), we plan to implement API like ioat (not the same, have some differences) in data plane: 1. The rte_rawdev_enqueue_buffers use opaque buffer reference which is vendor's specific, so it needs first to translate application parameters to opaque pointer, and then driver writes the opaque data onto hardware, this may lead to performance problem. 2. rte_rawdev_xxx doesn't provide memory barrier API which may need to extend by opaque data (e.g. add flag to every request), this may introduce some complexity. Also the example/ioat was used to compare DMA and CPU-memcopy performance, Could we generalized it so that it supports multiple-vendor ? I don't know if the community accepts this kind of implementation, so if you have any comments, please provide feedback. Best Regards.