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 23D7343889; Thu, 11 Jan 2024 02:55:11 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id AE68B40278; Thu, 11 Jan 2024 02:55:10 +0100 (CET) Received: from szxga06-in.huawei.com (szxga06-in.huawei.com [45.249.212.32]) by mails.dpdk.org (Postfix) with ESMTP id AECE340266 for ; Thu, 11 Jan 2024 02:55:08 +0100 (CET) Received: from mail.maildlp.com (unknown [172.19.88.234]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4T9SQy1NkYz1wn5M; Thu, 11 Jan 2024 09:54:50 +0800 (CST) Received: from dggpeml500024.china.huawei.com (unknown [7.185.36.10]) by mail.maildlp.com (Postfix) with ESMTPS id 7FC6414025A; Thu, 11 Jan 2024 09:55:06 +0800 (CST) Received: from [10.67.121.161] (10.67.121.161) 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 15.1.2507.35; Thu, 11 Jan 2024 09:55:06 +0800 Subject: Re: [PATCH] ethdev: add dump regs for telemetry To: Ferruh Yigit , Jie Hai , , Thomas Monjalon , Andrew Rybchenko , Bruce Richardson CC: , References: <20231214015650.3738578-1-haijie1@huawei.com> <8632690b-5e85-43fb-9121-a8910074726d@amd.com> <359de0d6-90c4-aaea-f186-574d04a31c2a@huawei.com> <33d1d451-95ea-48fe-a6ec-b86976ba5130@amd.com> <1dfc96a4-9471-4f2a-a835-72da95e6273e@amd.com> From: fengchengwen Message-ID: <3c2f311d-6614-90b9-610d-d53b0c3b72f5@huawei.com> Date: Thu, 11 Jan 2024 09:55:06 +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: <1dfc96a4-9471-4f2a-a835-72da95e6273e@amd.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.67.121.161] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To dggpeml500024.china.huawei.com (7.185.36.10) 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 Hi Ferruh, On 2024/1/10 20:15, Ferruh Yigit wrote: > On 1/10/2024 1:38 AM, fengchengwen wrote: >> Hi Ferruh, >> >> On 2024/1/10 2:06, Ferruh Yigit wrote: >>> On 1/9/2024 2:19 AM, Jie Hai wrote: >>>> On 2023/12/14 20:49, Ferruh Yigit wrote: >>>>> On 12/14/2023 1:56 AM, Jie Hai wrote: >>>>>> The ethdev library now registers a telemetry command for >>>>>> dump regs. >>>>>> >>>>>> An example usage is shown below: >>>>>> --> /ethdev/regs,test >>>>>> { >>>>>>    "/ethdev/regs": { >>>>>>      "regs_offset": 0, >>>>>>      "regs_length": 3192, >>>>>>      "regs_width": 4, >>>>>>      "device_version": "0x1080f00", >>>>>>      "regs_file": "port_0_regs_test" >>>>>>    } >>>>>> } >>>> >>>>> >>>>> Above code writes register data to a file. >>>>> >>>>> I am not sure about this kind of usage of telemetry command, that it >>>>> cause data to be written to a file. >>>>> >>>>> My understanding is, telemetry usage is based on what telemetry client >>>>> receives. >>>>> What do you think just keep the 'reg_info' fields excluding data to the >>>>> file? >>>>> >>>>> .Hi, Ferruh >>>> >>>> I tried to write all register information to telemetry data, >>>> but gave up because some drivers had too many registers (eg.ixgbe) >>>> to carry. Therefore, the writing data to file approach is selected. >>>> >>>> When we query a register, the register content is the key. >>>> The information such as the width and length is only auxiliary >>>> information. If the register data cannot be obtained, the auxiliary >>>> information is optional. So I don't think register data should be removed. >>>> >>>> In my opinion, writing a file is a more appropriate way to do it. >>>> I wonder if there's a better way. >>>> >>>> >>> >>> Is there a usecase to get register information from telemetry interface? >> >> Among the available tools: >> 1, ethtool/proc-info: should use multi-process mechanism to connect to the main process >> 2, telemetry: easier, lighter load, and it don't need re-probe the ethdev in the secondary process, >> and also cost more resource, like hugepage, cores. >> >> From our users, they prefer use the second 'telemetry', so I think we should move >> more status-query-points to telemetry. >> >> As for this question, I think it's okay to get register info from telemetry. >> >> >> >> Another question, we have some internal registers, which: >> 1. Is not suitable expose by xstats, because they may includes configuration >> 2. Is not suitable expose by dumps, because this dumps is hard to understand (because it only has value). >> >> So we plan to add some telemetry points in the driver itself, so we could display them like xstats: >> "xxxx" : 0x1234 >> "yyyy" : 0x100 >> >> Will the community accept this kind of telemetry points which limit one driver ? >> > > Hi Chengwen, > > I see there is a usecase/requirement. > > With this patch, even using file, only register values are dumped and > isn't it hard to find value of specific register? > > ("xxxx" : 0x1234) approach looks better, but instead of making this > telemetry support for specific driver, what about making it in two steps. > > First add new dev_ops, (or update existing one), to get registers with > "name: value" format, (in a way to allow empty name), or even perhaps > "name: offset, value" format. > And in second stage add telemetry support around it. > (Name being optional lets us wrap exiting 'get_reg' dev_ops with new one) > > When adding dev_ops, it may get an additional 'filter' parameter, to get > only subset of regs, like "mac*" to get regs name staring with "mac", > this may help for the cases there are too many registers you mentioned. > > Anyway, we can discuss more about its design, but what do you think > about first having a dev_ops for this? I prefer extend struct rte_dev_reg_info, like this: struct rte_eth_reg_name { char name[RTE_ETH_REG_NAME_SIZE]; }; struct rte_dev_reg_info { void *data; /**< Buffer for return registers */ uint32_t offset; /**< Start register table location for access */ uint32_t length; /**< Number of registers to fetch */ uint32_t width; /**< Size of device register */ uint32_t version; /**< Device version */ /* Note: below two fields are new added. */ char *filter; /**< Filter for target subset of registers. This field could affects register selection for data/length/name. */ struct rte_eth_reg_name *names; /**< Registers name saver. */ }; For driver which don't identify the new filter and names fields: 1. .get_reg return the all registers value. 2. and driver will not touch the name fields. 3. rte_eth_dev_get_reg_info() could detect name fileds not filled, and then it fill with default names, e.g. offset-1/offset-2/... For driver which identify the new filter and names fields: 1. rte_eth_dev_get_reg_info() will return filtered register's value and also their names. So that those which invoke rte_eth_dev_get_reg_info() could extra prepare names, and it call the same API will get data and name. Add one new .get_reg_name ops and corresponding API like: rte_eth_dev_get_reg_name() could also feasible. But I think the rte_eth_dev_get_reg_info()'s name is too broad, the info could includes value and also it's name. So I prefer not add one new ops. Another question? what are the supported values of filters ? I prefer report by dev_info ops, something like a string array end with NULL. Use could query from rte_eth_dev_info_get API. Thanks. > > . >