From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 77A89EB64D9 for ; Thu, 6 Jul 2023 06:39:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232711AbjGFGj1 (ORCPT ); Thu, 6 Jul 2023 02:39:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55310 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232912AbjGFGj0 (ORCPT ); Thu, 6 Jul 2023 02:39:26 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F93519B; Wed, 5 Jul 2023 23:39:23 -0700 (PDT) Received: from kwepemi500006.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4QxRd64ml9ztR4R; Thu, 6 Jul 2023 14:36:26 +0800 (CST) Received: from [10.67.102.17] (10.67.102.17) by kwepemi500006.china.huawei.com (7.221.188.68) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Thu, 6 Jul 2023 14:39:19 +0800 Message-ID: <302f10de-6e4a-d665-e0f1-dee113eeb9c0@hisilicon.com> Date: Thu, 6 Jul 2023 14:39:18 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.1.0 Subject: Re: [PATCH v2 for-next] RDMA/core: Get IB width and speed from netdev Content-Language: en-US To: Leon Romanovsky CC: , , , References: <20230603063833.541682-1-huangjunxian6@hisilicon.com> <20230611174605.GG12152@unreal> <1b11b9e9-a729-0d61-52e3-6bcf132ca356@hisilicon.com> <20230628050019.GC23952@unreal> <53e8025d-803d-f6c5-b853-8352163d9a2e@hisilicon.com> <20230705071205.GH6455@unreal> From: Junxian Huang In-Reply-To: <20230705071205.GH6455@unreal> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.102.17] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemi500006.china.huawei.com (7.221.188.68) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 2023/7/5 15:12, Leon Romanovsky wrote: > On Wed, Jul 05, 2023 at 11:05:50AM +0800, Junxian Huang wrote: >> >> >> On 2023/6/28 13:00, Leon Romanovsky wrote: >>> On Mon, Jun 19, 2023 at 02:20:54PM +0800, Junxian Huang wrote: >>>> >>>> >>>> On 2023/6/12 1:46, Leon Romanovsky wrote: >>>>> On Sat, Jun 03, 2023 at 02:38:33PM +0800, Junxian Huang wrote: >>>>>> From: Haoyue Xu >>>>>> >>>>>> Previously, there was no way to query the number of lanes for a network >>>>>> card, so the same netdev_speed would result in a fixed pair of width and >>>>>> speed. As network card specifications become more diverse, such fixed >>>>>> mode is no longer suitable, so a method is needed to obtain the correct >>>>>> width and speed based on the number of lanes. >>>>> >>>>> I'm sorry but I didn't understand the problem statement. Can you please >>>>> provide an example of configuration that will give different results >>>>> before this patch and after? >>>>> >>>> >>>> I'll give examples with 20G and 200G netdevs respectively. >>>> >>>> 20G: >>>> Before this patch, regardless of the actual number of lanes, the width and >>>> speed displayed in ibv_devinfo would be always fixed: >>>> active_width: 4X >>>> active_speed: 5 Gbps >>>> After this patch, there will be different combinations of width and speed >>>> according to the number of lanes. For example, for a 20G netdev whose number >>>> of lanes is 2, the width and speed displayed in ibv_devinfo will be: >>>> active_width: 2X >>>> active_speed: 10 Gbps >>>> >>>> 200G: >>>> Before this patch, netdevs with netdev_speed more than 40G cannot get a right >>>> width and speed in ibv_devinfo. Only the default result would be displayed: >>>> active_width: 4X >>>> active_speed: 25 Gbps >>>> After this patch, taking an example with 4 lanes, the displayed results will be: >>>> active_width: 4X >>>> active_speed: 50 Gbps >>>> >>> >>> <...> >>> >>>>>> + cap_link_lanes_supported = netdev->ethtool_ops->cap_link_lanes_supported; >>>>>> rtnl_unlock(); >>>>>> >>>>>> dev_put(netdev); >>>>>> >>>>>> if (!rc && lksettings.base.speed != (u32)SPEED_UNKNOWN) { >>>>>> netdev_speed = lksettings.base.speed; >>>>>> + if (cap_link_lanes_supported && lksettings.lanes) { >>>>> >>>>> According to the documentation cap_link_lanes_supported defines if >>>>> number of lanes can be supplied by user and I would expect from >>>>> __ethtool_get_link_ksettings() to get right numbers after it was >>>>> changed. >>> >>> No, I'm saying that cap_link_lanes_supported is variable which only says >>> if number of lanes can be changed and __ethtool_get_link_ksettings() >>> will return right number of lanes every time it is called without need >>> to call to ib_get_width_and_speed() again. >>> >>> Thanks >>> >> >> These two functions have different purposes. >> >> The number of lanes is indeed obtained from __ethtool_get_link_ksettings(), >> and ib_get_width_and_speed() converts the number of lanes into ib_width and >> ib_speed, which are the output of ib_get_eth_speed(). > > Great, so why do you need to rely on cap_link_lanes_supported in ib_get_width_and_speed()? > > Thanks Ah, I see what you mean. If cap_link_lanes_supported is false, lksettings.lanes will become 0, and ib_get_width_and_speed() won't be called. Therefore, cap_link_lanes_supported is redundant. I'll fix it in v3. Thanks. Junxian