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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5B317C433E0 for ; Fri, 29 Jan 2021 23:14:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E48C364DF5 for ; Fri, 29 Jan 2021 23:14:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232637AbhA2XOC (ORCPT ); Fri, 29 Jan 2021 18:14:02 -0500 Received: from mga12.intel.com ([192.55.52.136]:8868 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231287AbhA2XNx (ORCPT ); Fri, 29 Jan 2021 18:13:53 -0500 IronPort-SDR: z9zK3GWsdfj5rBObddgaC+JkPC0/llffQNVp9C+wsOjJTmUVJIXQYkMsgUlm47D/ONxXAvygwf /423cz/GMvmw== X-IronPort-AV: E=McAfee;i="6000,8403,9879"; a="159663693" X-IronPort-AV: E=Sophos;i="5.79,386,1602572400"; d="scan'208";a="159663693" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 15:13:12 -0800 IronPort-SDR: IP3ldZjSX8dNItA2zvtEg14fcKo1sT8oSp9Med1Xh/wWOHaEvG3yXgXnESEjNv+4I/DOVer3t7 3nxa56QtDt1A== X-IronPort-AV: E=Sophos;i="5.79,386,1602572400"; d="scan'208";a="574263502" Received: from ndatiri-mobl.amr.corp.intel.com (HELO vcostago-mobl2.amr.corp.intel.com) ([10.212.145.249]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jan 2021 15:13:12 -0800 From: Vinicius Costa Gomes To: Jakub Kicinski Cc: Vladimir Oltean , "netdev@vger.kernel.org" , "jhs@mojatatu.com" , "xiyou.wangcong@gmail.com" , "jiri@resnulli.us" , "Jose.Abreu@synopsys.com" , Po Liu , "intel-wired-lan@lists.osuosl.org" , "anthony.l.nguyen@intel.com" , "mkubecek@suse.cz" Subject: Re: [PATCH net-next v3 2/8] taprio: Add support for frame preemption offload In-Reply-To: <20210129135702.0f8cf702@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> References: <20210122224453.4161729-1-vinicius.gomes@intel.com> <20210122224453.4161729-3-vinicius.gomes@intel.com> <20210126000924.jjkjruzmh5lgrkry@skbuf> <87wnvvsayz.fsf@vcostago-mobl2.amr.corp.intel.com> <20210129135702.0f8cf702@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> Date: Fri, 29 Jan 2021 15:12:58 -0800 Message-ID: <878s8bs5fp.fsf@vcostago-mobl2.amr.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Jakub Kicinski writes: >> > First I'm interested in the means: why check for preempt == U32_MAX when >> > you determine that all traffic classes are preemptible? What if less >> > than 32 traffic classes are used by the netdev? The check will be >> > bypassed, won't it? >> >> Good catch :-) >> >> I wanted to have this (at least one express queue) handled in a >> centralized way, but perhaps this should be handled best per driver. > > Centralized is good. Much easier than reviewing N drivers to make sure > they all behave the same, and right. The issue is that it seems that not all drivers/hw have the same limitation: that at least one queue needs to be configured as express/not preemptible. That's the point I was trying to make when I suggested for the check to be done per-driver, different limitations. Cheers, -- Vinicius