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 9CA79C433F5 for ; Fri, 30 Sep 2022 02:18:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229606AbiI3CST (ORCPT ); Thu, 29 Sep 2022 22:18:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39876 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229479AbiI3CSS (ORCPT ); Thu, 29 Sep 2022 22:18:18 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BB9391F11C3; Thu, 29 Sep 2022 19:18:17 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4C3516221B; Fri, 30 Sep 2022 02:18:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BD49C433C1; Fri, 30 Sep 2022 02:18:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1664504296; bh=1w5YrR1fb+EjiLPc63z7JGanZy2bUC82YznToesWRbU=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=kUpDrwthAV3nnMgpTki7GLzVNhxX6EFqJZPl72eZJ5S1vnjrkHQTOINXcGDYUBkwz 44CIdWeSi8VLMia29APU2oXVUMfOSIG4VtaSKDKFa64LCJ1lTh9LYSNZqxbClLgvfD mtrvY5eE4kjjUk4c4xXQEbRGDm6+Bjc55BecOP8Od5nlndFrgu4d2NOoesLIiRR+fi qnFc5sud6IJe7GiKNzLesmcXNPVFYRHr17pN1SY/lF3c5H+Kg0a7vxWMqoD5oSu0+E 6lh7Ftzay3CVpAxctjenwooHC1DN/q6zIpyJl1TrdKPfGV42HIm69CcMHWvwXaqxBc rqF7iNMI7NtWQ== Date: Thu, 29 Sep 2022 19:18:15 -0700 From: Jakub Kicinski To: jianghaoran Cc: vinicius.gomes@intel.com, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] taprio: Set the value of picos_per_byte before fill sched_entry Message-ID: <20220929191815.51362581@kernel.org> In-Reply-To: <20220928065830.1544954-1-jianghaoran@kylinos.cn> References: <20220928065830.1544954-1-jianghaoran@kylinos.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, 28 Sep 2022 14:58:30 +0800 jianghaoran wrote: > If the value of picos_per_byte is set after fill sched_entry, > as a result, the min_duration calculated by length_to_duration is 0, > and the validity of the input interval cannot be judged, > too small intervals couldn't allow any packet to be transmitted. Meaning an invalid configuration is accepted but no packets can ever be transmitted? Could you make the user-visible issue clearer? > It will appear like commit b5b73b26b3ca ("taprio: > Fix allowing too small intervals") described problem. > Here is a further modification of this problem. > > example: Here as well it seems worthwhile to mention what this is an example of. e.g. "example configuration which will not be able to transmit packets" > tc qdisc replace dev enp5s0f0 parent root handle 100 taprio \ > num_tc 3 \ > map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \ > queues 1@0 1@1 2@2 \ > base-time 1528743495910289987 \ > sched-entry S 01 9 \ > sched-entry S 02 9 \ > sched-entry S 04 9 \ > clockid CLOCK_TAI Please add a Fixes tag pointing to the first commit where the issue was present, and CC Vladimir Oltean on the next version.