From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinicius Costa Gomes Date: Mon, 11 Apr 2022 16:36:42 -0700 Subject: [Intel-wired-lan] [PATCH net-next v4 11/12] igc: Check incompatible configs for Frame Preemption In-Reply-To: <20210628092003.bribdjfaxwnpdt5f@skbuf> References: <20210626003314.3159402-1-vinicius.gomes@intel.com> <20210626003314.3159402-12-vinicius.gomes@intel.com> <20210628092003.bribdjfaxwnpdt5f@skbuf> Message-ID: <87wnfvchv9.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: intel-wired-lan@osuosl.org List-ID: Vladimir Oltean writes: > On Fri, Jun 25, 2021 at 05:33:13PM -0700, Vinicius Costa Gomes wrote: >> Frame Preemption and LaunchTime cannot be enabled on the same queue. >> If that situation happens, emit an error to the user, and log the >> error. >> >> Signed-off-by: Vinicius Costa Gomes >> --- > > This is a very interesting limitation, considering the fact that much of > the frame preemption validation that I did was in conjunction with > tc-etf and SO_TXTIME (send packets on 2 queues, one preemptible and one > express, and compare the TX timestamps of the express packets with their > scheduled TX times). The base-time offset between the ET and the PT > packets is varied in small increments in the order of 20 ns or so. > If this is not possible with hardware driven by igc, how do you know it > works properly? :) Good question. My tests were much less accurate than what you were doing, I was basically flooding the link with preemptable packets, and sending some number of express packets, and counting them using some debug counters on the receiving side. Cheers, -- Vinicius 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 B6266C433F5 for ; Mon, 11 Apr 2022 23:36:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233354AbiDKXi7 (ORCPT ); Mon, 11 Apr 2022 19:38:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49286 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229637AbiDKXi6 (ORCPT ); Mon, 11 Apr 2022 19:38:58 -0400 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23A88255BB for ; Mon, 11 Apr 2022 16:36:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1649720203; x=1681256203; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=NzZt4IBwnWx6owLRJPhA+huTplPrlQZy3WYXyAwpsSA=; b=YCJm8N1Cqk4YbrNzpdHtR57cxzX7tgHCQmDrx3QmfrhZVGBRGgCqYMNq OcpLNSApQoiDq/XS/y13lWcEoJB6fOop6ck3go20McZu3cKLIL44xeTE2 wNRPwqEyzs1OHxwiGBzyBtQMUBKrPkhpV5ud7acP6JO+qAj30b4MqbZJJ uQxlq1qK+I37ha8ijUoxvPtWhOZKulJ3Y6kZ5FUPefymiE+DhqrZiuHxS q0HC4HWjr0P5WvS5Pzize2OrCKd3QGw8OZy43IabGa3ydZjc4wihviKhj aNaA3hsFjbhKZEqlBMCcLj2Lj9PreB2y8ZkWnRZXYpTMEjztiiKqTubiR g==; X-IronPort-AV: E=McAfee;i="6400,9594,10314"; a="249521315" X-IronPort-AV: E=Sophos;i="5.90,252,1643702400"; d="scan'208";a="249521315" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Apr 2022 16:36:42 -0700 X-IronPort-AV: E=Sophos;i="5.90,252,1643702400"; d="scan'208";a="572469523" Received: from vcostago-mobl3.jf.intel.com (HELO vcostago-mobl3) ([10.24.14.61]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 11 Apr 2022 16:36:42 -0700 From: Vinicius Costa Gomes To: Vladimir Oltean Cc: "netdev@vger.kernel.org" , "jhs@mojatatu.com" , "xiyou.wangcong@gmail.com" , "jiri@resnulli.us" , "kuba@kernel.org" , Po Liu , "intel-wired-lan@lists.osuosl.org" , "anthony.l.nguyen@intel.com" , "mkubecek@suse.cz" Subject: Re: [PATCH net-next v4 11/12] igc: Check incompatible configs for Frame Preemption In-Reply-To: <20210628092003.bribdjfaxwnpdt5f@skbuf> References: <20210626003314.3159402-1-vinicius.gomes@intel.com> <20210626003314.3159402-12-vinicius.gomes@intel.com> <20210628092003.bribdjfaxwnpdt5f@skbuf> Date: Mon, 11 Apr 2022 16:36:42 -0700 Message-ID: <87wnfvchv9.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Vladimir Oltean writes: > On Fri, Jun 25, 2021 at 05:33:13PM -0700, Vinicius Costa Gomes wrote: >> Frame Preemption and LaunchTime cannot be enabled on the same queue. >> If that situation happens, emit an error to the user, and log the >> error. >> >> Signed-off-by: Vinicius Costa Gomes >> --- > > This is a very interesting limitation, considering the fact that much of > the frame preemption validation that I did was in conjunction with > tc-etf and SO_TXTIME (send packets on 2 queues, one preemptible and one > express, and compare the TX timestamps of the express packets with their > scheduled TX times). The base-time offset between the ET and the PT > packets is varied in small increments in the order of 20 ns or so. > If this is not possible with hardware driven by igc, how do you know it > works properly? :) Good question. My tests were much less accurate than what you were doing, I was basically flooding the link with preemptable packets, and sending some number of express packets, and counting them using some debug counters on the receiving side. Cheers, -- Vinicius