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 4C83FEB64D9 for ; Tue, 4 Jul 2023 09:38:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231859AbjGDJiX (ORCPT ); Tue, 4 Jul 2023 05:38:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232281AbjGDJiD (ORCPT ); Tue, 4 Jul 2023 05:38:03 -0400 Received: from mga03.intel.com (mga03.intel.com [134.134.136.65]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 75B332D76; Tue, 4 Jul 2023 02:36:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1688463363; x=1719999363; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=KzSG8zPwxiuEhCxKa+1sGQKJsFvciwT8AUYmTM/7rrg=; b=K8pfJC7dB+QDBB88vvoTNlk2jv7YPSAayNtoU14QXxQaaStMDMvzBPy0 9tjbBQUzgPW/5LP744ALR3y0bZxfhYlJ1FNVf9wvgE9DLFPwJkfdbtHo8 0vwHl6XIMkgc3WGOIMEmY9SzSDN0aDJ1m2tRkQmOUQ4Im0SFqx//oODVT G8PIY5aQtjHvlIrmTkiUfCsX8AUDiIu3VyHSP+UhGMir11KwzCPebXjJz jUuq40hzKJd99Kq8bx/BrnUuYd5ipKG4SpFA/ngyxBxZYIHvtExb0Nb8d O48z+nqAaJDXMm+vZ8qS+gBa+RLh7q1k3HkeP3HiRkpOkTLcJYO9S7i3n A==; X-IronPort-AV: E=McAfee;i="6600,9927,10760"; a="366564134" X-IronPort-AV: E=Sophos;i="6.01,180,1684825200"; d="scan'208";a="366564134" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2023 02:35:05 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10760"; a="696093980" X-IronPort-AV: E=Sophos;i="6.01,180,1684825200"; d="scan'208";a="696093980" Received: from naamamex-mobl.ger.corp.intel.com (HELO [10.13.12.63]) ([10.13.12.63]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Jul 2023 02:35:01 -0700 Message-ID: <6136a4bd-1818-f875-5355-547ffb3bd25b@linux.intel.com> Date: Tue, 4 Jul 2023 12:34:58 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.12.0 Subject: Re: [Intel-wired-lan] [PATCH net v2 4/6] igc: No strict mode in pure launchtime/CBS offload Content-Language: en-US To: Florian Kauer , Jesse Brandeburg , Tony Nguyen , Vinicius Costa Gomes , "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Tan Tee Min , Muhammad Husaini Zulkifli , Aravindhan Gunasekaran , Malli C Cc: netdev@vger.kernel.org, kurt@linutronix.de, intel-wired-lan@lists.osuosl.org, linux-kernel@vger.kernel.org References: <20230619100858.116286-1-florian.kauer@linutronix.de> <20230619100858.116286-5-florian.kauer@linutronix.de> From: "naamax.meir" In-Reply-To: <20230619100858.116286-5-florian.kauer@linutronix.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 6/19/2023 13:08, Florian Kauer wrote: > The flags IGC_TXQCTL_STRICT_CYCLE and IGC_TXQCTL_STRICT_END > prevent the packet transmission over slot and cycle boundaries. > This is important for taprio offload where the slots and > cycles correspond to the slots and cycles configured for the > network. > > However, the Qbv offload feature of the i225 is also used for > enabling TX launchtime / ETF offload. In that case, however, > the cycle has no meaning for the network and is only used > internally to adapt the base time register after a second has > passed. > > Enabling strict mode in this case would unneccesarily prevent > the transmission of certain packets (i.e. at the boundary of a > second) and thus interfers with the ETF qdisc that promises > transmission at a certain point in time. > > Similar to ETF, this also applies to CBS offload that also should > not be influenced by strict mode unless taprio offload would be > enabled at the same time. > > This fully reverts > commit d8f45be01dd9 ("igc: Use strict cycles for Qbv scheduling") > but its commit message only describes what was already implemented > before that commit. The difference to a plain revert of that commit > is that it now copes with the base_time = 0 case that was fixed with > commit e17090eb2494 ("igc: allow BaseTime 0 enrollment for Qbv") > > In particular, enabling strict mode leads to TX hang situations > under high traffic if taprio is applied WITHOUT taprio offload > but WITH ETF offload, e.g. as in > > sudo tc qdisc replace dev enp1s0 parent root handle 100 taprio \ > num_tc 1 \ > map 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 \ > queues 1@0 \ > base-time 0 \ > sched-entry S 01 300000 \ > flags 0x1 \ > txtime-delay 500000 \ > clockid CLOCK_TAI > sudo tc qdisc replace dev enp1s0 parent 100:1 etf \ > clockid CLOCK_TAI \ > delta 500000 \ > offload \ > skip_sock_check > > and traffic generator > > sudo trafgen -i traffic.cfg -o enp1s0 --cpp -n0 -q -t1400ns > > with traffic.cfg > > #define ETH_P_IP 0x0800 > > { > /* Ethernet Header */ > 0x30, 0x1f, 0x9a, 0xd0, 0xf0, 0x0e, # MAC Dest - adapt as needed > 0x24, 0x5e, 0xbe, 0x57, 0x2e, 0x36, # MAC Src - adapt as needed > const16(ETH_P_IP), > > /* IPv4 Header */ > 0b01000101, 0, # IPv4 version, IHL, TOS > const16(1028), # IPv4 total length (UDP length + 20 bytes (IP header)) > const16(2), # IPv4 ident > 0b01000000, 0, # IPv4 flags, fragmentation off > 64, # IPv4 TTL > 17, # Protocol UDP > csumip(14, 33), # IPv4 checksum > > /* UDP Header */ > 10, 0, 48, 1, # IP Src - adapt as needed > 10, 0, 48, 10, # IP Dest - adapt as needed > const16(5555), # UDP Src Port > const16(6666), # UDP Dest Port > const16(1008), # UDP length (UDP header 8 bytes + payload length) > csumudp(14, 34), # UDP checksum > > /* Payload */ > fill('W', 1000), > } > > and the observed message with that is for example > > igc 0000:01:00.0 enp1s0: Detected Tx Unit Hang > Tx Queue <0> > TDH > TDT > next_to_use > next_to_clean > buffer_info[next_to_clean] > time_stamp > next_to_watch <00000000245a4efb> > jiffies > desc.status <1048000> > > Fixes: d8f45be01dd9 ("igc: Use strict cycles for Qbv scheduling") > Signed-off-by: Florian Kauer > Reviewed-by: Kurt Kanzenbach > --- > drivers/net/ethernet/intel/igc/igc_tsn.c | 24 ++++++++++++++++++++++-- > 1 file changed, 22 insertions(+), 2 deletions(-) Tested-by: Naama Meir