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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 A38F6C04AB6 for ; Tue, 28 May 2019 17:46:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 84F442173B for ; Tue, 28 May 2019 17:46:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727382AbfE1Rq6 (ORCPT ); Tue, 28 May 2019 13:46:58 -0400 Received: from mga12.intel.com ([192.55.52.136]:35226 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726452AbfE1Rq6 (ORCPT ); Tue, 28 May 2019 13:46:58 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga106.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 28 May 2019 10:46:57 -0700 X-ExtLoop1: 1 Received: from vpatel-desk.jf.intel.com (HELO localhost.localdomain) ([10.7.159.52]) by orsmga002.jf.intel.com with ESMTP; 28 May 2019 10:46:57 -0700 From: Vedang Patel To: netdev@vger.kernel.org Cc: jeffrey.t.kirsher@intel.com, davem@davemloft.net, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, intel-wired-lan@lists.osuosl.org, vinicius.gomes@intel.com, l@dorileo.org, Vedang Patel Subject: [PATCH net-next v1 0/7] net/sched: Add txtime assist support for taprio Date: Tue, 28 May 2019 10:46:41 -0700 Message-Id: <1559065608-27888-1-git-send-email-vedang.patel@intel.com> X-Mailer: git-send-email 2.7.3 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently, we are seeing packets being transmitted outside their timeslices. We can confirm that the packets are being dequeued at the right time. So, the delay is induced after the packet is dequeued, because taprio, without any offloading, has no control of when a packet is actually transmitted. In order to solve this, we are making use of the txtime feature provided by ETF qdisc. Hardware offloading needs to be supported by the ETF qdisc in order to take advantage of this feature. The taprio qdisc will assign txtime (in skb->tstamp) for all the packets which do not have the txtime allocated via the SO_TXTIME socket option. For the packets which already have SO_TXTIME set, taprio will validate whether the packet will be transmitted in the correct interval. In order to support this, the following parameters have been added: - offload (taprio): This is added in order to support different offloading modes which will be added in the future. - txtime-delay (taprio): this is the time the packet takes to traverse through the kernel to adapter card. - skip_sock_check (etf): etf qdisc currently drops any packet which does not have the SO_TXTIME socket option set. This check can be skipped by specifying this option. Following is an example configuration: $ tc qdisc replace dev $IFACE 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@0 1@0 \\ base-time $BASE_TIME \\ sched-entry S 01 300000 \\ sched-entry S 02 300000 \\ sched-entry S 04 400000 \\ offload 2 \\ txtime-delay 40000 \\ clockid CLOCK_TAI $ tc qdisc replace dev $IFACE parent 100:1 etf \\ offload delta 200000 clockid CLOCK_TAI skip_sock_check Here, the "offload" parameter is indicating that the TXTIME_OFFLOAD mode is enabled. Also, that all the traffic classes have been assigned the same queue. This is to prevent the traffic classes in the lower priority queues from getting starved. Note that this configuration is specific to the i210 ethernet card. Other network cards where the hardware queues are given the same priority, might be able to utilize more than one queue. Following are some of the other highlights of the series: - Fix a bug where hardware timestamping and SO_TXTIME options cannot be used together. (Patch 1) - Introduce hardware offloading. This patch introduces offload parameter which can be used to enable the txtime offload mode. It will also support enabling full offload when the support is available in drivers. (Patch 3) - Make TxTime assist mode work with TCP packets. (Patch 6 & 7) The following changes are recommended to be done in order to get the best performance from taprio in this mode: # ip link set dev enp1s0 mtu 1514 # ethtool -K eth0 gso off # ethtool -K eth0 tso off # ethtool --set-eee eth0 eee off Thanks, Vedang Patel Vedang Patel (6): igb: clear out tstamp after sending the packet. etf: Add skip_sock_check taprio: calculate cycle_time when schedule is installed taprio: Add support for txtime offload mode. taprio: make clock reference conversions easier taprio: Adjust timestamps for TCP packets. Vinicius Costa Gomes (1): taprio: Add the skeleton to enable hardware offloading drivers/net/ethernet/intel/igb/igb_main.c | 1 + include/uapi/linux/pkt_sched.h | 6 + net/sched/sch_etf.c | 10 + net/sched/sch_taprio.c | 548 ++++++++++++++++++++-- 4 files changed, 532 insertions(+), 33 deletions(-) -- 2.17.0