From patchwork Sun Jul 7 12:53:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Abdul Rahim, Faizal" X-Patchwork-Id: 13726007 X-Patchwork-Delegate: kuba@kernel.org Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E7102263A; Sun, 7 Jul 2024 12:55:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720356950; cv=none; b=Opyk3YY14iROM6cyHbZtFlgC18/ECO0BAH9eP6H3QVrrqBlXZPpZ5pFrv5XGyeY1crf3bnF1brGvihLC/BckG6Gtn8gxFRKSJp6BPrYre+Kyvb4yvTNOM8EqsCyUbaSmAwDPybCLEzxRUuUiKpjx/ZEgyIqo2mu11hs/BSgchdc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720356950; c=relaxed/simple; bh=tQF6ozfBKP+jPtiv0rM/lmlMPzLKQsttHfHaT183vZk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=NKn4DErc+b8QYhawDxqwXdrMVH4jOtxtLiWbE2DpFZiA+ztL4axQbI37+zG+baYSxsg3tAMm4peM+qC5ynfLu6NBtzBjtEX8BYGmDsKk/21q0/t29IVFrI+W0tJGrI74bzo8po96KFJb48aKBn7ME58T3BycgExf+17I7iYllBg= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=ADJpJqHH; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="ADJpJqHH" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1720356949; x=1751892949; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=tQF6ozfBKP+jPtiv0rM/lmlMPzLKQsttHfHaT183vZk=; b=ADJpJqHHzWrqyBrLNHayrPK2py/7nxSovTv+mRobJuJNMk/pCduvyOTB dpTZ0WNFSyTsNpxS0qG6Lme2wUs8Bs30cHdBsb8BOCKK6XOaX4X4i1Uv6 fZnD8NxIw4qAz1zuGUVUL7RySsszrceW1mCcBegcw284JNV0eENUwjhva HgO8cdQpaieHSdTU8dHEhOHf5KAEqqMWqWwCrfrhft+yjvwov/FHJC4Zs sTaQF/EYGVfq41XVBcZNXpz8W3879A+ZFeoSvIwD9eoWsmKZuiBjUFRGQ ko6e62fOQdknlmPp5Q3CCwwxw5pqlu5I+hpewGwjdrCyRykfe3Dplx0HY Q==; X-CSE-ConnectionGUID: 4NAQ/D6OQBqHaKAX1zhfew== X-CSE-MsgGUID: bZT4CVcqQXixi0L0Y7bMwg== X-IronPort-AV: E=McAfee;i="6700,10204,11125"; a="17673459" X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="17673459" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:48 -0700 X-CSE-ConnectionGUID: 2S7CYKyxT3+zy3DqW2yehA== X-CSE-MsgGUID: 4SKpKOtqTeiGdJIs2bchdw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="47029662" Received: from linux.intel.com ([10.54.29.200]) by fmviesa006.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:46 -0700 Received: from mohdfai2-iLBPG12-1.png.intel.com (mohdfai2-iLBPG12-1.png.intel.com [10.88.227.73]) by linux.intel.com (Postfix) with ESMTP id 06BA920738C7; Sun, 7 Jul 2024 05:55:42 -0700 (PDT) From: Faizal Rahim To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jesse Brandeburg , Tony Nguyen , Vinicius Costa Gomes , Simon Horman , Richard Cochran , Paul Menzel , Sasha Neftin Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Faizal Rahim Subject: [PATCH iwl-net v2 1/3] igc: Fix qbv_config_change_errors logics Date: Sun, 7 Jul 2024 08:53:16 -0400 Message-Id: <20240707125318.3425097-2-faizal.abdul.rahim@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> References: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org When user issues these cmds: 1. Either a) or b) a) mqprio with hardware offload disabled b) taprio with txtime-assist feature enabled 2. etf 3. tc qdisc delete 4. taprio with base time in the past At step 4, qbv_config_change_errors wrongly increased by 1. Excerpt from IEEE 802.1Q-2018 8.6.9.3.1: "If AdminBaseTime specifies a time in the past, and the current schedule is running, then: Increment ConfigChangeError counter" qbv_config_change_errors should only increase if base time is in the past and no taprio is active. In user perspective, taprio was not active when first triggered at step 4. However, i225/6 reuses qbv for etf, so qbv is enabled with a dummy schedule at step 2 where it enters igc_tsn_enable_offload() and qbv_count got incremented to 1. At step 4, it enters igc_tsn_enable_offload() again, qbv_count is incremented to 2. Because taprio is running, tc_setup_type is TC_SETUP_QDISC_ETF and qbv_count > 1, qbv_config_change_errors value got incremented. This issue happens due to reliance on qbv_count field where a non-zero value indicates that taprio is running. But qbv_count increases regardless if taprio is triggered by user or by other tsn feature. It does not align with qbv_config_change_errors expectation where it is only concerned with taprio triggered by user. Fixing this by relocating the qbv_config_change_errors logic to igc_save_qbv_schedule(), eliminating reliance on qbv_count and its inaccuracies from i225/6's multiple uses of qbv feature for other TSN features. The new function created: igc_tsn_is_taprio_activated_by_user() uses taprio_offload_enable field to indicate that the current running taprio was triggered by user, instead of triggered by non-qbv feature like etf. Fixes: ae4fe4698300 ("igc: Add qbv_config_change_errors counter") Signed-off-by: Faizal Rahim Reviewed-by: Simon Horman Acked-by: Vinicius Costa Gomes Tested-by: Mor Bar-Gabay --- drivers/net/ethernet/intel/igc/igc_main.c | 8 ++++++-- drivers/net/ethernet/intel/igc/igc_tsn.c | 16 ++++++++-------- drivers/net/ethernet/intel/igc/igc_tsn.h | 1 + 3 files changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c index 305e05294a26..0f8a5ad940ec 100644 --- a/drivers/net/ethernet/intel/igc/igc_main.c +++ b/drivers/net/ethernet/intel/igc/igc_main.c @@ -6334,12 +6334,16 @@ static int igc_save_qbv_schedule(struct igc_adapter *adapter, if (!validate_schedule(adapter, qopt)) return -EINVAL; + igc_ptp_read(adapter, &now); + + if (igc_tsn_is_taprio_activated_by_user(adapter) && + is_base_time_past(qopt->base_time, &now)) + adapter->qbv_config_change_errors++; + adapter->cycle_time = qopt->cycle_time; adapter->base_time = qopt->base_time; adapter->taprio_offload_enable = true; - igc_ptp_read(adapter, &now); - for (n = 0; n < qopt->num_entries; n++) { struct tc_taprio_sched_entry *e = &qopt->entries[n]; diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c index 22cefb1eeedf..f6eaa288926e 100644 --- a/drivers/net/ethernet/intel/igc/igc_tsn.c +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c @@ -78,6 +78,14 @@ void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter) wr32(IGC_GTXOFFSET, txoffset); } +bool igc_tsn_is_taprio_activated_by_user(struct igc_adapter *adapter) +{ + struct igc_hw *hw = &adapter->hw; + + return (rd32(IGC_BASET_H) || rd32(IGC_BASET_L)) && + adapter->taprio_offload_enable; +} + /* Returns the TSN specific registers to their default values after * the adapter is reset. */ @@ -262,14 +270,6 @@ static int igc_tsn_enable_offload(struct igc_adapter *adapter) s64 n = div64_s64(ktime_sub_ns(systim, base_time), cycle); base_time = ktime_add_ns(base_time, (n + 1) * cycle); - - /* Increase the counter if scheduling into the past while - * Gate Control List (GCL) is running. - */ - if ((rd32(IGC_BASET_H) || rd32(IGC_BASET_L)) && - (adapter->tc_setup_type == TC_SETUP_QDISC_TAPRIO) && - (adapter->qbv_count > 1)) - adapter->qbv_config_change_errors++; } else { if (igc_is_device_id_i226(hw)) { ktime_t adjust_time, expires_time; diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.h b/drivers/net/ethernet/intel/igc/igc_tsn.h index b53e6af560b7..98ec845a86bf 100644 --- a/drivers/net/ethernet/intel/igc/igc_tsn.h +++ b/drivers/net/ethernet/intel/igc/igc_tsn.h @@ -7,5 +7,6 @@ int igc_tsn_offload_apply(struct igc_adapter *adapter); int igc_tsn_reset(struct igc_adapter *adapter); void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter); +bool igc_tsn_is_taprio_activated_by_user(struct igc_adapter *adapter); #endif /* _IGC_BASE_H */ From patchwork Sun Jul 7 12:53:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Abdul Rahim, Faizal" X-Patchwork-Id: 13726008 X-Patchwork-Delegate: kuba@kernel.org Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DB34E29405; 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X-CSE-ConnectionGUID: 1/INWc1STOCWP6VxUBm8Yw== X-CSE-MsgGUID: v/fHZuQSSc69sYkVhqMekQ== X-IronPort-AV: E=McAfee;i="6700,10204,11125"; a="21337371" X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="21337371" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa107.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:52 -0700 X-CSE-ConnectionGUID: qPlxzrs1R821m7XL6DuSKQ== X-CSE-MsgGUID: gVXbjNsnQqCjscY3lb0/SQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="47359038" Received: from linux.intel.com ([10.54.29.200]) by orviesa009.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:51 -0700 Received: from mohdfai2-iLBPG12-1.png.intel.com (mohdfai2-iLBPG12-1.png.intel.com [10.88.227.73]) by linux.intel.com (Postfix) with ESMTP id 1517E20738CF; Sun, 7 Jul 2024 05:55:46 -0700 (PDT) From: Faizal Rahim To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jesse Brandeburg , Tony Nguyen , Vinicius Costa Gomes , Simon Horman , Richard Cochran , Paul Menzel , Sasha Neftin Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Faizal Rahim Subject: [PATCH iwl-net v2 2/3] igc: Fix reset adapter logics when tx mode change Date: Sun, 7 Jul 2024 08:53:17 -0400 Message-Id: <20240707125318.3425097-3-faizal.abdul.rahim@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> References: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Following the "igc: Fix TX Hang issue when QBV Gate is close" changes, remaining issues with the reset adapter logic in igc_tsn_offload_apply() have been observed: 1. The reset adapter logics for i225 and i226 differ, although they should be the same according to the guidelines in I225/6 HW Design Section 7.5.2.1 on software initialization during tx mode changes. 2. The i225 resets adapter every time, even though tx mode doesn't change. This occurs solely based on the condition igc_is_device_id_i225() when calling schedule_work(). 3. i226 doesn't reset adapter for tsn->legacy tx mode changes. It only resets adapter for legacy->tsn tx mode transitions. 4. qbv_count introduced in the patch is actually not needed; in this context, a non-zero value of qbv_count is used to indicate if tx mode was unconditionally set to tsn in igc_tsn_enable_offload(). This could be replaced by checking the existing register IGC_TQAVCTRL_TRANSMIT_MODE_TSN bit. This patch resolves all issues and enters schedule_work() to reset the adapter only when changing tx mode. It also removes reliance on qbv_count. qbv_count field will be removed in a future patch. Test ran: 1. Verify reset adapter behaviour in i225/6: a) Enrol a new GCL Reset adapter observed (tx mode change legacy->tsn) b) Enrol a new GCL without deleting qdisc No reset adapter observed (tx mode remain tsn->tsn) c) Delete qdisc Reset adapter observed (tx mode change tsn->legacy) 2. Tested scenario from "igc: Fix TX Hang issue when QBV Gate is closed" to confirm it remains resolved. Fixes: 175c241288c0 ("igc: Fix TX Hang issue when QBV Gate is closed") Signed-off-by: Faizal Rahim Reviewed-by: Simon Horman Acked-by: Vinicius Costa Gomes Acked-by: Vinicius Costa Gomes Tested-by: Mor Bar-Gabay --- drivers/net/ethernet/intel/igc/igc_tsn.c | 23 ++++++++++++++++++++--- 1 file changed, 20 insertions(+), 3 deletions(-) diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c index f6eaa288926e..9fafe275f30f 100644 --- a/drivers/net/ethernet/intel/igc/igc_tsn.c +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c @@ -49,6 +49,13 @@ static unsigned int igc_tsn_new_flags(struct igc_adapter *adapter) return new_flags; } +static bool igc_tsn_is_tx_mode_in_tsn(struct igc_adapter *adapter) +{ + struct igc_hw *hw = &adapter->hw; + + return !!(rd32(IGC_TQAVCTRL) & IGC_TQAVCTRL_TRANSMIT_MODE_TSN); +} + void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter) { struct igc_hw *hw = &adapter->hw; @@ -331,15 +338,25 @@ int igc_tsn_reset(struct igc_adapter *adapter) return err; } +static bool igc_tsn_will_tx_mode_change(struct igc_adapter *adapter) +{ + bool any_tsn_enabled = (bool)(igc_tsn_new_flags(adapter) & + IGC_FLAG_TSN_ANY_ENABLED); + + return (any_tsn_enabled && !igc_tsn_is_tx_mode_in_tsn(adapter)) || + (!any_tsn_enabled && igc_tsn_is_tx_mode_in_tsn(adapter)); +} + int igc_tsn_offload_apply(struct igc_adapter *adapter) { struct igc_hw *hw = &adapter->hw; - /* Per I225/6 HW Design Section 7.5.2.1, transmit mode - * cannot be changed dynamically. Require reset the adapter. + /* Per I225/6 HW Design Section 7.5.2.1 guideline, if tx mode change + * from legacy->tsn or tsn->legacy, then reset adapter is needed. */ if (netif_running(adapter->netdev) && - (igc_is_device_id_i225(hw) || !adapter->qbv_count)) { + (igc_is_device_id_i225(hw) || igc_is_device_id_i226(hw)) && + igc_tsn_will_tx_mode_change(adapter)) { schedule_work(&adapter->reset_task); return 0; } From patchwork Sun Jul 7 12:53:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Abdul Rahim, Faizal" X-Patchwork-Id: 13726009 X-Patchwork-Delegate: kuba@kernel.org Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 95BC037143; Sun, 7 Jul 2024 12:55:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720356957; cv=none; b=cqahdpxMbl7WmBn2sWXy7MlbPI0bP4D3J8m9nWxfrbkkkgpzxfAHWsx2OhVv7Tv/nZ6J4jIs/O9H9o+IimGVV7zWSDtI0O1lWvAEgFiqeZHvSgiT0HEoPncAia9PjoaoDGUL3HgRxVcRcRqIwlO0AKJq9sjx1dqcd76nhnxZdT8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720356957; c=relaxed/simple; bh=yq9fdn79P/7uXLeqkaqvokXNESEJw6LEGZiE5haj0rk=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=H4M4StYh3Ur3BXQUjTXVlvFC3QXNSbjXkmFC6e+F6ItCBKzQ8m+KzSpq99U5uyZ4RFKzwhYuShfr5StXN8l351xIFtwUOHyX5YOM0+Tk2AqddgGqzfqrlfBQO9nyLSYNZsBSoaG7frYmskeyrEfnhKPa6RslqbDMMmlQToJ20l4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=none smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=hwA0rndF; arc=none smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="hwA0rndF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1720356956; x=1751892956; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=yq9fdn79P/7uXLeqkaqvokXNESEJw6LEGZiE5haj0rk=; b=hwA0rndFL9qfbsFDksMiZ9cLIUW95MBJqaXu6vX5rTz03hrpYBwfeg4a bR75vWbo8a6nM32+foCXYXIWbfa7BZLiosw2ARKNDEyLgrekVt+pGDwab gglGxl4mO16WJUdZmYseF1ZAav2Zv52wqTCJwugugmlV2ofo7HAaR5qZc nXnsLlx5gqk6LSoP1voXioI2h5xYtmjGG1r6ETwQKPPV1Wc78gBGnmObp HfWfA0ENt7xmq5cezs0tCtGOv3t10dX40w0l5lSM4B6RtUrJlYX23Bflb DNA4ZdUzZUyn03N8Q6vyplsZBptDFYGHuUkqNRqW+N3KOd9pVUo+J3pi5 Q==; X-CSE-ConnectionGUID: /VNgHnndTAGdutYeo+UIEg== X-CSE-MsgGUID: Kgn66ITeTSe7hECb71koOA== X-IronPort-AV: E=McAfee;i="6700,10204,11125"; a="17673469" X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="17673469" Received: from fmviesa006.fm.intel.com ([10.60.135.146]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:55 -0700 X-CSE-ConnectionGUID: xPp/wiFMS6+0YZ9L/LZb1w== X-CSE-MsgGUID: rdCxZ3vISw62k2inJpqk0w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.09,190,1716274800"; d="scan'208";a="47029673" Received: from linux.intel.com ([10.54.29.200]) by fmviesa006.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Jul 2024 05:55:55 -0700 Received: from mohdfai2-iLBPG12-1.png.intel.com (mohdfai2-iLBPG12-1.png.intel.com [10.88.227.73]) by linux.intel.com (Postfix) with ESMTP id E556420738C7; Sun, 7 Jul 2024 05:55:50 -0700 (PDT) From: Faizal Rahim To: "David S . Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jesse Brandeburg , Tony Nguyen , Vinicius Costa Gomes , Simon Horman , Richard Cochran , Paul Menzel , Sasha Neftin Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Faizal Rahim Subject: [PATCH iwl-net v2 3/3] igc: Fix qbv tx latency by setting gtxoffset Date: Sun, 7 Jul 2024 08:53:18 -0400 Message-Id: <20240707125318.3425097-4-faizal.abdul.rahim@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> References: <20240707125318.3425097-1-faizal.abdul.rahim@linux.intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org A large tx latency issue was discovered during testing when only QBV was enabled. The issue occurs because gtxoffset was not set when QBV is active, it was only set when launch time is active. The patch "igc: Correct the launchtime offset" only sets gtxoffset when the launchtime_enable field is set by the user. Enabling launchtime_enable ultimately sets the register IGC_TXQCTL_QUEUE_MODE_LAUNCHT (referred to as LaunchT in the SW user manual). Section 7.5.2.6 of the IGC i225/6 SW User Manual Rev 1.2.4 states: "The latency between transmission scheduling (launch time) and the time the packet is transmitted to the network is listed in Table 7-61." However, the patch misinterprets the phrase "launch time" in that section by assuming it specifically refers to the LaunchT register, whereas it actually denotes the generic term for when a packet is released from the internal buffer to the MAC transmit logic. This launch time, as per that section, also implicitly refers to the QBV gate open time, where a packet waits in the buffer for the QBV gate to open. Therefore, latency applies whenever QBV is in use. TSN features such as QBU and QAV reuse QBV, making the latency universal to TSN features. Discussed with i226 HW owner (Shalev, Avi) and we were in agreement that the term "launch time" used in Section 7.5.2.6 is not clear and can be easily misinterpreted. Avi will update this section to: "When TQAVCTRL.TRANSMIT_MODE = TSN, the latency between transmission scheduling and the time the packet is transmitted to the network is listed in Table 7-61." Fix this issue by using igc_tsn_is_tx_mode_in_tsn() as a condition to write to gtxoffset, aligning with the newly updated SW User Manual. Tested: 1. Enrol taprio on talker board base-time 0 cycle-time 1000000 flags 0x2 index 0 cmd S gatemask 0x1 interval1 index 0 cmd S gatemask 0x1 interval2 Note: interval1 = interval for a 64 bytes packet to go through interval2 = cycle-time - interval1 2. Take tcpdump on listener board 3. Use udp tai app on talker to send packets to listener 4. Check the timestamp on listener via wireshark Test Result: 100 Mbps: 113 ~193 ns 1000 Mbps: 52 ~ 84 ns 2500 Mbps: 95 ~ 223 ns Note that the test result is similar to the patch "igc: Correct the launchtime offset". Fixes: 790835fcc0cb ("igc: Correct the launchtime offset") Signed-off-by: Faizal Rahim Reviewed-by: Simon Horman Acked-by: Vinicius Costa Gomes Tested-by: Mor Bar-Gabay --- drivers/net/ethernet/intel/igc/igc_tsn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/ethernet/intel/igc/igc_tsn.c b/drivers/net/ethernet/intel/igc/igc_tsn.c index 9fafe275f30f..efe13a9350ca 100644 --- a/drivers/net/ethernet/intel/igc/igc_tsn.c +++ b/drivers/net/ethernet/intel/igc/igc_tsn.c @@ -61,7 +61,7 @@ void igc_tsn_adjust_txtime_offset(struct igc_adapter *adapter) struct igc_hw *hw = &adapter->hw; u16 txoffset; - if (!is_any_launchtime(adapter)) + if (!igc_tsn_is_tx_mode_in_tsn(adapter)) return; switch (adapter->link_speed) {