From patchwork Thu Mar 12 18:10:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Abhishek Pandit-Subedi X-Patchwork-Id: 11435167 X-Patchwork-Delegate: marcel@holtmann.org Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9B4BE913 for ; Thu, 12 Mar 2020 18:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 683242072F for ; Thu, 12 Mar 2020 18:11:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="QoAb6gFK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726683AbgCLSLF (ORCPT ); Thu, 12 Mar 2020 14:11:05 -0400 Received: from mail-pj1-f65.google.com ([209.85.216.65]:54833 "EHLO mail-pj1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726650AbgCLSLE (ORCPT ); Thu, 12 Mar 2020 14:11:04 -0400 Received: by mail-pj1-f65.google.com with SMTP id np16so2869370pjb.4 for ; Thu, 12 Mar 2020 11:11:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=1jkZ7AJWeJX31pPItMtQ3M7DJKtphTFHpNhNX7Qly0U=; b=QoAb6gFKX7EfE1bIK+nwkeGcKII1LO23g2lG+2k9ljWhdBxBLx+6Krl+oiCa7RY6o0 R3Bbn1pcxNUThhpZQb/I32tuTg7DwkutwXkw3C4aEAeYT1JyEpULlM0IvYXniJNOt0SM BiaSTyTiDsmdVoKDEZXNdp9xJMQn9nre+Smuo= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=1jkZ7AJWeJX31pPItMtQ3M7DJKtphTFHpNhNX7Qly0U=; b=PsGp7aNUejiWKnGuKQJnzERMmiJhYdVx/tpSIBwZLxv5iBieHgkFYKS/vG1G8mDTfw 4RsnDpG9lJa8+wJhNlZLT7MQeIwFS+bd0RATyRBmo0BZWn59CEslVjzB+M3h1hUKTMpt t7V2bjyFRmP6NC99YhIPQX8U8UKPt/8In3MWpAAyjFWbaeWeZT4rXAzFOkqIbtYCa2/i WLsbbStP9290+aidaz6scUt4m/xogkYnIjAv076vO41raj1hpcpmfNs1nywTh4tFy/pl sPiaxleyp5oMghu5hc2YA+j3InHCQtUIWN7+ey7REF4fUjiUZ8UbaThbOufsvBZQNtD/ jrFQ== X-Gm-Message-State: ANhLgQ0y+qjbWdfSYekJQK0b/37PO6AnUFJmdZaZ+RVq7jOMrYzKWPXZ XoLJDY/LlG5zYR8oK1CN/XJdiQ== X-Google-Smtp-Source: ADFU+vsw3NahFCEBMGteIDtAocT6JndFQtFXaZTMSfXyJ7YszBfVl6Cp8D1TwzxJuXr/PNcj+vWU4g== X-Received: by 2002:a17:902:ba83:: with SMTP id k3mr8898506pls.26.1584036662845; Thu, 12 Mar 2020 11:11:02 -0700 (PDT) Received: from apsdesk.mtv.corp.google.com ([2620:15c:202:1:e09a:8d06:a338:aafb]) by smtp.gmail.com with ESMTPSA id b18sm56787876pfd.63.2020.03.12.11.11.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2020 11:11:02 -0700 (PDT) From: Abhishek Pandit-Subedi To: marcel@holtmann.org, linux-bluetooth@vger.kernel.org Cc: chromeos-bluetooth-upstreaming@chromium.org, Abhishek Pandit-Subedi , "David S. Miller" , Johan Hedberg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jakub Kicinski Subject: [PATCH 1/1] Bluetooth: Prioritize SCO traffic on slow interfaces Date: Thu, 12 Mar 2020 11:10:55 -0700 Message-Id: <20200312111036.1.I17e2220fd0c0822c76a15ef89b882fb4cfe3fe89@changeid> X-Mailer: git-send-email 2.25.1.481.gfbce0eb801-goog In-Reply-To: <20200312181055.94038-1-abhishekpandit@chromium.org> References: <20200312181055.94038-1-abhishekpandit@chromium.org> MIME-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org When scheduling TX packets, send all SCO/eSCO packets first and then send only 1 ACL/LE packet in a loop while checking that there are no SCO packets pending. This is done to make sure that we can meet SCO deadlines on slow interfaces like UART. If we were to queue up multiple ACL packets without checking for a SCO packet, we might miss the SCO timing. For example: The time it takes to send a maximum size ACL packet (1024 bytes): t = 10/8 * 1024 bytes * 8 bits/byte * 1 packet / baudrate where 10/8 is uart overhead due to start/stop bits per byte Replace t = 3.75ms (SCO deadline), which gives us a baudrate of 2730666 and is pretty close to a common baudrate of 3000000 used for BT. At this baudrate, if we sent two 1024 byte ACL packets, we would miss the 3.75ms timing window. Signed-off-by: Abhishek Pandit-Subedi --- include/net/bluetooth/hci_core.h | 1 + net/bluetooth/hci_core.c | 91 +++++++++++++++++++++++++------- 2 files changed, 73 insertions(+), 19 deletions(-) diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h index d4e28773d378..f636c89f1fe1 100644 --- a/include/net/bluetooth/hci_core.h +++ b/include/net/bluetooth/hci_core.h @@ -315,6 +315,7 @@ struct hci_dev { __u8 ssp_debug_mode; __u8 hw_error_code; __u32 clock; + __u8 sched_limit; __u16 devid_source; __u16 devid_vendor; diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index dbd2ad3a26ed..00a72265cd96 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -4239,18 +4239,32 @@ static void __check_timeout(struct hci_dev *hdev, unsigned int cnt) } } -static void hci_sched_acl_pkt(struct hci_dev *hdev) +/* Limit packets in flight when SCO/eSCO links are active. */ +static bool hci_sched_limit(struct hci_dev *hdev) +{ + return hdev->sched_limit && hci_conn_num(hdev, SCO_LINK); +} + +static bool hci_sched_acl_pkt(struct hci_dev *hdev) { unsigned int cnt = hdev->acl_cnt; struct hci_chan *chan; struct sk_buff *skb; int quote; + bool sched_limit = hci_sched_limit(hdev); + bool resched = false; __check_timeout(hdev, cnt); while (hdev->acl_cnt && (chan = hci_chan_sent(hdev, ACL_LINK, "e))) { u32 priority = (skb_peek(&chan->data_q))->priority; + + if (sched_limit && quote > 0) { + resched = true; + quote = 1; + } + while (quote-- && (skb = skb_peek(&chan->data_q))) { BT_DBG("chan %p skb %p len %d priority %u", chan, skb, skb->len, skb->priority); @@ -4271,19 +4285,26 @@ static void hci_sched_acl_pkt(struct hci_dev *hdev) chan->sent++; chan->conn->sent++; } + + if (resched && cnt != hdev->acl_cnt) + break; } - if (cnt != hdev->acl_cnt) + if (hdev->acl_cnt == 0 && cnt != hdev->acl_cnt) hci_prio_recalculate(hdev, ACL_LINK); + + return resched; } -static void hci_sched_acl_blk(struct hci_dev *hdev) +static bool hci_sched_acl_blk(struct hci_dev *hdev) { unsigned int cnt = hdev->block_cnt; struct hci_chan *chan; struct sk_buff *skb; int quote; u8 type; + bool sched_limit = hci_sched_limit(hdev); + bool resched = false; __check_timeout(hdev, cnt); @@ -4297,6 +4318,12 @@ static void hci_sched_acl_blk(struct hci_dev *hdev) while (hdev->block_cnt > 0 && (chan = hci_chan_sent(hdev, type, "e))) { u32 priority = (skb_peek(&chan->data_q))->priority; + + if (sched_limit && quote > 0) { + resched = true; + quote = 1; + } + while (quote > 0 && (skb = skb_peek(&chan->data_q))) { int blocks; @@ -4311,7 +4338,7 @@ static void hci_sched_acl_blk(struct hci_dev *hdev) blocks = __get_blocks(hdev, skb); if (blocks > hdev->block_cnt) - return; + return false; hci_conn_enter_active_mode(chan->conn, bt_cb(skb)->force_active); @@ -4325,33 +4352,39 @@ static void hci_sched_acl_blk(struct hci_dev *hdev) chan->sent += blocks; chan->conn->sent += blocks; } + + if (resched && cnt != hdev->block_cnt) + break; } - if (cnt != hdev->block_cnt) + if (hdev->block_cnt == 0 && cnt != hdev->block_cnt) hci_prio_recalculate(hdev, type); + + return resched; } -static void hci_sched_acl(struct hci_dev *hdev) +static bool hci_sched_acl(struct hci_dev *hdev) { BT_DBG("%s", hdev->name); /* No ACL link over BR/EDR controller */ if (!hci_conn_num(hdev, ACL_LINK) && hdev->dev_type == HCI_PRIMARY) - return; + goto done; /* No AMP link over AMP controller */ if (!hci_conn_num(hdev, AMP_LINK) && hdev->dev_type == HCI_AMP) - return; + goto done; switch (hdev->flow_ctl_mode) { case HCI_FLOW_CTL_MODE_PACKET_BASED: - hci_sched_acl_pkt(hdev); - break; + return hci_sched_acl_pkt(hdev); case HCI_FLOW_CTL_MODE_BLOCK_BASED: - hci_sched_acl_blk(hdev); - break; + return hci_sched_acl_blk(hdev); } + +done: + return false; } /* Schedule SCO */ @@ -4402,16 +4435,18 @@ static void hci_sched_esco(struct hci_dev *hdev) } } -static void hci_sched_le(struct hci_dev *hdev) +static bool hci_sched_le(struct hci_dev *hdev) { struct hci_chan *chan; struct sk_buff *skb; int quote, cnt, tmp; + bool sched_limit = hci_sched_limit(hdev); + bool resched = false; BT_DBG("%s", hdev->name); if (!hci_conn_num(hdev, LE_LINK)) - return; + return resched; cnt = hdev->le_pkts ? hdev->le_cnt : hdev->acl_cnt; @@ -4420,6 +4455,12 @@ static void hci_sched_le(struct hci_dev *hdev) tmp = cnt; while (cnt && (chan = hci_chan_sent(hdev, LE_LINK, "e))) { u32 priority = (skb_peek(&chan->data_q))->priority; + + if (sched_limit && quote > 0) { + resched = true; + quote = 1; + } + while (quote-- && (skb = skb_peek(&chan->data_q))) { BT_DBG("chan %p skb %p len %d priority %u", chan, skb, skb->len, skb->priority); @@ -4437,6 +4478,9 @@ static void hci_sched_le(struct hci_dev *hdev) chan->sent++; chan->conn->sent++; } + + if (resched && cnt != tmp) + break; } if (hdev->le_pkts) @@ -4444,24 +4488,33 @@ static void hci_sched_le(struct hci_dev *hdev) else hdev->acl_cnt = cnt; - if (cnt != tmp) + if (cnt == 0 && cnt != tmp) hci_prio_recalculate(hdev, LE_LINK); + + return resched; } static void hci_tx_work(struct work_struct *work) { struct hci_dev *hdev = container_of(work, struct hci_dev, tx_work); struct sk_buff *skb; + bool resched; BT_DBG("%s acl %d sco %d le %d", hdev->name, hdev->acl_cnt, hdev->sco_cnt, hdev->le_cnt); if (!hci_dev_test_flag(hdev, HCI_USER_CHANNEL)) { /* Schedule queues and send stuff to HCI driver */ - hci_sched_acl(hdev); - hci_sched_sco(hdev); - hci_sched_esco(hdev); - hci_sched_le(hdev); + do { + /* SCO and eSCO send all packets until emptied */ + hci_sched_sco(hdev); + hci_sched_esco(hdev); + + /* Acl and Le send based on quota (priority on ACL per + * loop) + */ + resched = hci_sched_acl(hdev) || hci_sched_le(hdev); + } while (resched); } /* Send next queued raw (unknown type) packet */