From patchwork Thu Mar 12 18:10:54 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: 11435169 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 9A224913 for ; Thu, 12 Mar 2020 18:11:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 78BF520724 for ; Thu, 12 Mar 2020 18:11:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="j9EWbDux" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726579AbgCLSLD (ORCPT ); Thu, 12 Mar 2020 14:11:03 -0400 Received: from mail-pf1-f195.google.com ([209.85.210.195]:46192 "EHLO mail-pf1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726436AbgCLSLC (ORCPT ); Thu, 12 Mar 2020 14:11:02 -0400 Received: by mail-pf1-f195.google.com with SMTP id c19so3636365pfo.13 for ; Thu, 12 Mar 2020 11:11:02 -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:mime-version :content-transfer-encoding; bh=1r2hqBwaO/kXT5sadF+nxqNCtN3Dus3oicu3doTosoE=; b=j9EWbDuxdtPVrVMGo4g9ExD52Du4/T/igLgDcH42KRTjU6y75HsFQkhrQ/bwHZ3/O6 7mkGbWdalaG0JS7k3bYNBIm66Z8Iml9+4mPN8AmEuunwcmVpaSYTdHXLemTTceKsBsU+ plUohAf86OM+LkovQFpdDLktjvutMG0n3IurE= 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:mime-version :content-transfer-encoding; bh=1r2hqBwaO/kXT5sadF+nxqNCtN3Dus3oicu3doTosoE=; b=E7rhBvGaTmN0Tu/ZlDknBQ1Ylk22DtOG8efK7eZtw6kjrhw8S53/+FuDRQFCoNPhu2 iJkocDY81Q0LzWSAPNQAg0i45jh5UTGcTWikNuFKaHyVaDRTR1JUspvceLDlEgf+oD3h 4gOOAdti5jbnwsnLdeW4eINNg93lrc2/lf4BuuXABD7uq9AmVYm0nugxyX4HRWw7faGz IQFH8NqUO+tvnvTxwX7CNZ7yCf3z2d7ELbYv0kh9vvRx+RPQFJngz0t3Ri6gSwrjs6bN JLocefCymo10T8L9fAQvHPAl0DOSzxqyfICwPm69m+199x6lts4/N1b7N60A+64fQEbK zfMQ== X-Gm-Message-State: ANhLgQ3/N806v085AUh56ySYpyXw3zjjJ76B8tHyZjhWkKoTOzUuigwb /ad+XO2u1cLXAYqJIFQdn+Dz1g== X-Google-Smtp-Source: ADFU+vu7HWZMs5iJFzE+oa997HRVSVS4ZUzn+3cxJq0K5Cw2fuo9QjichDhlzf8YgyHRaX8xraS3PQ== X-Received: by 2002:a62:144c:: with SMTP id 73mr7218549pfu.265.1584036661706; Thu, 12 Mar 2020 11:11:01 -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.63.2020.03.12.11.11.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Mar 2020 11:11:01 -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 0/1] Bluetooth: Prioritize sco traffic on slow interfaces Date: Thu, 12 Mar 2020 11:10:54 -0700 Message-Id: <20200312181055.94038-1-abhishekpandit@chromium.org> X-Mailer: git-send-email 2.25.1.481.gfbce0eb801-goog MIME-Version: 1.0 Sender: linux-bluetooth-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi linux-bluetooth, While investigating supporting Voice over HCI/UART, we discovered that it is possible for SCO packet deadlines to be missed in some conditions where large ACL packets are being transferred. For UART, at a baudrate of 3000000, a single 1024 byte packet will take ~3.4ms to transfer. Sending two ACL packets of max size would cause us to miss the timing for SCO (which is 3.75ms) in the worst case. To mitigate this, we change hci_tx_work to prefer scheduling SCO/eSCO over ACL/LE and modify the hci_sched_{acl,le} routines so that they will only send one packet before checking whether a SCO packet is queued. ACL packets should still get sent at a similar rate (depending on number of ACL packets supported by controller) since the loop will continue until there is no more quota left for ACL and LE packets. To test this patch, I played some music over SCO (open youtube and a video conference page at the same time) while using an LE keyboard. There were no discernible slowdowns caused by this change. Thanks Abhishek Abhishek Pandit-Subedi (1): Bluetooth: Prioritize SCO traffic on slow interfaces include/net/bluetooth/hci_core.h | 1 + net/bluetooth/hci_core.c | 91 +++++++++++++++++++++++++------- 2 files changed, 73 insertions(+), 19 deletions(-)