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=-18.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS 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 50A0AC47095 for ; Wed, 9 Jun 2021 08:34:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B7D261375 for ; Wed, 9 Jun 2021 08:34:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237144AbhFIIgd (ORCPT ); Wed, 9 Jun 2021 04:36:33 -0400 Received: from mail.kernel.org ([198.145.29.99]:39040 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232333AbhFIIgc (ORCPT ); Wed, 9 Jun 2021 04:36:32 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3AFEA61377; Wed, 9 Jun 2021 08:34:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1623227678; bh=2l42S56pOlB4B5eGvhG+7Obwuh1Nr1bw6c4osWc31PU=; h=Subject:To:From:Date:From; b=ZI4iDuSUiAbqyIeZVLuExngRh7YNu+qApmF+NQBhJZ3yiVqQemZULlLFj2x/Z+nYG maIwwNSZdBQhv93ccxTY9kV5dZXdP3fHHUTVjmGAZNpH84YoSjdAoSP3tJyut4AjCx tpE7LNwCnvClCGq8SktNN5dDSYGDH7kKi/Ez9D2o= Subject: patch "usb: f_ncm: only first packet of aggregate needs to start timer" added to usb-linus To: maze@google.com, balbi@kernel.org, brookebasile@gmail.com, bryan.odonoghue@linaro.org, gregkh@linuxfoundation.org, lorenzo@google.com, stable@vger.kernel.org From: Date: Wed, 09 Jun 2021 10:34:28 +0200 Message-ID: <162322766823598@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org This is a note to let you know that I've just added the patch titled usb: f_ncm: only first packet of aggregate needs to start timer to my usb git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git in the usb-linus branch. The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.) The patch will hopefully also be merged in Linus's tree for the next -rc kernel release. If you have any questions about this process, please let me know. >From 1958ff5ad2d4908b44a72bcf564dfe67c981e7fe Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Maciej=20=C5=BBenczykowski?= Date: Tue, 8 Jun 2021 01:54:38 -0700 Subject: usb: f_ncm: only first packet of aggregate needs to start timer MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The reasoning for this change is that if we already had a packet pending, then we also already had a pending timer, and as such there is no need to reschedule it. This also prevents packets getting delayed 60 ms worst case under a tiny packet every 290us transmit load, by keeping the timeout always relative to the first queued up packet. (300us delay * 16KB max aggregation / 80 byte packet =~ 60 ms) As such the first packet is now at most delayed by 300us. Under low transmit load, this will simply result in us sending a shorter aggregate, as originally intended. This patch has the benefit of greatly reducing (by ~10 factor with 1500 byte frames aggregated into 16 kiB) the number of (potentially pretty costly) updates to the hrtimer. Cc: Brooke Basile Cc: Bryan O'Donoghue Cc: Felipe Balbi Cc: Lorenzo Colitti Signed-off-by: Maciej Żenczykowski Link: https://lore.kernel.org/r/20210608085438.813960-1-zenczykowski@gmail.com Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_ncm.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/usb/gadget/function/f_ncm.c b/drivers/usb/gadget/function/f_ncm.c index 0d23c6c11a13..855127249f24 100644 --- a/drivers/usb/gadget/function/f_ncm.c +++ b/drivers/usb/gadget/function/f_ncm.c @@ -1101,11 +1101,11 @@ static struct sk_buff *ncm_wrap_ntb(struct gether *port, ncm->ndp_dgram_count = 1; /* Note: we skip opts->next_ndp_index */ - } - /* Delay the timer. */ - hrtimer_start(&ncm->task_timer, TX_TIMEOUT_NSECS, - HRTIMER_MODE_REL_SOFT); + /* Start the timer. */ + hrtimer_start(&ncm->task_timer, TX_TIMEOUT_NSECS, + HRTIMER_MODE_REL_SOFT); + } /* Add the datagram position entries */ ntb_ndp = skb_put_zero(ncm->skb_tx_ndp, dgram_idx_len); -- 2.32.0