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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1EF83C433EF for ; Thu, 14 Jul 2022 12:20:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238615AbiGNMUl (ORCPT ); Thu, 14 Jul 2022 08:20:41 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36884 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230040AbiGNMUj (ORCPT ); Thu, 14 Jul 2022 08:20:39 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DB7B1FCC8; Thu, 14 Jul 2022 05:20:39 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id A9FE061D7E; Thu, 14 Jul 2022 12:20:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9A4B1C34114; Thu, 14 Jul 2022 12:20:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657801238; bh=T0bWZ1+6aus86wkYhIjKgAyY3BntT8gojmXQ4imG/vo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=tE0H5AjGN1273iOr9NHnQr7kjHz5tu052JUoUYS+gsNc8dL4dRf1XxIlP58Jgi9fb 7qS8UKDUrVnOdpf1JwRsfkaipQ5Z1MqAC50jYXugdmr1zIf1BrIJp9xsz2NQBDc3hf DUdFPSKvIrjX2Ku7Scxc7GjNkPboQsULgdckFQiA= Date: Thu, 14 Jul 2022 14:20:35 +0200 From: Greg KH To: =?utf-8?Q?=C5=81ukasz?= Spintzyk Cc: netdev@vger.kernel.org, linux-usb@vger.kernel.org, oliver@neukum.org, kuba@kernel.org, ppd-posix@synaptics.com Subject: Re: [PATCH v2 2/2] net/cdc_ncm: Increase NTB max RX/TX values to 64kb Message-ID: References: <20220714120217.18635-1-lukasz.spintzyk@synaptics.com> <20220714120217.18635-2-lukasz.spintzyk@synaptics.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220714120217.18635-2-lukasz.spintzyk@synaptics.com> Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On Thu, Jul 14, 2022 at 02:02:17PM +0200, Łukasz Spintzyk wrote: > DisplayLink ethernet devices require NTB buffers larger then 32kb > in order to run with highest performance. > > This patch is changing upper limit of the rx and tx buffers. > Those buffers are initialized with CDC_NCM_NTB_DEF_SIZE_RX and > CDC_NCM_NTB_DEF_SIZE_TX which is 16kb so by default no device is > affected by increased limit. > > Rx and tx buffer is increased under two conditions: > - Device need to advertise that it supports higher buffer size in > dwNtbMaxInMaxSize and dwNtbMaxOutMaxSize. > - cdc_ncm/rx_max and cdc_ncm/tx_max driver parameters must be adjusted > with udev rule or ethtool. > > Summary of testing and performance results: > Tests were performed on following devices: > - DisplayLink DL-3xxx family device > - DisplayLink DL-6xxx family device > - ASUS USB-C2500 2.5G USB3 ethernet adapter > - Plugable USB3 1G USB3 ethernet adapter > - EDIMAX EU-4307 USB-C ethernet adapter > - Dell DBQBCBC064 USB-C ethernet adapter > > Performance measurements were done with: > - iperf3 between two linux boxes > - http://openspeedtest.com/ instance running on local test machine > > Insights from tests results: > - All except one from third party usb adapters were not affected by > increased buffer size to their advertised dwNtbOutMaxSize and > dwNtbInMaxSize. > Devices were generally reaching 912-940Mbps both download and upload. > > Only EDIMAX adapter experienced decreased download size from > 929Mbps to 827Mbps with iper3, with openspeedtest decrease was from > 968Mbps to 886Mbps. > > - DisplayLink DL-3xxx family devices experienced performance increase > with iperf3 download from 300Mbps to 870Mbps and > upload from 782Mbps to 844Mbps. > With openspeedtest download increased from 556Mbps to 873Mbps > and upload from 727Mbps to 973Mbps > > - DiplayLink DL-6xxx family devices are not affected by > increased buffer size. > > Signed-off-by: Łukasz Spintzyk > --- > > v2: > - Information how to change tx,rx buffer size > - Added performance tests results to the commit description. > > > include/linux/usb/cdc_ncm.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/usb/cdc_ncm.h b/include/linux/usb/cdc_ncm.h > index f7cb3ddce7fb..2d207cb4837d 100644 > --- a/include/linux/usb/cdc_ncm.h > +++ b/include/linux/usb/cdc_ncm.h > @@ -53,8 +53,8 @@ > #define USB_CDC_NCM_NDP32_LENGTH_MIN 0x20 > > /* Maximum NTB length */ > -#define CDC_NCM_NTB_MAX_SIZE_TX 32768 /* bytes */ > -#define CDC_NCM_NTB_MAX_SIZE_RX 32768 /* bytes */ > +#define CDC_NCM_NTB_MAX_SIZE_TX 65536 /* bytes */ > +#define CDC_NCM_NTB_MAX_SIZE_RX 65536 /* bytes */ > > /* Initial NTB length */ > #define CDC_NCM_NTB_DEF_SIZE_TX 16384 /* bytes */ > -- > 2.36.1 > Acked-by: Greg Kroah-Hartman Thanks for the additional information in the changelog text.