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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 CEA45C2D0C8 for ; Tue, 17 Dec 2019 11:01:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9451F2082E for ; Tue, 17 Dec 2019 11:01:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=silabs.onmicrosoft.com header.i=@silabs.onmicrosoft.com header.b="OWsgohQO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727170AbfLQLBq (ORCPT ); Tue, 17 Dec 2019 06:01:46 -0500 Received: from mail-eopbgr770085.outbound.protection.outlook.com ([40.107.77.85]:53526 "EHLO NAM02-SN1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725870AbfLQLBp (ORCPT ); Tue, 17 Dec 2019 06:01:45 -0500 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=CBK6egodDM8heHFHSPoV/U/8CBgdvJJHu0afOZ+EGqfmz2lRbFBBrQAKuQhe0o4UjsQkIM2YN8W+OCN6vsGhi52Zp20mmHcJKKQWA4u/W9Px1DQYlDBq82JJqCzcFH2Im6oGEoYi6rm35Jd6A9BA+job7jQLbtcQ897Fz38HP2jj9s8EaYiGhCKKniaMgnd7lNX7T3XOvWoex9D0cHfHaJ6okySzLa4UZh7cacZxkS3gMgErau1wniHbUtXuTZOkvVYucRRnhn42xuNXnQ8rbnWPV2lAEBDI5gb7kCD0t/Z2WNGK2VAeMVFSHVEFyhqoDfw3G/WnuQh50wIwMUNWYg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=8TbthLPrlbPDnOfoKDUmoVo9r0/Jb+RMoq4uT+F2PJQ=; b=ZWjZu1Tq/cq8W/jjSuwGhbiw+dJiNn0j/ZEZ7biE9hMG+/9GPM3OeGQvbigdeYdmsaIYYRolgKFOL+bC+4IbJZdmTWlckX+e0A6DViiTxczg/52oEEdza/FrzmvxRkDHHF+M8TxYbxTTtdWo30XoZodVmHtcjBU9r+OIeBpFdnCxanIZdiHgoTHBVlw+OkT8UDuAObmc9rl8fVdYeBrvM4UUk9Wq5oJ/mt2cCZJ54jrk3Y8rU7lEBUpyoA+//YphrukVP69xZqei/VS3Cwv6m3AyxquDmvKP8ruxkgFg72VRis0W0/2IJxbu48mN/wEAoSl/GDd++oKRdFJLQBkLww== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=silabs.com; dmarc=pass action=none header.from=silabs.com; dkim=pass header.d=silabs.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=silabs.onmicrosoft.com; s=selector2-silabs-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=8TbthLPrlbPDnOfoKDUmoVo9r0/Jb+RMoq4uT+F2PJQ=; b=OWsgohQO0YjGGiCj/PUDnIkrw+TUGf3hQRFNNq80e/706xm4BeWlsPVabh30rN8vZJKiRY+8m+g6TjNSa90qaHHFjr7pCtBcD+oqYZT1fArQ5SHzJeBcvU6pZjOflPBv21A04ecLlC2GxWqEwpzoOxDgUzBHqtGGyUHs+JVIph0= Received: from MN2PR11MB4063.namprd11.prod.outlook.com (10.255.180.22) by MN2PR11MB4461.namprd11.prod.outlook.com (52.135.39.93) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2538.17; Tue, 17 Dec 2019 11:01:43 +0000 Received: from MN2PR11MB4063.namprd11.prod.outlook.com ([fe80::f46c:e5b4:2a85:f0bf]) by MN2PR11MB4063.namprd11.prod.outlook.com ([fe80::f46c:e5b4:2a85:f0bf%4]) with mapi id 15.20.2538.019; Tue, 17 Dec 2019 11:01:43 +0000 From: =?iso-8859-1?Q?J=E9r=F4me_Pouiller?= To: Felix Fietkau CC: "devel@driverdev.osuosl.org" , "linux-wireless@vger.kernel.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Greg Kroah-Hartman , Kalle Valo , "David S . Miller" Subject: Re: [PATCH 07/55] staging: wfx: ensure that retry policy always fallbacks to MCS0 / 1Mbps Thread-Topic: [PATCH 07/55] staging: wfx: ensure that retry policy always fallbacks to MCS0 / 1Mbps Thread-Index: AQHVtDLBov0Pg1nqV0CYOt2kPrSx7ae9D0mAgAEbCoA= Date: Tue, 17 Dec 2019 11:01:42 +0000 Message-ID: <3755885.sodJc2dsoe@pc-42> References: <20191216170302.29543-1-Jerome.Pouiller@silabs.com> <20191216170302.29543-8-Jerome.Pouiller@silabs.com> <0777ef33-e1f4-148a-40cb-cfe7b42d5364@nbd.name> In-Reply-To: <0777ef33-e1f4-148a-40cb-cfe7b42d5364@nbd.name> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Jerome.Pouiller@silabs.com; x-originating-ip: [37.71.187.125] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 6d9de33d-b94e-4191-6261-08d782e08028 x-ms-traffictypediagnostic: MN2PR11MB4461: x-microsoft-antispam-prvs: x-ms-oob-tlc-oobclassifiers: OLM:8882; x-forefront-prvs: 02543CD7CD x-forefront-antispam-report: SFV:NSPM;SFS:(10009020)(7916004)(136003)(366004)(376002)(346002)(39850400004)(396003)(199004)(189003)(6506007)(71200400001)(316002)(91956017)(76116006)(66556008)(33716001)(66476007)(66446008)(6916009)(64756008)(54906003)(478600001)(66946007)(26005)(6486002)(9686003)(6512007)(81166006)(66574012)(5660300002)(8936002)(86362001)(81156014)(4326008)(2906002)(186003)(53546011)(4001150100001)(8676002)(39026012);DIR:OUT;SFP:1101;SCL:1;SRVR:MN2PR11MB4461;H:MN2PR11MB4063.namprd11.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;A:1;MX:1; received-spf: None (protection.outlook.com: silabs.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: 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 x-ms-exchange-transport-forked: True Content-Type: text/plain; charset="iso-8859-1" Content-ID: <1D0704F34739504DB32815630A19F424@namprd11.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: silabs.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6d9de33d-b94e-4191-6261-08d782e08028 X-MS-Exchange-CrossTenant-originalarrivaltime: 17 Dec 2019 11:01:42.8181 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 54dbd822-5231-4b20-944d-6f4abcd541fb X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: ABHEEATnkS2RafS72jTmvMb62lGw56SdI77944eyNmuN97xPNY9OmlJkGnhS34B+83pF4OQZOXFHHlZ8TDnAtw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR11MB4461 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Monday 16 December 2019 19:08:39 CET Felix Fietkau wrote: > On 2019-12-16 18:03, J=E9r=F4me Pouiller wrote: > > From: J=E9r=F4me Pouiller > > > > When not using HT mode, minstrel always includes 1Mbps as fallback rate= . > > But, when using HT mode, this fallback is not included. Yet, it seems > > that it could save some frames. So, this patch add it unconditionally. > > > > Signed-off-by: J=E9r=F4me Pouiller > Are you sure that's a good idea? Sometimes a little packet loss can be > preferable over a larger amount of airtime wasted through using really > low rates. Especially when you consider bufferbloat. Hello Felix, I have observed that, in some circumstances, TCP throughput was far=20 better with 802.11g than with 802.11n. I found that 802.11n had more Tx=20 failures. These failures have big impacts on the congestion window. When=20 the congestion window is low, it impacts the capacity of aggregation of=20 the link. Thus, it does not help to improve the congestion windows. By investigating deeper, it appears that the minstrel (used by 802.11g) always add rate 1Mbps to the rate list while minstrel_ht (used by 802.11n) don't (compare minstrel_update_rates() and minstrel_ht_update_rates()). This difference seems to be correlated to the difference of TCP throughput I can observe. I did some search in git history and I did not find any explanation for=20 this difference between minstrel and minstrel_ht (however, it seems you=20 are the right person to ask :) ). I didn't find why it would be efficient on minstrel and inefficient on minstrel_ht. And since this change fix the issue that I observed, I have tried to apply it and wait for feedback. --=20 J=E9r=F4me Pouiller