From patchwork Tue Jun 28 04:33:30 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Seymour, Shane M" X-Patchwork-Id: 641354 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming@ozlabs.org Delivered-To: patchwork-incoming@ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 3rdwNs0clqz9sCp for ; Tue, 28 Jun 2016 16:09:01 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752436AbcF1GIu (ORCPT ); Tue, 28 Jun 2016 02:08:50 -0400 Received: from mail-bn1bn0107.outbound.protection.outlook.com ([157.56.110.107]:8962 "EHLO na01-bn1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751017AbcF1GIr convert rfc822-to-8bit (ORCPT ); Tue, 28 Jun 2016 02:08:47 -0400 X-Greylist: delayed 4792 seconds by postgrey-1.27 at vger.kernel.org; Tue, 28 Jun 2016 02:08:47 EDT Received: from CS1PR84MB0295.NAMPRD84.PROD.OUTLOOK.COM (10.162.190.26) by CS1PR84MB0295.NAMPRD84.PROD.OUTLOOK.COM (10.162.190.26) with Microsoft SMTP Server (TLS) id 15.1.528.16; Tue, 28 Jun 2016 04:33:30 +0000 Received: from CS1PR84MB0295.NAMPRD84.PROD.OUTLOOK.COM ([10.162.190.26]) by CS1PR84MB0295.NAMPRD84.PROD.OUTLOOK.COM ([10.162.190.26]) with mapi id 15.01.0528.017; Tue, 28 Jun 2016 04:33:30 +0000 From: "Seymour, Shane M" To: "netdev@vger.kernel.org" Subject: [PATCH net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT Thread-Topic: [PATCH net-next] tcp: increase size at which tcp_bound_to_half_wnd bounds to > TCP_MSS_DEFAULT Thread-Index: AdHQ9iJkwnhIIFRES/K3OfD8UtJ6DQ== Date: Tue, 28 Jun 2016 04:33:30 +0000 Message-ID: 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=shane.seymour@hpe.com; x-originating-ip: [110.149.145.127] x-ms-office365-filtering-correlation-id: 438f70dc-d0b3-4e65-3305-08d39f0d5b5a x-microsoft-exchange-diagnostics: 1; CS1PR84MB0295; 6:vMzGBVFzNg8IyRT9aZ7e0hDPPBNuOYg3a4Wtpk7898Rswjo0uVZVnghK6JiT1BY7V6Aw0oXcGsxkr/xBxCmVUnhUSTy66a5w8Slv4n+6QfTzWElQPxoPfT951p6OYVKatxx0YLrQweeuXbmm0zfEmhEKrDZav3kPfrElw49HHMbFY6uVPzui0bTxRyT21Lr+u/A2aQ8D/ab6b89kY5g/bu1i4J22HlRvS7VDW22tO9sV8W6Mdl5XHdnakXwoyPG6QVv0PtZyjNl8v07qIhCfKLnV+xrx5X5b9AfSs9udFfA=; 5:RMA9kRCL+GKXw/swxxhIjtIJCfxmn/IDMVkSp2dzbaql97k5p/KG7JEfR8HxhrnARsicE3EwWmwlPhlA9ZiTCpiKH3NLLa1Qplkhl53EofDTkftcwW3RHJyiShbPERmIsprfRCSnsqL17BNmPDGm9A==; 24:woWD2KFQ42A9refCTcqOBXu5MTS669TLDWDXyQ+l5IJSwsuJ4AU5dPHJQ14gAvM370vqShNVZPsoSY65NZm8vyd3JOHsdofseFlPtYASg0A=; 7:yvo7/hTYHRo8NHKMRBkTFO/KN3BexgWdm/iHNYK8nhfnqzdQPqt4lAXhUwzMhcLplal3sYjES2TK4Gz9vgxSmr/RceUAO/BrS52eqDhpBuyPvVsb0effqa49Bj9VVDj/waf/2SfMK5+64C8p2PCANK+a0LEpRH2nI82Zl/Q8GvZtx3+ZfmA8xb8IveyLqK0cdgDwUn4pkpHKDgZED2bVmMN49oJHK7qIvyGx3jt4/DpdTwDCyCEsis3sbRSYUPXA x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CS1PR84MB0295; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(227479698468861); x-exchange-antispam-report-cfa-test: BCL:0; PCL:0; RULEID:(601004)(2401047)(5005006)(8121501046)(10201501046)(3002001); SRVR:CS1PR84MB0295; BCL:0; PCL:0; RULEID:; SRVR:CS1PR84MB0295; x-forefront-prvs: 0987ACA2E2 x-forefront-antispam-report: SFV:NSPM; SFS:(10019020)(6009001)(7916002)(189002)(199003)(11100500001)(3846002)(9686002)(122556002)(7846002)(6116002)(3660700001)(102836003)(66066001)(87936001)(8676002)(81156014)(2501003)(81166006)(2906002)(68736007)(7736002)(7696003)(5003600100003)(305945005)(92566002)(2900100001)(1730700003)(10400500002)(86362001)(2351001)(3280700002)(229853001)(110136002)(107886002)(97736004)(189998001)(77096005)(105586002)(101416001)(99286002)(106356001)(5002640100001)(586003)(450100001)(54356999)(33656002)(50986999)(19580405001)(575784001)(19580395003)(8936002)(106533001); DIR:OUT; SFP:1102; SCL:1; SRVR:CS1PR84MB0295; H:CS1PR84MB0295.NAMPRD84.PROD.OUTLOOK.COM; FPR:; SPF:None; PTR:InfoNoRecords; MX:1; A:1; LANG:en; received-spf: None (protection.outlook.com: hpe.com does not designate permitted sender hosts) spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM MIME-Version: 1.0 X-OriginatorOrg: hpe.com X-MS-Exchange-CrossTenant-originalarrivaltime: 28 Jun 2016 04:33:30.4540 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 105b2061-b669-4b31-92ac-24d304d195dc X-MS-Exchange-Transport-CrossTenantHeadersStamped: CS1PR84MB0295 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org In previous commit 01f83d69844d307be2aa6fea88b0e8fe5cbdb2f4 the following comments were added: "When peer uses tiny windows, there is no use in packetizing to sub-MSS pieces for the sake of SWS or making sure there are enough packets in the pipe for fast recovery." The test should be > TCP_MSS_DEFAULT not >= 512. This allows low end devices that send an MSS of 536 (TCP_MSS_DEFAULT) to see better network performance by sending it 536 bytes of data at a time instead of bounding to half window size (268). Other network stacks work this way, e.g. HP-UX. Signed-off-by: Shane Seymour --- b/include/net/tcp.h 2016-06-23 20:59:14.521686048 -0500 +++ a/include/net/tcp.h 2016-06-15 17:19:21.964821477 -0500 @@ -589,7 +589,7 @@ static inline int tcp_bound_to_half_wnd( * On the other hand, for extremely large MSS devices, handling * smaller than MSS windows in this way does make sense. */ - if (tp->max_window > TCP_MSS_DEFAULT) + if (tp->max_window >= 512) cutoff = (tp->max_window >> 1); else cutoff = tp->max_window;