From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Holger Hoffstaette" Subject: Re: [PATCH v2] tcp: tsq: restore minimal amount of queueing Date: Wed, 13 Nov 2013 22:59:50 +0100 Message-ID: References: <8761s0cqhh.fsf@natisbad.org> <87y54u59zq.fsf@natisbad.org> <1384267141.28458.24.camel@edumazet-glaptop2.roam.corp.google.com> <1384353174.28458.110.camel@edumazet-glaptop2.roam.corp.google.com> <8738n0ngq3.fsf@natisbad.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: netdev@vger.kernel.org Return-path: Received: from plane.gmane.org ([80.91.229.3]:40700 "EHLO plane.gmane.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751654Ab3KMWAF (ORCPT ); Wed, 13 Nov 2013 17:00:05 -0500 Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1VgiTi-000843-1V for netdev@vger.kernel.org; Wed, 13 Nov 2013 23:00:02 +0100 Received: from p5086b3f1.dip0.t-ipconnect.de ([80.134.179.241]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 13 Nov 2013 23:00:02 +0100 Received: from holger.hoffstaette by p5086b3f1.dip0.t-ipconnect.de with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 13 Nov 2013 23:00:02 +0100 Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 13 Nov 2013 22:18:12 +0100, Arnaud Ebalard wrote: > Hi Eric, > > Eric Dumazet writes: > >> From: Eric Dumazet >> >> After commit c9eeec26e32e ("tcp: TSQ can use a dynamic limit"), several >> users reported throughput regressions, notably on mvneta and wifi >> adapters. >> >> 802.11 AMPDU requires a fair amount of queueing to be effective. >> >> This patch partially reverts the change done in tcp_write_xmit() so that >> the minimal amount is sysctl_tcp_limit_output_bytes. > > I just tested the fix on current linux tree with the same setup on which I > observed the regression: it also fixes it on my side on my RN102. Thanks > for the quick fix, Eric. +1: fixes spastic NFS & Samba throughput since 3.12.0 with r8169 and e100e for me as well. It's really not just broken/weird Wifi cards that are affected by this. Thanks! -h