From mboxrd@z Thu Jan 1 00:00:00 1970 From: arno@natisbad.org (Arnaud Ebalard) Subject: Re: [PATCH v2] tcp: tsq: restore minimal amount of queueing Date: Wed, 13 Nov 2013 22:18:12 +0100 Message-ID: <8738n0ngq3.fsf@natisbad.org> 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> Mime-Version: 1.0 Content-Type: text/plain Cc: David Miller , Sujith Manoharan , Cong Wang , netdev@vger.kernel.org, Felix Fietkau To: Eric Dumazet Return-path: Received: from smtpfb2-g21.free.fr ([212.27.42.10]:38429 "EHLO smtpfb2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751003Ab3KMVTL (ORCPT ); Wed, 13 Nov 2013 16:19:11 -0500 Received: from smtp4-g21.free.fr (smtp4-g21.free.fr [212.27.42.4]) by smtpfb2-g21.free.fr (Postfix) with ESMTP id 6EA75D129C8 for ; Wed, 13 Nov 2013 22:19:03 +0100 (CET) Received: from smtp.natisbad.org (unknown [81.57.185.249]) by smtp4-g21.free.fr (Postfix) with ESMTP id 9EAC44C81E3 for ; Wed, 13 Nov 2013 22:18:21 +0100 (CET) In-Reply-To: <1384353174.28458.110.camel@edumazet-glaptop2.roam.corp.google.com> (Eric Dumazet's message of "Wed, 13 Nov 2013 06:32:54 -0800") Sender: netdev-owner@vger.kernel.org List-ID: 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. Cheers, a+