From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sujith Manoharan Subject: Re: TCP performance regression Date: Mon, 11 Nov 2013 23:59:37 +0530 Message-ID: <21121.8721.391128.979811@gargle.gargle.HOWL> References: <21120.27501.32323.332316@gargle.gargle.HOWL> <1384149326.16391.10.camel@edumazet-glaptop2.roam.corp.google.com> <21120.29720.673157.151074@gargle.gargle.HOWL> <1384152853.16391.19.camel@edumazet-glaptop2.roam.corp.google.com> <21120.37647.979237.40802@gargle.gargle.HOWL> <1384180069.16391.32.camel@edumazet-glaptop2.roam.corp.google.com> <21121.575.539384.948990@gargle.gargle.HOWL> <52810800.9020402@openwrt.org> <1384191515.16391.49.camel@edumazet-glaptop2.roam.corp.google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: Eric Dumazet , Felix Fietkau , "netdev\@vger.kernel.org" To: Dave Taht Return-path: Received: from s72.web-hosting.com ([198.187.29.21]:60072 "EHLO s72.web-hosting.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753975Ab3KKSeH (ORCPT ); Mon, 11 Nov 2013 13:34:07 -0500 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Dave Taht wrote: > Personally I don't have much of a problem if TSQ hurts single stream > TCP throughput on wifi. I would vastly prefer aggregation to work > better for multiple streams with vastly smaller buffers than it does. > That would be a bigger win, overall. ath9k doesn't hold very deep queues for aggregated traffic. A maximum of 128 packets can be buffered for each Access Class queue and still good throughput is obtained, even for 3x3 scenarios. A loss of almost 50% throughput is seen in 1x1 setups and the penalty becomes higher with more streams. I don't think such a big loss in performance is acceptable to achieve low latency. Sujith