From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail2.candelatech.com ([208.74.158.173]:34752 "EHLO mail2.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753762AbbBBVZ2 (ORCPT ); Mon, 2 Feb 2015 16:25:28 -0500 Message-ID: <54CFEB46.3050006@candelatech.com> (sfid-20150202_222535_918906_F24D1EC9) Date: Mon, 02 Feb 2015 13:25:26 -0800 From: Ben Greear MIME-Version: 1.0 To: Eric Dumazet CC: Michal Kazior , linux-wireless , Network Development , eyalpe@dev.mellanox.co.il Subject: Re: Throughput regression with `tcp: refine TSO autosizing` References: <1422537297.21689.15.camel@edumazet-glaptop2.roam.corp.google.com> <1422628835.21689.95.camel@edumazet-glaptop2.roam.corp.google.com> <1422903136.21689.114.camel@edumazet-glaptop2.roam.corp.google.com> In-Reply-To: <1422903136.21689.114.camel@edumazet-glaptop2.roam.corp.google.com> Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 02/02/2015 10:52 AM, Eric Dumazet wrote: > On Mon, 2015-02-02 at 11:27 +0100, Michal Kazior wrote: > >> While testing I've had my internal GRO patch for ath10k and no stretch >> ack patches. > > Thanks for the data, I took a look at it. > > I am afraid this GRO patch might be the problem. > > It seems to break ACK clocking badly (linux stack has a somewhat buggy > tcp_tso_should_defer(), which relies on ACK being received smoothly, as > no timer is setup to split the TSO packet.) It is a big throughput win to have fewer TCP ack packets on wireless since it is a half-duplex environment. Is there anything we could improve so that we can have fewer acks and still get good tcp stack behaviour? Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com