From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-x22b.google.com (mail-oi0-x22b.google.com [IPv6:2607:f8b0:4003:c06::22b]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id A06BE3B25E for ; Tue, 12 Jul 2016 09:03:43 -0400 (EDT) Received: by mail-oi0-x22b.google.com with SMTP id w18so21077011oiw.3 for ; Tue, 12 Jul 2016 06:03:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=J+YhPxn+cXH6V4exXB60znWogZkUZv91iMs8HRhfslY=; b=aveTSsGn9mEIoU2HJbjSDy8q+AgriHelKchJD6IkgobDMkJkZSUFB7cGmOPygL7D1e BOgZ+uUvu4NC0uwWdn6VCPlGWT6XmNZ0D3437l2KqLAxWK2dBpfpBbWYOe60PoTXzzeJ ZSXsqiGM5mjPAee1w0V0ZOQY+H1Ik99i/R3jVZ5g5K0JHSskkHG64dF64Z4psiF4D983 spQ+m391BRQ2D4VH66TN8dazPjgfSRq+Apmw4K0p2o1pY4t5GL2b9z7ArB/di1Cgvnm6 WaJe5kiDX9Hj831d4I+/vW2/xoGaJLXeehtbKW3BxO6jjjM45KKiOUXiSfKszYMilhRJ EsVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=J+YhPxn+cXH6V4exXB60znWogZkUZv91iMs8HRhfslY=; b=Plhg7MW5sIH4uD0zXBaz5PgIoFk/jE+pB/LpGTRZ4Y0KcbodJqOTJ7ZnlK/6+TkopX o5csOT9zjkcm15JMkW1oY4CSshYT1BdUoUGgecQUkAJood2rvyIXTjijWe9+BoMqJjMS cZaHTP3K8ABXuZ61EROpVSzjj7IcTg5pSszh8FmRVOjWLPvRgWq+HCGmcpEEhYoYEFWk h1+mwtINaK444TEMEysI7E+E/mI12qBgTGpCbBLjl1NIS1xfpPk9GXQskawvj0a1BiMQ jeSQnfEGpCtXZF7CLMC2kHaF7JblgS83PSDk/0z53QIyCKg0pEXPkiasOdXvLnd9HUDA S7Xg== X-Gm-Message-State: ALyK8tKC+UR1bbH07joQ7QJGs7lTLTlnjFvKgu6TwGCLBAZrUxLB366pxu3svbOSWvNqAGddyNH8HhqrBBuaag== X-Received: by 10.202.224.136 with SMTP id x130mr13731283oig.105.1468328622967; Tue, 12 Jul 2016 06:03:42 -0700 (PDT) MIME-Version: 1.0 Received: by 10.202.230.71 with HTTP; Tue, 12 Jul 2016 06:03:42 -0700 (PDT) In-Reply-To: <87bn23ui87.fsf@toke.dk> References: <11fa6d16-21e2-2169-8d18-940f6dc11dca@nbd.name> <87shvfujl4.fsf@toke.dk> <87bn23ui87.fsf@toke.dk> From: Dave Taht Date: Tue, 12 Jul 2016 15:03:42 +0200 Message-ID: To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Felix Fietkau , linux-wireless , Michal Kazior , make-wifi-fast@lists.bufferbloat.net Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: Re: [Make-wifi-fast] TCP performance regression in mac80211 triggered by the fq code X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 12 Jul 2016 13:03:43 -0000 On Tue, Jul 12, 2016 at 2:57 PM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Dave Taht writes: > >>> As for why this would happen... There could be a bug in the dequeue cod= e >>> somewhere, but since you get better performance from sticking everythin= g >>> into one queue, my best guess would be that the client is choking on th= e >>> interleaved packets? I.e. expending more CPU when it can't stick >>> subsequent packets into the same TCP flow? >> >> I share this concern. >> >> The quantum is? I am not opposed to a larger quantum (2 full size >> packets =3D 3028 in this case?). > > The quantum is hard-coded to 300 bytes in the current implementation > (see net/fq_impl.h). don't do that. :) A single full size packet is preferable, and saves going around the main dequeue loop 5-6 times per flow on this workload. My tests on the prior patch set were mostly at the larger quantum. > -Toke --=20 Dave T=C3=A4ht Let's go make home routers and wifi faster! With better software! http://blog.cerowrt.org