From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ie0-f171.google.com (mail-ie0-f171.google.com [209.85.223.171]) (using TLSv1 with cipher RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id DE14221F169 for ; Wed, 21 Nov 2012 23:57:09 -0800 (PST) Received: by mail-ie0-f171.google.com with SMTP id 17so7709800iea.16 for ; Wed, 21 Nov 2012 23:57:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:from:to:cc:in-reply-to:references:content-type:date :message-id:mime-version:x-mailer:content-transfer-encoding; bh=DuZScm2tG8QjbBC2eDNjt+Ygg5UU0BXKpMFiNDwiR2w=; b=wBeaDFhXU15eVZdm6Si5/n+8G6YzmBL1UOJaLQgcX/dM+cno6U5K2fNr3CBMgGZ77U 3OongQ6dxvVhH7SzdDxYkzQ0lmSqzQ8ak/7+eH1ZFlRyjTfXYoxjceXox+LbKEwgvphc jtXKXpnSkt3AID9KhZRzj+WaWDPI+28n01O28+erGDkchHH9RpXDIVrruQ3DPL0t6hOQ jFDAuo/A/awaHYZup1Aa1p5j0IjsQUuKn3K+7HMwcSB7DDrhCz9PyOTE08aWnQDGAM3B 2ts08PP8xZ3SwS0THUd8Gd0kzuvBoHEKhGHJWV5i2339IYSiaa3EopUqg//pufNq9IZF IjLQ== Received: by 10.50.53.147 with SMTP id b19mr2396345igp.12.1353571028957; Wed, 21 Nov 2012 23:57:08 -0800 (PST) Received: from [192.168.1.75] (99-119-65-64.lightspeed.sntcca.sbcglobal.net. [99.119.65.64]) by mx.google.com with ESMTPS id uj11sm1633013igb.15.2012.11.21.23.57.07 (version=SSLv3 cipher=OTHER); Wed, 21 Nov 2012 23:57:08 -0800 (PST) From: Eric Dumazet To: Dave Taht In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" Date: Wed, 21 Nov 2012 23:57:06 -0800 Message-ID: <1353571026.2590.731.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Cc: David Woodhouse , codel@lists.bufferbloat.net Subject: Re: [Codel] GRO (generic receive offload) is not helpful with codel and fq_codel X-BeenThere: codel@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: CoDel AQM discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 Nov 2012 07:57:10 -0000 On Thu, 2012-11-22 at 08:22 +0100, Dave Taht wrote: > qdisc fq_codel 120: parent 1:12 limit 10240p flows 16000 quantum 500 > target 20.0ms interval 100.0ms > Sent 2213780 bytes 4843 pkt (dropped 48, overlimits 0 requeues 0) > backlog 12160b 8p requeues 0 > maxpacket 14546 drop_overlimit 0 new_flow_count 1237 ecn_mark 0 > ******* > new_flows_len 1 old_flows_len 2 Yes, GRO/TSO are not good for speeds below 10Mb. In your case, you probably have one Gigabit ethernet (allowing GRO packets being constructed), forwarding to the WAN at 750 kbits ... Definitely GRO should be turned off in this case. A GSO packet of 64KB would take about 600ms to be transmitted ! Ideally, we should segment GSO packets at these low forwarding rates, and keep GRO turned on for local traffic (not forwarded)