From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-da0-f43.google.com (mail-da0-f43.google.com [209.85.210.43]) (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 4958F21F168; Wed, 28 Nov 2012 10:51:07 -0800 (PST) Received: by mail-da0-f43.google.com with SMTP id u36so7650346dak.16 for ; Wed, 28 Nov 2012 10:51:06 -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=6hGxVRbPZDYmOZSjBidcR0O7Wk65lMjuDIP/mdWr6zc=; b=wjsarM8eGN1XxkEywBPuBXgVVu6jwqdGP9h2QQYeB2WR4uA/7IKSYfNdTXogCywfdV z5VvDACrm2DJV9jEc4q6dWzXjxORViP/W4TmOmc92sPYj+nd2cnOMEXWTjZZv/+jjBnh Vj4wCjwJPr0VAFNhkmNkJrV/n3mbgy/KFoVUKwyAhAwkTTDNPbh1LlvfHvmSaMip7SMn 6PnhUk2diDPZWw7wcihzgGpJI9B+ltt7XGWIDDSB9joLg0kMHMkV1WOkvzSDkE/SRFoZ w1cJcmNyFf/OzJaBeo9z5IMiNj1YIa/VIb8k287x4ERZ13OjJFJGIWwa8zvkIAnWB4ta NaoQ== Received: by 10.68.240.36 with SMTP id vx4mr60601704pbc.90.1354128666748; Wed, 28 Nov 2012 10:51:06 -0800 (PST) Received: from [172.26.49.229] ([172.26.49.229]) by mx.google.com with ESMTPS id uh10sm12835175pbc.35.2012.11.28.10.51.04 (version=SSLv3 cipher=OTHER); Wed, 28 Nov 2012 10:51:05 -0800 (PST) From: Eric Dumazet To: Michael Richardson In-Reply-To: <7700.1354127857@obiwan.sandelman.ca> References: <20121127224915.GM2474@linux.vnet.ibm.com> <20121128002710.GS2474@linux.vnet.ibm.com> <50B5887C.7010605@pollere.com> <20121128043838.GX2474@linux.vnet.ibm.com> <20121128160133.GA16995@linux.vnet.ibm.com> <20121128174440.GD2474@linux.vnet.ibm.com> <7700.1354127857@obiwan.sandelman.ca> Content-Type: text/plain; charset="UTF-8" Date: Wed, 28 Nov 2012 10:51:03 -0800 Message-ID: <1354128663.14302.488.camel@edumazet-glaptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Content-Transfer-Encoding: 7bit Cc: John Crispin , "codel@lists.bufferbloat.net" , "cerowrt-devel@lists.bufferbloat.net" , bloat Subject: Re: [Bloat] [Codel] [Cerowrt-devel] FQ_Codel lwn draft article review X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 28 Nov 2012 18:51:07 -0000 On Wed, 2012-11-28 at 13:37 -0500, Michael Richardson wrote: > >>>>> "Paul" == Paul E McKenney writes: > Paul> You lost me on this one. It looks to me like > Paul> net/sched/sch_fq_codel.c > Paul> in fact does hash packets into flows, so FQ-CoDel is > Paul> stochastic in the > Paul> the same sense that SFQ is. In particular, FQ-CoDel can hash a thin > Paul> session into the same flow as a thick session, which really is the > Paul> birthday effect. > > Silly question from someone who should read more code, but... > if one is hashing the packet to pick a flow bucket, shouldn't this hash > occur before any application of address/port translation. ? (NAT) > > (Maybe I've just found out that IPv6 + CoDel will be a killer > combination) > Why would it be a killer ? A NATed flow becomes another flow, with its own hash A tunnel might have a problem, _if_ the hash would be computed on elements found on the outer header. But luckily, we do a complete flow dissection. (Assuming the default fq_codel classification)