From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from plane.gmane.org (plane.gmane.org [80.91.229.3]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 4E98821F19A for ; Tue, 19 May 2015 14:01:29 -0700 (PDT) Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1YuodQ-0001vE-09 for bloat@lists.bufferbloat.net; Tue, 19 May 2015 23:01:08 +0200 Received: from host-89-243-100-239.as13285.net ([89.243.100.239]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 May 2015 23:01:07 +0200 Received: from alan.christopher.jenkins by host-89-243-100-239.as13285.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Tue, 19 May 2015 23:01:07 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: bloat@lists.bufferbloat.net From: Alan Jenkins Date: Tue, 19 May 2015 22:00:46 +0100 Message-ID: <555BA47E.2050707@gmail.com> References: <555B34DD.2050102@kit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: host-89-243-100-239.as13285.net User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 In-Reply-To: <555B34DD.2050102@kit.edu> Cc: aqm@ietf.org Subject: Re: [Bloat] Any aqm evaluation at speeds >=10Gbit/s? 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: Tue, 19 May 2015 21:02:15 -0000 On 19/05/15 14:04, Bless, Roland (TM) wrote: > Hi, > > has anyone recently tested AQMs like Codel or PIE > at speeds of >=10Gbit/s? If so, where are the results available? > Pointers greatly appreciated... > > Regards, > Roland I know only background information on that. 1) fq_codel was written by Eric Dumazet of Google and tested at 10G. Allegedly at 10G CoDel works fine, and fq_codel costs "2% of a single modern CPU core". Sounds trustworthy but that doesn't give you any details :). Cite: Jim Gettys. Codel: https://gettys.wordpress.com/2012/05/22/a-milestone-reached-codel-is-in-linux/ fq_codel: https://www.ietf.org/proceedings/87/slides/slides-87-aqm-6.pdf [Whether router queue management can achieve anything for a 10g link which also has high multiplexing and 50%+ exponential 'slow start' with IW10... I think we didn't have an answer ready when that came up.] 2) Eric also wrote sch_fq and tested it at 10G. sch_fq is only designed for end hosts and is not designed or implemented to reduce latency AIUI. [I may finally understand this article https://lwn.net/Articles/564978/ For our bufferbloat at the ISP network edge, the more important part of the article is TSO sizing. Which does not depend on qdisc. sch_fq just does TCP pacing (and flow queuing). sch_fq pacing doesn't affect slow start _or_ saturating ("ack clocked") flows, which are the causes of edge bufferbloat. It could do, but Eric's next priority is to improve TCP congestion control. https://lists.bufferbloat.net/pipermail/bloat/2015-April/002797.html https://lists.bufferbloat.net/pipermail/bloat/2015-April/002801.html] What does sch_fq actually pace? Well, "you no longer have to slow start after idle", so it should help things like re-used HTTP connections. But I think the implication is also for consistent flows that don't saturate: media streaming. https://lists.bufferbloat.net/pipermail/bloat/2015-April/002764.html] Alan