From owner-freebsd-net@FreeBSD.ORG Sat Jul 19 03:28:11 2014 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 22302864; Sat, 19 Jul 2014 03:28:11 +0000 (UTC) Received: from mail-qa0-x22c.google.com (mail-qa0-x22c.google.com [IPv6:2607:f8b0:400d:c00::22c]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id C2B2C2EC6; Sat, 19 Jul 2014 03:28:10 +0000 (UTC) Received: by mail-qa0-f44.google.com with SMTP id f12so3614547qad.3 for ; Fri, 18 Jul 2014 20:28:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=w75OtZ7K9jbkw50JF/3vly0uRQTFw8VRS0hdBlaSZP4=; b=vZ0vMhJPvlmIUVh56qQY84qYj9n3I5yy+OFM4HiBKTkzUf9Tbpot8j+lzhftHbs5KI hpVaFrIWtmdld22dSimlX4WiT14+cWxmGQTDbwMmkCp5q+pWikowUbineZn73ttjd7mO SegsOoqTGZATe1s/QqYxISJKHC0SqK9a0/TKUiKmuZXoGQxs7gztju+KkPFl3G3XbI46 cNbWDvimbf7OgtE8fF6CCfToyMo07w6DpHDqv1mh5I7eM27ufU6ypFP24HyC1jNwxgax zHn5S0yj23T2+DQS4vLlGvsGT/RhcjVXhbDWj/PSAM8LCUTv40TixfCBDugsm0GiibuF ihBg== MIME-Version: 1.0 X-Received: by 10.229.174.70 with SMTP id s6mr14798770qcz.29.1405740489801; Fri, 18 Jul 2014 20:28:09 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.224.1.6 with HTTP; Fri, 18 Jul 2014 20:28:09 -0700 (PDT) In-Reply-To: References: <53C964F7.8060503@gmail.com> Date: Fri, 18 Jul 2014 20:28:09 -0700 X-Google-Sender-Auth: e4_Jf2H8yjiTLJmu-inCWeXE9oI Message-ID: Subject: Re: [patch][lagg] - Set a better granularity and distribution on roundrobin protocol. From: Adrian Chadd To: araujo@freebsd.org Content-Type: text/plain; charset=UTF-8 Cc: FreeBSD Net , Navdeep Parhar X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Jul 2014 03:28:11 -0000 On 18 July 2014 19:06, Marcelo Araujo wrote: > > > > 2014-07-19 2:18 GMT+08:00 Navdeep Parhar : > >> On 07/18/14 00:49, Marcelo Araujo wrote: >> > Hello guys, >> > >> > I made few changes on the lagg(4) patch. Also, I made tests using >> > igb(4), >> > ixgbe(4) and em(4); seems everything worked pretty well. >> > >> > I'm wondering if anyone else could make a review, and what I need to do, >> > to >> > see this patch committed. >> >> Deliberately putting out-of-order packets on the wire is never a good >> idea. This would count as a serious regression in lagg(4) imho. >> >> Regards, >> Navdeep >> >> > > I'm wondering if anyone have tested the patch; because as I have explained > in another email, the number of SACK is much less with this patch. I have > put some pcap files here: http://people.freebsd.org/~araujo/lagg/ > > Also, as far as I know, the current roundrobin implementation has no such > kind of mechanism to control the order of the packages that goes to the > wire. And this patch, what it only does is, instead to send only one package > through one interface and switch to the another one, it will send X(where X > is the number of packets defined via sysctl) packets and then, switch to the > next interface. > > So, could you show me, where this patch deliberately put out-of-order > packets? Did I miss anything? It doesn't introduce it, but it still continues potentially out of order behaviour depending upon CPU loading and NIC scheduling. If you're seeing reduced ACK / retransmits by doing this then there's gotta be some other underlying factor causing it. That's what I think needs to be fixed, not papering over it by more round robin hacks. :-P -a