From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pz0-f48.google.com (mail-pz0-f48.google.com [209.85.210.48]) (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 2177B20061E for ; Sat, 5 May 2012 15:34:49 -0700 (PDT) Received: by dadz8 with SMTP id z8so1788579dad.7 for ; Sat, 05 May 2012 15:34:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=U2yZnhaDXCAz0syRmtqdRaQ9bIKrafbdEOiH7ZtgLgA=; b=XtaJUVdLFEKemUMQIcyDQ5X3uPUbjsxvTjFzRbd0J5MTcjOdzsnROJzoqrxoFk2vKB ioQ1hNZ4P5i8iVp2OkNxVtFVMtl6Yk7FXGxB00jHE04YnQqKmBdPLp/J8oLDTXxyKa7s 6cdC3MxQnhGBbI9D2fGddQIIPmePFEaCFTKKTA2JwV1y09MNf7LOiSg62SOO/kaxgevs u9znnihHTv4GjFVBhugN7xRbsMO/rcqimqi//iSZn70aP3Lg6UA0Nz3sJVOoy/NFJ3bx dYSGr/Sw08DMaDuRetwO0gZO0qVH58XuuiYaXu6JMH2faKbSeJ/5nv5bh6HkAl9bfPoJ UDXA== Received: by 10.68.125.131 with SMTP id mq3mr19119415pbb.123.1336257288570; Sat, 05 May 2012 15:34:48 -0700 (PDT) Received: from ?IPv6:2001:4f8:3:203::c001? ([2001:4f8:3:203::c001]) by mx.google.com with ESMTPS id wi6sm12992721pbc.66.2012.05.05.15.34.46 (version=SSLv3 cipher=OTHER); Sat, 05 May 2012 15:34:47 -0700 (PDT) Message-ID: <4FA5AB05.9030305@gmail.com> Date: Sat, 05 May 2012 15:34:45 -0700 From: dave taht User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120410 Thunderbird/11.0.1 MIME-Version: 1.0 To: Eric Dumazet References: <1336217671-20384-1-git-send-email-dave.taht@bufferbloat.net> <1336218794.3752.508.camel@edumazet-glaptop> <1336229343.3752.516.camel@edumazet-glaptop> <1336249251.3752.558.camel@edumazet-glaptop> <1336250168.3752.560.camel@edumazet-glaptop> <1336252281.3752.561.camel@edumazet-glaptop> <4FA597C0.7090206@gmail.com> <1336252832.3752.563.camel@edumazet-glaptop> <4FA5A3B8.7020808@gmail.com> <1336255783.3752.573.camel@edumazet-glaptop> In-Reply-To: <1336255783.3752.573.camel@edumazet-glaptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: codel@lists.bufferbloat.net, =?UTF-8?B?RGF2ZSBUw6RodA==?= Subject: Re: [Codel] [PATCH v5] pkt_sched: codel: Controlled Delay AQM 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: Sat, 05 May 2012 22:34:49 -0000 On 05/05/2012 03:09 PM, Eric Dumazet wrote: > On Sat, 2012-05-05 at 15:03 -0700, dave taht wrote: > >> Maybe on your arch, but highly doubtful on a 680Mhz mips that isn't even >> superscalar. >> > CPU are fast, memory is slow. > >> I'd prefer to leave it in and be able to compile it out, and actually >> measure the difference. > You optimize the case where there is no need to optimize (small queue) > > I can see count bigger than 100000 with 20 concurrent netperf > > This makes no sense to have a cache so big. > > Or there is a bug in codel The original reciprocol approximation test code rapidly goes AWOL after exceeding 2^8. I went looking for butterflies and didn't see any in the scaled code in the range 0-100000, and they would only take flight briefly, so... However I have not corrected it for BITS_PER_LONG as per our 4AM discussion. I will get a build going of your latest code with the stats collection and look at it harder after dinner. Get some sleep, too! fun day. value sqrt recip inv sqrt relative err scaled inv/sqrt value relative err interval/sqrt(256)=6250000 approx :6250190 1.00003040 interval/scaled: 6250000 1.00000000 interval/sqrt(257)=6237828 approx :6250190 1.00198178 interval/scaled: 6238006 1.00002854 interval/sqrt(258)=6225728 approx :6250190 1.00392918 interval/scaled: 6225870 1.00002281 interval/sqrt(259)=6213697 approx :6250190 1.00587299 interval/scaled: 6213780 1.00001336 interval/sqrt(260)=6201736 approx :6250190 1.00781297 interval/scaled: 6201738 1.00000032 interval/sqrt(261)=6189844 approx :6250190 1.00974920 interval/scaled: 6189929 1.00001373 interval/sqrt(262)=6178020 approx :6250190 1.01168174 interval/scaled: 6178165 1.00002347 interval/sqrt(263)=6166264 approx :6250190 1.01361051 interval/scaled: 6166445 1.00002935 interval/sqrt(264)=6154574 approx :6250190 1.01553576 interval/scaled: 6154585 1.00000179 interval/sqrt(265)=6142951 approx :6250190 1.01745724 interval/scaled: 6142955 1.00000065 interval/sqrt(266)=6131393 approx :6250190 1.01937521 interval/scaled: 6131552 1.00002593 interval/sqrt(267)=6119900 approx :6250190 1.02128956 interval/scaled: 6120009 1.00001781 interval/sqrt(268)=6108472 approx :6250190 1.02320024 interval/scaled: 6108509 1.00000606 interval/sqrt(269)=6097107 approx :6250190 1.02510748 interval/scaled: 6097234 1.00002083 interval/sqrt(270)=6085806 approx :6250190 1.02701105 interval/scaled: 6085819 1.00000214 interval/sqrt(271)=6074567 approx :6250190 1.02891120 interval/scaled: 6074627 1.00000988 interval/sqrt(272)=6063390 approx :6250190 1.03080785 interval/scaled: 6063477 1.00001435 ... interval/sqrt(99999)=316229 approx :6250190 19.76475908 interval/scaled: 316236 1.00002214 > >