From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.15.19]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-1" (verified OK)) by huchra.bufferbloat.net (Postfix) with ESMTPS id F14DC21F9AA for ; Tue, 29 Sep 2015 08:35:10 -0700 (PDT) Received: from [134.2.89.70] ([134.2.89.70]) by mail.gmx.com (mrgmx002) with ESMTPSA (Nemesis) id 0MSv6D-1a8kgA3Akn-00Rtfy for ; Tue, 29 Sep 2015 17:35:07 +0200 From: Sebastian Moeller Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Message-Id: <9759FDF8-C718-42D0-B1C8-1F817DBA208E@gmx.de> Date: Tue, 29 Sep 2015 17:35:03 +0200 To: cake@lists.bufferbloat.net Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) X-Mailer: Apple Mail (2.1878.6) X-Provags-ID: V03:K0:FtSu+t6llIFR5bGdwM3WDb3NLojYLtSb0ft0i+IQGGL2FtjINOm 2Y2CikEZZh4VDcXVkyCnuWHEFaJfILyMYHF11MJSBY9Xn1nhT8YNI6p7QUdRQD+7oHwuGuq SC7u8ZJo/3VQa/yXSZo4EkfP6clkvNsL8RtSK3ykS2ytOQGowEA34mCAxvspvVv/UH7iLBG yXVY0N0G+5GcQzDXjlJhg== X-UI-Out-Filterresults: notjunk:1;V01:K0:Kq9SZ4Ozjqo=:kUWIC0IRYNYyiez5m2znyp UxOO0o5lPblFcAy9TCJsOuGkursZ0VD6TWpn4c9pZw6ICLtu98YQvjmk2z4c+vSBm436mNo3V TkBm6/51l+bfXeqBhFckaeduraBwKqlksE0vHiVfTh3eBtlSHUc2rGxQflPFkRifpngautSEz yAX1+09f6s+/T1WQox2wZ8a7UuOCXdRF7u4R0wMap/gsDyGYBzZtUW28RkzD5XGAI0bw8gyuW nqCkre/vsd/PShmEUlgtPwqvla2Rxw+KIGvK58O/+UdtESEZ7fOmkrSu8UYxgQlOC/zzCWON5 L7dmbXgu+mQOY84Ev2Ew4YSeGoawkKw6q0UIQTExpka0mdZD7jda5tDKMAqKEfEmOmxwpc+M+ iLy6oUZRTALWcEJQD0JoyQi3cABXcARGauFOatdyBzTcU2thu2xKIXYdnpwhGJq0tID8okdaI CGEm/yRDzQ68pWMI+hc8NwJFe4QVyS2nxyY8gF3p/ra8IPFsqQjX0N4QEFt7UN0ARQt110aVP 44z7DOMO76oA8wCyEQLfJkiT+KOQx8bX4YtuIcQOUD9xcKOcqsKXsb3/xP1Pkw/myKkgB7oLN z8zMdZNpad3DovOEM7yPDHU989RAkZ6nNwW93j5nF5xTTJAvvMFBmPGbhANn0Y3aViQ87abz9 3oxmWFeN7nMgMFWmTG7wKrowJ/ujWYFcGWsnmVcuCCsQIWCaNhln874LQeYQ5x+f0ljeCAqvt Ju9XLm6RXQMQ/6J9ekmxlUiDeFUfY03R/GbrHA== Subject: [Cake] statistics question? X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 29 Sep 2015 15:35:33 -0000 Hi list, I just played around with cake a bit and noticed that some of statistics = are odd: # reset all counters: user@computer:~/CODE/sch_cake> sudo tc-adv qdisc replace dev eth0 root = pfifo_fast # create a slightly silly, but permissible cake configuration: user@computer:~/CODE/sch_cake> sudo tc-adv qdisc replace dev eth0 root = cake diffserv8 atm overhead 100 # send some data in one of the higher class/bins (class 4) and look at = the results: user@computer:~/CODE/sch_cake> sudo ping -c 1 -s 16 -Q 4 gstatic.com ; = sudo tc-adv -s qdisc PING gstatic.com (173.194.112.215) 16(44) bytes of data. 24 bytes from fra02s17-in-f23.1e100.net (173.194.112.215): icmp_seq=3D1 = ttl=3D57 time=3D18.6 ms --- gstatic.com ping statistics --- 1 packets transmitted, 1 received, 0% packet loss, time 0ms rtt min/avg/max/mdev =3D 18.685/18.685/18.685/0.000 ms qdisc cake 801f: dev eth0 root refcnt 6 unlimited diffserv8 flows atm = overhead 100=20 Sent 2753 bytes 20 pkt (dropped 0, overlimits 0 requeues 0)=20 backlog 0b 0p requeues 0=20 Class 0 Class 1 Class 2 Class 3 Class 4 = Class 5 Class 6 Class 7 =20 rate 0bit 0bit 0bit 0bit 0bit = 0bit 0bit 0bit target 5.0ms 5.0ms 5.0ms 5.0ms 5.0ms = 5.0ms 5.0ms 5.0ms interval 100.0ms 100.0ms 100.0ms 100.0ms 100.0ms = 100.0ms 100.0ms 100.0ms Pk delay 0us 0us 0us 0us 0us = 0us 0us 0us Av delay 0us 0us 0us 0us 0us = 0us 0us 0us Sp delay 0us 0us 0us 0us 0us = 0us 0us 0us pkts 0 0 19 0 0 = 1 0 0 way inds 0 0 0 0 0 = 0 0 0 way miss 0 0 9 0 0 = 1 0 0 way cols 0 0 0 0 0 = 0 0 0 bytes 0 0 2695 0 0 = 58 0 0 drops 0 0 0 0 0 = 0 0 0 marks 0 0 0 0 0 = 0 0 0 qdisc fq 8009: dev ifb00 root refcnt 2 limit 10000p flow_limit 100p = buckets 1024 quantum 3028 initial_quantum 15140=20 Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)=20 backlog 0b 0p requeues 0=20 0 flows (0 inactive, 0 throttled) 0 gc, 0 highprio, 0 throttled user@computer:~/CODE/sch_cake>=20 Note how Class 4 reports one packet with 58 bytes? I am not sure what to = make out of this as: ICMP payload 16 bytes ICMP header 8 bytes IPv4 header 20 byte : Sum =3D = 44 bytes So 58 - 44=3D 14 or what the kernel considers to be the cost of an = ethernet packet (but that should actually include preamble, frame check = sequence and inter frame gap, but I digress). But I had told cake to add 100 bytes of extra overhead (and keep the = ethernet overhead) so at least I would have assumed 158 bytes, but since = I also specified atm the size should have been ceil(158/48)*53 =3D ceil(3.29166666667) * 53 =3D 4*53 =3D 212bytes. So clearly cake reports the size of packets as they are passed into it = from the kernel and not the (virtual) size as it sends them out, which = should be documented somewhere? Best Regards Sebastian