From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mout.gmx.net (mout.gmx.net [212.227.17.22]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 7F8533B29D; Sat, 26 Aug 2023 07:48:14 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1693050493; x=1693655293; i=moeller0@gmx.de; bh=uNFSfm/pBy5FsHbbq3rzdEkJqyf0Yf807JFGN7BIBrY=; h=X-UI-Sender-Class:From:Subject:Date:To; b=tcRRplO3wZ+1U383hcJnz55VaejG7NdApzu9D+lbb5uiSUxpjwh32q8lMSrbi3Jac4IhK7a fBoIXbTsTRmUvMq5cQtiYhzzkcuvo/3TewI3osr9CDxAeIruEYwIatJ+UUNEXeihKawJw+dbI XqOf1TRzk7gLf6+VeS1kZKNjg5gDqE2cJxeYrXWi9JF6VAHO0oaCdbJYdQRpIUG0n4OUOhLMx wcgrvSlhPXY8q/Sp8BzlP9/yHwz8JaFRHRXraOhFbczq+qfWqCKtwUbMTaDBi+atOJskoBKJf zYomfCDU5FMilq69k63l5tirSXdsU6RwGbha5t06c8pejnxplRUQ== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from smtpclient.apple ([77.1.16.9]) by mail.gmx.net (mrgmx105 [212.227.17.168]) with ESMTPSA (Nemesis) id 1N2E1G-1pZTwQ3tTa-013bgA; Sat, 26 Aug 2023 13:48:12 +0200 From: Sebastian Moeller Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3696.120.41.1.4\)) Message-Id: <553CF2FE-5A3C-4912-B367-4BF2C6A98D2A@gmx.de> Date: Sat, 26 Aug 2023 13:48:12 +0200 To: ECN-Sane , bloat X-Mailer: Apple Mail (2.3696.120.41.1.4) X-Provags-ID: V03:K1:840KItfPw/SbgbTX0J9c58Ri+1X3Ld9t5cGQsHFLcYJ/za4nLCW 0m6ULLZx6oJA0Fv2wRcV3QjzTnWR2SGJnsYx6lnLfW69onCDgbJ9tvzOIbeyG0OmkfL+D2Q 7sJrKCyyvo5RKOSYM5OKKunjMxbYIUJHL2clnGAId/mejORN5ctdm+ewEXxnK99WbcQgfAH dibO1OKRnXtHjKwgV16AQ== X-Spam-Flag: NO UI-OutboundReport: notjunk:1;M01:P0:YeUMt3P34K8=;93lUT/m2Kt11ECTZNWGZOoQCi/g 4DO2T1N4dhuQy/0HbZfoN3qQwGe8Dw6Gf0+dZUEUA8rV2Px4+pOkviHCnplPNx+x9EyYHAoRV 6Di2WX1kdGBbdOocBXxRxWNGucb1+ihPlxyhG+124o/A42ez3DRp+uZ3G0CeWk0QIxVUKuQTR xsgdkhwOP7wtmb8WkDdtMeZRdhRlgHOs1etccLfezJ1ijawb9qxhjMeKZDqLdG9llhIHklnwA AJqJIqMaPnxmC47KQF89jZR3o8WS8oWzKzOD2iQkomYPG3ljyEbyS0TczFjVSu0fP5v264MbK HleGUJ5oFfpqsajMh0LV6ORMUOs2+L833NuuCUk3M8/wMJ+P2RN3MY/K69AURzaf8nb6NXAA3 T80lpg5bhpjtREe1MX+Q8TDvjIRE92nLgGGJkp/D9BJmAqLKf1AXcghvgPE1dcAQ111SQdjkn 6cFjUR5YsB6mcVLIffDk2b1ETudbe278HE8IQAZ7Z/HLVvKDrFJIqfRnXbcGsyGK1PyDih3Pj tFhR4YPpmme4kTMVbQeRISyVmGQubNyIWSAvq7ZTD2x3N9JHmdAY0aDzZA1LAgY06hjJy5pef 83F1zEvrfgHVT2ikj+xZ6u2H98E8LpwBlZsaBYy8S6ObhxH6zdu6EqG4AXxpz9or0Av+fxR4I OcTVMQQuVkSsCOjv0GsGkCBtve2uP1WDhARJPhgqq4b5Niz9ltJPWxBWUhWAhKKvJCgem5qCq QwwoJZkYSHLBqYa30EJlrpJI23TKGcvay8zJzhkDfi83R+mKR/lpoBk27TJWlFgaZDWOKeK6Y keT5cZgueoSE3tT0OfkHUF7SHYfxXdHRqHZhDBHMYnWBUe+NwTE5QXjHKHH7lapkr62dDd+2H 0wJJRhEZIZNdMbRG+yXQVtqdb0nuS0bV1mJXhIKic0eqVo26qZzSKReL18v6NjM+E/izEDe5z Sl7RsQ== Subject: [Bloat] quick question X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 26 Aug 2023 11:48:14 -0000 Dear ECN-experts, I have a quick question, when running downloads, say x flows (with MTU = ~1500), over a Y Mbps link with Zms RTT, what kind of CE rate do I need = to expect? I ask, because the kids started to play some games on steam, and when = these do their multi-GB updates I accumulate quite a lot of CE marks for = the respective cake tin: Before: qdisc cake 810a: dev ifb4pppoe-wan root refcnt 2 bandwidth 105Mbit = diffserv3 dual-dsthost nat nowash ingress no-ack-filter split-gso rtt = 100ms noatm overhead 34 mpu 88 memlimit 32Mb=20 Sent 21471648426 bytes 16712159 pkt (dropped 9179, overlimits 27961170 = requeues 0)=20 backlog 2984b 2p requeues 0 memory used: 864Kb of 32Mb capacity estimate: 105Mbit min/max network layer size: 28 / 1492 min/max overhead-adjusted size: 88 / 1526 average network hdr offset: 0 Bulk Best Effort Voice thresh 6562Kbit 105Mbit 26250Kbit target 5ms 5ms 5ms interval 100ms 100ms 100ms pk_delay 116us 2.68ms 88us av_delay 31us 1.29ms 18us sp_delay 6us 57us 6us backlog 0b 2984b 0b pkts 170434 16500879 50027 bytes 73422115 21408109703 3480229 way_inds 56 1320752 2152 way_miss 3879 101928 341 way_cols 0 0 0 drops 12 9167 0 marks 34 559 0 ack_drop 0 0 0 sp_flows 1 5 1 bk_flows 0 1 0 un_flows 0 0 0 max_len 1492 1492 192 quantum 300 1514 801 After: qdisc cake 810a: dev ifb4pppoe-wan root refcnt 2 bandwidth 105Mbit = diffserv3 dual-dsthost nat nowash ingress no-ack-filter split-gso rtt = 100ms noatm overhead 34 mpu 88 memlimit 32Mb=20 Sent 26301367224 bytes 19973069 pkt (dropped 9381, overlimits 34351737 = requeues 0)=20 backlog 0b 0p requeues 0 memory used: 1025408b of 32Mb capacity estimate: 105Mbit min/max network layer size: 28 / 1492 min/max overhead-adjusted size: 88 / 1526 average network hdr offset: 0 Bulk Best Effort Voice thresh 6562Kbit 105Mbit 26250Kbit target 5ms 5ms 5ms interval 100ms 100ms 100ms pk_delay 336us 238us 180us av_delay 62us 96us 36us sp_delay 2us 2us 8us backlog 0b 0b 0b pkts 171622 19760656 50172 bytes 73494415 26237802841 3493005 way_inds 56 1321363 2237 way_miss 3904 102830 345 way_cols 0 0 0 drops 12 9369 0 marks 34 2346888 0 ack_drop 0 0 0 sp_flows 1 19 1 bk_flows 0 1 0 un_flows 0 0 0 max_len 1492 1492 192 quantum 300 1514 801 # note there was other traffic ongoing as well, so some drops/marks are = unrelated, but the bulk of marks was correlated with the steam download delta packets: (19760656 - 16500879) =3D 3259777 delta bytes: (26237802841 - 21408109703) / 1000^3 =3D 4.829693138 GB average packet size: (26237802841 - 21408109703) / (19760656 - 16500879) = =3D 1481.60231145 delta drops: (9369 - 9167) =3D 202 delta marks: (2346888 - 559) =3D 2346329 fraction of packets marked: 2346329 / 3259777 =3D 0.719782058711 percentage of packets marked: 100 * (2346329 / 3259777) =3D 72% This seems like too high a marking rate to me. I would naively expect = that a flow on getting a mark scale back by its cwin by 20-50% and then = slowly increaer it again, so I expect the actual marking rate to be = considerably below 50% per flow... My gut feeling is that these steam flows do not obey RFC3168 ECN (or = something wipes the CE marks my router sends upstream along the path)... = but without a good model what marking rate I should expect this is very = hand-wavy, so if anybody could help me out with an easy derivation of = the expected average marking rate I would be grateful. Regards Sebastian