From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ssdrsserver2.hostinginterface.eu (mail-ssdrsserver2.hostinginterface.eu [185.185.85.90]) (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 77E8F3B29D for ; Sat, 26 Feb 2022 09:00:33 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=bobbriscoe.net; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:From:References:To:Subject:MIME-Version:Date:Message-ID:Sender: Reply-To:Cc:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=3tAFUDIzeFqerrHiJoHpV2NgrZFwa/FFmWAPQ8TAVbo=; b=kAzJBGwMl6e4x/lwdTf0pTVHFF NMZeWWNDqXKypJZig/pniPldhjzrR2v3GWgorbfjk4bYmSqCgCDpgb/9Kw1fyN4j0WXJWpajp99XP Uo0UlMwPeukBPLlPN1Nrr1zk79cVQPPZDU3wkluydVhrpZJy1ZbIg4kjJ/7NkLhMWQf3kIR61V16b KY0Sb5HNcr0rLN0kj8ZL6DpqLetz+IF1xv15ed58ofXawLr3vpzO5+Tgbb8ZEoIHIDhZlKVRskbSb J30YwYAkVfpU3P9m60bT9xH6MRuAm31bqYwkWs0YJZJFdzm84WAlD3i4Gj3Pfhzb9r4pVGtXRhUKJ csxYoC9Q==; Received: from 67.153.238.178.in-addr.arpa ([178.238.153.67]:55648 helo=[192.168.1.11]) by ssdrsserver2.hostinginterface.eu with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (Exim 4.94.2) (envelope-from ) id 1nNxcp-0002fw-8S; Sat, 26 Feb 2022 14:00:32 +0000 Message-ID: <141107c3-4e8b-ed3d-88a3-1df26fbe22d7@bobbriscoe.net> Date: Sat, 26 Feb 2022 14:00:31 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.5.0 Content-Language: en-GB To: Dave Taht , ECN-Sane References: From: Bob Briscoe In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - ssdrsserver2.hostinginterface.eu X-AntiAbuse: Original Domain - lists.bufferbloat.net X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - bobbriscoe.net X-Get-Message-Sender-Via: ssdrsserver2.hostinginterface.eu: authenticated_id: in@bobbriscoe.net X-Authenticated-Sender: ssdrsserver2.hostinginterface.eu: in@bobbriscoe.net X-Source: X-Source-Args: X-Source-Dir: Subject: Re: [Ecn-sane] for the record... X-BeenThere: ecn-sane@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Discussion of explicit congestion notification's impact on the Internet List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 26 Feb 2022 14:00:33 -0000 Dave, I'm replying on the SANE list where this question was posted, but this is not related to ECN - it's about bugs in the way CoDel recovers its dropping mode state. Pls move it to a more appropriate list if you want. See [BB] On 25/02/2022 21:22, Dave Taht wrote: > I don't understand the "immediately forgotten" part of this plot. For > pure non-ect traffic should have hit 50% drop and more or less stayed > there. With a mix of ect and non ect traffic we should have hit the > drop_batch facility a lot and never got to a right drop rate. > > https://l4steam.github.io/overload-results/ > [BB] Last Oct I wrote these slides, initially as a notepad for myself, to work out why 'count' was being forgotten when CoDel re-entered dropping mode.     https://bobbriscoe.net/projects/latency/CoDel-delta-bug.pdf I fixed the slides up a bit to try to make them understandable by others. And I've just added the last slide to put this bug in the context of the larger design flaw in the control law itself. I'm not saying my remedies to the bugs are necessarily correct, but at least the slides explain what the bugs are. I can't understand how no-one has noticed this bug before tho'. Bob -- ________________________________________________________________ Bob Briscoe http://bobbriscoe.net/