From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk1-x72b.google.com (mail-qk1-x72b.google.com [IPv6:2607:f8b0:4864:20::72b]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.bufferbloat.net (Postfix) with ESMTPS id 6BA4A3BA8E for ; Fri, 7 Sep 2018 03:17:56 -0400 (EDT) Received: by mail-qk1-x72b.google.com with SMTP id c126-v6so9109539qkd.7 for ; Fri, 07 Sep 2018 00:17:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=SaH9cCGiHwjbJ29rZdpMpmIxOLRE1EO/1QNUD4UERCg=; b=sij8mrOWu+lmb9H0ZycnTUUBlPuzIUQHiAJxCALGoX9z5k5oIgyKniwIKBeAABgZcZ frO0srp7inLfOBxzgwAfWL0n+Azi8b25dk0zV44e70gs2CMmknloPqFAWnPXFNyOLG+b kvlZ1fmoqNYHSIgMz+2ATZXWKH3ttGlKt5Gz1sHPszYDlRQ9HioolTLTzmmSkFSNgFD0 0NzZENbYyiEjhlYU4bONpE8dfHDElvEJ79cwA0Jn7Ov2p8K5vZR0Bc+sDKxqZxoH8z4W 2KCSHV38XYwSdDvSKAbOZPtflKTkzI0MtmYnSdfbjggwU3LafTHTRkSeKPySBBLaRB5V rpxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:from:date:message-id:subject:to :content-transfer-encoding; bh=SaH9cCGiHwjbJ29rZdpMpmIxOLRE1EO/1QNUD4UERCg=; b=M6koojkDeTA6mO7LQ+MGio0U3H3+8R+/HKsp1VIOJRtzMasH2EtTC5FiYh6m3RFx3F z2KCt8Gxw98/LlPhKDSDxNc86Nzhcz+U33eoXeR5dIt+094n2On6NDbPBotKNtdVNzpg mXEKWSPrZWz91OwHyiOh9MucY7aJu8VBNa0YX5l51GDaXbOkNWbfvxLkcI+XGhh+x8Hc STPea30FSFHiXfif6hZ9wRTNtrKwCN4zw5Lom2Ej/w3KlOmQkbf3avjD/6P3OMW9QJNM ypYnUY88Tthb59mtpWroDix43rtkD9hCY4O6wBM4D9+sgxPYbc/9K67sWi2s11c/D48q n0zQ== X-Gm-Message-State: APzg51AswiU52h/fQ8CAEQSITitu/tfZYhl+PK7yQOJ6ltmlozOPGanx xXyHXcnf0EBWT4/SOHUSyuyCLDsERr/BA5lcEFOywQ== X-Google-Smtp-Source: ANB0VdbDGxfdB44S0uR0rwMevYVxQHHQ+fDGWJ6UjNzJ2u7nxe9kV10IF/oaEPOfAPLqEeiHtm5zHjUHpb4HJSZW9vM= X-Received: by 2002:a37:b546:: with SMTP id e67-v6mr4909985qkf.237.1536304675472; Fri, 07 Sep 2018 00:17:55 -0700 (PDT) MIME-Version: 1.0 From: Dave Taht Date: Fri, 7 Sep 2018 00:18:48 -0700 Message-ID: To: ecn-sane@lists.bufferbloat.net Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Subject: [Ecn-sane] cwnd/2 - 1 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: Fri, 07 Sep 2018 07:17:56 -0000 One of the things that went by in recent kernel changes was that linux tcp at a cwnd 2 on a CE goes into quickack mode, so that we get back one ack per packet (I think, from reading the commit) instead of every other one. halving cwnd and then taking off 1 more gives a response that drops the mass closer along the lines of what a drop may do in response to loss and re-ordering. A cwnd 1 in quickack mode would halve the number of packets outstanding in my 100 flows test. I think. another thing to note is that retransmits, are, by the standard, and in linux, not protected by ECT, and when you get near to 100% mark rate as i do in this artificial test, get dropped a lot. --=20 Dave T=C3=A4ht CEO, TekLibre, LLC http://www.teklibre.com Tel: 1-669-226-2619