From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x32d.google.com (mail-wm1-x32d.google.com [IPv6:2a00:1450:4864:20::32d]) (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 6C0883B2A4 for ; Wed, 10 Mar 2021 03:22:27 -0500 (EST) Received: by mail-wm1-x32d.google.com with SMTP id m20-20020a7bcb940000b029010cab7e5a9fso10323830wmi.3 for ; Wed, 10 Mar 2021 00:22:27 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heistp.net; s=google; h=message-id:subject:from:to:cc:date:in-reply-to:references :user-agent:mime-version:content-transfer-encoding; bh=phptQ69rNDsEUMiHPf+Y659aAFvIuqHCubei/pQdnt8=; b=GavCdRT0JSXNuQH/8QLlk8W9jpNXlnB5A1LwxugDaH1EXxgxbngEZokHw8Zo8mBl86 Khr/SxzxerCM6Yg/ouAqLCNLbVzO+cBtLHxWqX+xvVm9/wllz1vXtcExKNUOQKqwEqpr 5LkcNIUbrC76g55roofiZiC7Jk73l84ZDgSgm0C/+HbFqZUJkksd4Xo6pUnx+FPfkjGN itOY2F36lLOEHAIM+x7+9jZAeUBAnU5DtL3GTXzBsI9hlK/NnX/BRBtxBbtgV2omSSJU eY3c+KUQkwamZ85Hj754fdTghv9bSIOtlZXnmQXjfH3QVmLRR7WSmHLwWeZQLKC1W1qZ PNfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:message-id:subject:from:to:cc:date:in-reply-to :references:user-agent:mime-version:content-transfer-encoding; bh=phptQ69rNDsEUMiHPf+Y659aAFvIuqHCubei/pQdnt8=; b=ugNf1NoW6guctCtN8tvQAMljen7rTGia5Vs4DGPpC++QlX5cWfUrmDKy/7uZbGZitJ 8w7JNnhe3a2dO7+b34yLqpPOWciCKfizm5WIIgL2nfVhhaMmanvlDTvG2Cq5FGomssJD nzkzD2DXmLwYbx/qwYSNyxqF6fIS6xztSUlKSX7PP6g0QR4tfODFnGHTctR4LlzLFa0K JpRa57iajXMLZW/3ota1ARjYVw8D3Lii1sqF+mgioK0WFdRewWSvTvqaUJQKiGAQyk9x WGvnkC55xI3yLBoJORsQGg4M/R9GAJBN3/uNPdQ2b6SjUqbfBR5YIco3c082yz0Cc0lf JIUA== X-Gm-Message-State: AOAM5321IQtfb1zqng8NhIjmKK9EMz1+HfRUc48LoyCD6vUjTa/a/D+z vT0ULgSqIOWTranDYQw3Iu2+/w== X-Google-Smtp-Source: ABdhPJyz5E2WLMYIhzazATCyMNrW/swSl6gyv+PVZeR0SLoE8h7RSCWksrfhzvUXZRVsd/Sw0VBu2A== X-Received: by 2002:a1c:c206:: with SMTP id s6mr2066508wmf.77.1615364546518; Wed, 10 Mar 2021 00:22:26 -0800 (PST) Received: from [10.72.0.88] (h-1169.lbcfree.net. [185.193.85.130]) by smtp.gmail.com with ESMTPSA id i10sm26377519wrs.11.2021.03.10.00.22.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 Mar 2021 00:22:26 -0800 (PST) Message-ID: From: Pete Heist To: Dave Taht Cc: ECN-Sane Date: Wed, 10 Mar 2021 09:22:25 +0100 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.38.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Ecn-sane] SCE pacing (was: a data point on syn and dscp) 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: Wed, 10 Mar 2021 08:22:27 -0000 Not sure if this covers it, but there was a brief time before we had enabled pacing programmatically in our TCP CCAs. There's a sysctl with default: net.ipv4.tcp_sce_pacing = 1 and in each CCA: if (sock_net(sk)->ipv4.sysctl_tcp_sce_pacing) cmpxchg(&sk->sk_pacing_status, SK_PACING_NONE, SK_PACING_NEEDED); This should enable the internal pacing mechanism in the kernel, which is different from the one used by the fq qdisc, iirc. On Tue, 2021-03-09 at 10:58 -0800, Dave Taht wrote: > > this leads to my final question in that early sce and l4s experiments > did have a lot of trouble with having to pace the initial burst, and I > don't know what is actually done there, now, in current oses. >