From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pl0-x236.google.com (mail-pl0-x236.google.com [IPv6:2607:f8b0:400e:c01::236]) (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 964BC3BA8E for ; Sun, 17 Jun 2018 20:59:05 -0400 (EDT) Received: by mail-pl0-x236.google.com with SMTP id t12-v6so8075420plo.7 for ; Sun, 17 Jun 2018 17:59:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-language:content-transfer-encoding; bh=p2h9D6C3CcGgqwA5pXh2lTNZYvmKu30Pw6boWvJTKUo=; b=GxGTzpDESXjeg021h1UosGXYy1nVUiupMEd41lplaJEAIasOToDL3N5ycIDe8fMBB8 y3a6xen6cFrtSbYK1NkTWb/hGJejwpd0BL8taMuZgpO4HuJvkBAZR0pFkCNufuQcD0w1 aL7atkbajcVvoPFG/rMWAzY5AQoBQ81oX7p1BlL9qlRdGc3K+1lYOjELTyHIPgC2Mu4x X1e9LBcNMGud7R/dW0kQGWgDRs+WX4B8gFisBCljZC8tAs9lx5221opzWzhYLygXj2fo 9vXIfRGjcemwb8HiHPvcd1WRxOL4PDnbYyWssGXyYaCRizv1WCketPN3YPVAfkB0KOLT FO8w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=p2h9D6C3CcGgqwA5pXh2lTNZYvmKu30Pw6boWvJTKUo=; b=CAC5ia8SwlvX6Y+Rdzl0SbUDzwz7eyej0X54uEfFrGH94mkWwdz0D9dM39XFFpi5qB zW31bmuZSyDRXo50CHhpun9P19iYmvNts6rzQT5r6NfWL4x/r+TS1Zdlcv8XXpFHk5JG 6MN4Qlia7WzoL+fTmBQOLTgTGKSGclXo8kQXJxbrbjW2PPXY+BV1f7YTD3B/zGtSk09r G9HpF+xz7gM8M4VhiP+WI0A+bIpq7CDnsoUy7x8qfUmcQ/9a4YveQhfCXMpL0/JpCb03 pqNq9Ftx5q0fsEktDs4qrt2/LN0TdOGYU5YOEAGo5Rauq6IRLYXwgekEUjWlhuQzAFZS g2rw== X-Gm-Message-State: APt69E1XXGpFaA250j/Wo1HKPf8z33KxYVTgcqBvd0Fh7SQwUQ+RR/Y8 pfkynve4FqyCaTxwE4w784M9+j/z X-Google-Smtp-Source: ADUXVKJ08ZG8d7oXhQ2K0dJdyt21FvACAKpJ3mZz/5wplKfuls0xQTJI+rPtLyU64F4razAnhpbRKA== X-Received: by 2002:a17:902:6105:: with SMTP id t5-v6mr11881894plj.138.1529283544721; Sun, 17 Jun 2018 17:59:04 -0700 (PDT) Received: from [192.168.86.235] (c-67-180-167-114.hsd1.ca.comcast.net. [67.180.167.114]) by smtp.gmail.com with ESMTPSA id a81-v6sm27072586pfl.167.2018.06.17.17.59.03 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 17 Jun 2018 17:59:03 -0700 (PDT) To: make-wifi-fast@lists.bufferbloat.net References: <1527721073.171416827@apps.rackspace.com> <150ABF21-FAFC-48E2-9E55-CAA609EAE449@heistp.net> From: Eric Dumazet Message-ID: <6800a688-b167-8bc7-0a47-13f38109e3a3@gmail.com> Date: Sun, 17 Jun 2018 17:59:02 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <150ABF21-FAFC-48E2-9E55-CAA609EAE449@heistp.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Make-wifi-fast] emulating wifi better - coupling qdiscs in netem? X-BeenThere: make-wifi-fast@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 18 Jun 2018 00:59:05 -0000 On 06/16/2018 03:53 PM, Pete Heist wrote: > The mean induced latency of 65us for C or 114us for Go might be within your parameters, except you mentioned 10us for WiFi bus arbitration, which does indeed look impossible with this setup, even in C. > You guys have to learn about busy polling, to avoid scheduler being in the picture. Basically, do not ever block in a system call, dedicate one thread/cpu for this netem stuff.