From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-x233.google.com (mail-pg0-x233.google.com [IPv6:2607:f8b0:400e:c05::233]) (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 CC5133B2A4 for ; Fri, 14 Apr 2017 14:00:46 -0400 (EDT) Received: by mail-pg0-x233.google.com with SMTP id 21so46253856pgg.1 for ; Fri, 14 Apr 2017 11:00:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=message-id:subject:from:to:cc:date:in-reply-to:references :mime-version:content-transfer-encoding; bh=djTPvUP8jiA3vpP0riQx8oSOvqvpVqnSoL37iJfJiOE=; b=fHO7fNKRPGQ3m67lrSpJ56PkYL0dQ7XjOyW2UUniFdUmxdbYcq43nU/P2WtC9EbxOR ix2uAneRaoKcTNpfnpBgQ44De3Cm0ZhzA6PFeVdtPGO6TMaheCEbUHbCRv5RciMVOjOc HgERgA5juhxMamgHteg+q06Gc3XXZJMkoYWOr2gqnhzDyDM5pRmfM9KSrJHSKpcJbd2/ Wd8OKdAA4tC+1IggaRHXNNQTUs5sW7QUC5IOiOdSs46fRhvxu8qNUEAS4nH/+xlH63hp r2OV0bTO7YWjd46dqVyPGRhaLoqvSFkaPTIoJOoy8PTbT423qZXZGs28W4/rwMru4Rgw 0niQ== 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:mime-version:content-transfer-encoding; bh=djTPvUP8jiA3vpP0riQx8oSOvqvpVqnSoL37iJfJiOE=; b=orP5p7JdUhx5BQF3fyi58qATbwb7CuoFg4SmPnRqCg99Dsm8ucRmiObFeCzGIKrw89 YrsPybWpuUzP1mO1M7rWB/PxguEfVsx0eiCZeiRRU2Rtg5s6RrdhDtNOjvG3NbwEIKQy 94B9Y2HtPXHulV3r65IthuWUS18htbeGcjkkQ04+aMQMIgXf4aRPZph9dzlOx7spnYv2 xBZji7lSwj00XFA/NU4Rsb6DqyTIOdcl9OaXzlHcYJVITQZa8v3PSXshZ7M2FhOGvMa/ 0Z1mn9XhgOVmUm7opeKTgO2NHy1R11gXsMWLm12umguVhmMPw8vj8cOWoag1O4m5wakO O5Ow== X-Gm-Message-State: AN3rC/7VzUAxTSyYSFl7p3bqRL4jJf37qjVeUkAkxuX8Su/SoiYMCV4N PK3/3/Rt7akKcA== X-Received: by 10.98.28.193 with SMTP id c184mr8188020pfc.212.1492192846010; Fri, 14 Apr 2017 11:00:46 -0700 (PDT) Received: from ?IPv6:2620:0:1000:1704:4428:8e64:dc3:7322? ([2620:0:1000:1704:4428:8e64:dc3:7322]) by smtp.googlemail.com with ESMTPSA id 202sm4446506pfz.36.2017.04.14.11.00.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 14 Apr 2017 11:00:44 -0700 (PDT) Message-ID: <1492192844.10587.78.camel@edumazet-glaptop3.roam.corp.google.com> From: Eric Dumazet To: Aaron Wood Cc: bloat Date: Fri, 14 Apr 2017 11:00:44 -0700 In-Reply-To: References: Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: Re: [Bloat] sch_fq pacing rate: Xbps, but at which layer in the network stack? 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: Fri, 14 Apr 2017 18:00:47 -0000 On Thu, 2017-04-13 at 20:12 -0700, Aaron Wood wrote: > When I was testing with my iPerf changes, I realized that the sch_fq > pacing (which in iperf is set via setsockopt()), is pacing at a > bandwidth that's set at a pretty low level in the stack (which makes > sense). This is different from the application pacing that iperf does > (which is pacing the goodput). > > > But it's not clear to me where the X bps determination is being made. > My current guess is that it's at the interface level (since that's > where sch_fq is), and so it's approximately "bytes on the wire", minus > preambles and inter-packet spacing, and whatnot. And so it's > including all the 802.x headers involved (vlan tags, qos tags, > source/dest macs, etc). Is this correct? > Like other qdisc having rate limits (TBF, HTB ....), FQ sees packets with all headers (including Ethernet one) This is why the default quantum is 3028, which is exactly 2 regular Ethernet frames (MTU=1500 + 14 bytes of Ethernet header) If you have VLAN tag, it is generally not included in the calculation, as many devices provide 'hardware tagging'.