From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-x22c.google.com (mail-it0-x22c.google.com [IPv6:2607:f8b0:4001:c0b::22c]) (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 B59E63B29E for ; Tue, 17 Apr 2018 09:16:05 -0400 (EDT) Received: by mail-it0-x22c.google.com with SMTP id 71-v6so16116736ith.2 for ; Tue, 17 Apr 2018 06:16:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=dTGJ0Hbln+0e8VB2UEM428BRXHJeQX2yEgCwgZrLd6I=; b=fyxbeMyHvjS+Y/MJjLZjkD8P2ZrDcSJwskfW4aBWoRjpqPSdLiwR4kta6f3Aa8M+nq TDGMP/8e3vn1YZAtsLIN1K9rc3OqOkKPzNevNRCM4EjqiI8W+UYUYWz+yNJ4kqpbKLPv vJ/NO168zBSA3roVtp6vlkXplBRiqZ9QtkncxUxfSjkGW3uCJ92/ESGak8c0LdXXoUKH ayNjnh1sknmLc5x7y49PXWqdqFCmtsu+cNMe9q/AxIjlvLKQcPZxsTtLw0Wnd3sQNqH6 aefeXqfj3uyEY19gQo+gNIV/tpU9Bs+9HzEG42pq4lyHbVM/W6syos5yV3A5s4NBRkJu qTag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=dTGJ0Hbln+0e8VB2UEM428BRXHJeQX2yEgCwgZrLd6I=; b=a3yDKGtmy4YGL2rtQJKY7FyKS9gxNzw+wYAzEXpSOg+Kaa6V4QWKqvfZDV2BoW0fz1 S8AjaFZG+B7wnzGg/8kEgE1pWEIM1PXB5Qpr4IIM9NSxXtkSgL1acvQ5w9nJMrtKjnW/ NWjrj7P0eZxCpDGopRs2sTpK3B0YaCiCj7feM42j2p3xCdlHre2t/+JluItjcxQ2C1qb NBWaCKgmHr7DXQ27O9b5qj133+dstakl9//E8TivQ3ZTGNRshnd6Dpd3/YUe4VMc7Q4C Hw67o3HATOfz/6FpWm3KL4zNs4aoL8qvDiP2h28SILxDpFsf43VNYvu+7wnJAB7H9DTU SlZA== X-Gm-Message-State: ALQs6tDbVDh6IM6I+sJ2ziJdSfQ/slWARnliLVYE6hCuyMhn98ZRBBAO HA1RAOiHaPoOZCLA8VJhCtVYUxmiAGVPmxAKxIg= X-Google-Smtp-Source: AIpwx4+A3XtFno6DB7IA17BLUuwFrHofJsqxMTfOggeLFb2IBKCpsu+NUJsvGafFGa5kC3BxH5Ic3c9WNBic4DS1GBQ= X-Received: by 2002:a24:7385:: with SMTP id y127-v6mr1206628itb.10.1523970965151; Tue, 17 Apr 2018 06:16:05 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:6c85:0:0:0:0:0 with HTTP; Tue, 17 Apr 2018 06:16:04 -0700 (PDT) In-Reply-To: <87muy23tvg.fsf@toke.dk> References: <87vacq419h.fsf@toke.dk> <87sh7u3yoa.fsf@toke.dk> <87muy23tvg.fsf@toke.dk> From: =?UTF-8?Q?Jonas_M=C3=A5rtensson?= Date: Tue, 17 Apr 2018 15:16:04 +0200 Message-ID: To: =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= Cc: Y , Cake List Content-Type: multipart/alternative; boundary="00000000000006b1a0056a0b245b" Subject: Re: [Cake] A few puzzling Cake results X-BeenThere: cake@lists.bufferbloat.net X-Mailman-Version: 2.1.20 Precedence: list List-Id: Cake - FQ_codel the next generation List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 17 Apr 2018 13:16:05 -0000 --00000000000006b1a0056a0b245b Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, Apr 17, 2018 at 2:22 PM, Toke H=C3=B8iland-J=C3=B8rgensen wrote: > Y via Cake writes: > > > From: Y > > Subject: Re: [Cake] A few puzzling Cake results > > To: cake@lists.bufferbloat.net > > Date: Tue, 17 Apr 2018 21:05:12 +0900 > > > > Hi. > > > > Any certain fomula of fq_codel flow number? > > Well, given N active bulk flows with packet size L, and assuming the > quantum Q=3DL (which is the default for FQ-CoDel at full-size 1500-byte > packets), the maximum rate for a sparse flow, R_s, is bounded by > > R_s < R / ((L/L_s)(N+1)) > > Where R is the link rate and L_s is the packet size of the sparse flow. > This assumes that the sparse flow has constant spacing between its > packets, which is often the case for a VoIP flow... For 10-Mbit/s link rate and 32 bulk flows with 1500-byte packets this formula gives roughly 25 pps (packets per second) as maximum for a sparse flow. A VoIP flow is typically 50 pps (20 ms voice payload). Does this mean that cake sets the quantum to less than 750 bytes for a 10-Mbit/s link? Do you see any benefit with cake diffserv if you increase the number of flows? Does the adjusted quantum also explain the "*way* higher" TCP RTT for cake? How? /Jonas --00000000000006b1a0056a0b245b Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable


On Tue, Apr 17, 2018 at 2:22 PM, Toke H=C3=B8iland-J=C3=B8rgensen <toke@tok= e.dk> wrote:
Y via Cake <cake@list= s.bufferbloat.net> writes:

> From: Y <intruder_tkyf@ya= hoo.fr>
> Subject: Re: [Cake] A few puzzling Cake results
> To: cake@lists.bufferblo= at.net
> Date: Tue, 17 Apr 2018 21:05:12 +0900
>
> Hi.
>
> Any certain fomula of fq_codel flow number?

Well, given N active bulk flows with packet size L, and assuming the
quantum Q=3DL (which is the default for FQ-CoDel at full-size 1500-byte
packets), the maximum rate for a sparse flow, R_s, is bounded by

R_s < R / ((L/L_s)(N+1))

Where R is the link rate and L_s is the packet size of the sparse flow.
This assumes that the sparse flow has constant spacing between its
packets, which is often the case for a VoIP flow...

For 10-Mbit/s link rate and 32 bulk flows with 1500-byte packets t= his formula gives roughly 25 pps (packets per second) as maximum for a spar= se flow. A VoIP flow is typically 50 pps (20 ms voice payload).
<= br>
Does this mean that cake sets the quantum to less than 750 by= tes for a 10-Mbit/s link?

Do you see any benefit w= ith cake diffserv if you increase the number of flows?

=
Does the adjusted quantum also explain the "*way* higher" TC= P RTT for cake? How?

/Jonas

<= /div> --00000000000006b1a0056a0b245b--