From: "Toke Høiland-Jørgensen" <toke@toke.dk>
To: Luca Muscariello <luca.muscariello@gmail.com>
Cc: Y <intruder_tkyf@yahoo.fr>, Cake List <cake@lists.bufferbloat.net>
Subject: Re: [Cake] A few puzzling Cake results
Date: Tue, 17 Apr 2018 17:10:44 +0200 [thread overview]
Message-ID: <87sh7t3m2z.fsf@toke.dk> (raw)
In-Reply-To: <CAHx=1M6R=2LzNb+TbKfq-czptoFUf6yHPWp0435s23NnAov4YQ@mail.gmail.com>
Luca Muscariello <luca.muscariello@gmail.com> writes:
> I will check that later, still unsure.
>
> First guess: the quantum component should influence only how close to a
> fluid bit-wise approximation you are.
> So cake gets closer by automatic adjustment.
>
> The computation of the correction factor should be done by computing the
> probability that a packet
> of a sparse flow loses priority because of the quantum. Bad setting, higher
> probability, ideal setting 0 probability.
>
> So your formula seems still wrong to me...
The formula expresses the conditions under which a flow is guaranteed to
be treated as sparse by the scheduler, under some quite strong
assumptions (most notably that the sparse flow is sending packets at a
fixed rate).
It's derived from the fact that when a packet from the sparse flow
arrives, it (in the worst case) has to wait for the bulk flow packet
that just started getting service (i.e., wait for L/R), after which the
sparse flow itself will get service (in time L_s/R), then it will have
to wait for its queue to pass through a whole round of scheduling (LN/R)
before it can get service as a sparse flow again. Adding these together,
the inter-arrival time between sparse flow packets has to be greater
then (L(N+1)+L_s)/R, which when converted to a rate gives the formula I
mentioned.
You are right, of course, that in the general case it will be different;
but I was talking about the specific case of the fixed-rate sparse flow
here... :)
-Toke
next prev parent reply other threads:[~2018-04-17 15:10 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-17 9:42 Toke Høiland-Jørgensen
2018-04-17 10:04 ` Luca Muscariello
2018-04-17 10:38 ` Toke Høiland-Jørgensen
2018-04-17 12:05 ` Y
[not found] ` <mailman.225.1523966725.3573.cake@lists.bufferbloat.net>
2018-04-17 12:22 ` Toke Høiland-Jørgensen
2018-04-17 13:16 ` Jonas Mårtensson
2018-04-17 13:50 ` Toke Høiland-Jørgensen
2018-04-17 13:47 ` Luca Muscariello
2018-04-17 13:52 ` Luca Muscariello
2018-04-17 14:25 ` Toke Høiland-Jørgensen
2018-04-17 14:54 ` Luca Muscariello
2018-04-17 15:10 ` Toke Høiland-Jørgensen [this message]
2018-04-17 14:03 ` Jonathan Morton
2018-04-17 14:17 ` Toke Høiland-Jørgensen
2018-04-18 11:25 ` Toke Høiland-Jørgensen
2018-04-18 12:21 ` Kevin Darbyshire-Bryant
2018-04-18 12:57 ` Toke Høiland-Jørgensen
2018-04-18 13:13 ` Jonas Mårtensson
2018-04-18 13:21 ` Toke Høiland-Jørgensen
2018-04-18 14:12 ` Jonathan Morton
2018-04-18 14:30 ` Toke Høiland-Jørgensen
2018-04-18 15:03 ` Jonathan Morton
2018-04-18 15:17 ` Sebastian Moeller
2018-04-18 15:58 ` Jonathan Morton
2018-04-18 16:11 ` Toke Høiland-Jørgensen
2018-04-18 16:25 ` Dave Taht
2018-04-18 16:34 ` Georgios Amanakis
2018-04-18 17:10 ` Sebastian Moeller
2018-04-19 7:49 ` Luca Muscariello
2018-04-19 8:11 ` Jonathan Morton
2018-04-19 9:00 ` Toke Høiland-Jørgensen
2018-04-19 9:21 ` Jonathan Morton
2018-04-19 9:26 ` Toke Høiland-Jørgensen
2018-04-19 9:55 ` Jonathan Morton
2018-04-19 10:33 ` Toke Høiland-Jørgensen
2018-04-19 11:55 ` Luca Muscariello
2018-04-18 16:54 ` Jonathan Morton
2018-04-18 17:02 ` Dave Taht
2018-04-18 18:06 ` Jonas Mårtensson
2018-04-18 18:11 ` Toke Høiland-Jørgensen
2018-04-18 18:16 ` Kevin Darbyshire-Bryant
[not found] ` <mailman.238.1524075384.3573.cake@lists.bufferbloat.net>
2018-04-19 8:31 ` Kevin Darbyshire-Bryant
2018-04-18 18:11 ` Jonas Mårtensson
2018-04-18 19:53 ` David Lang
2018-04-18 21:53 ` Jonathan Morton
2018-04-19 9:22 ` Toke Høiland-Jørgensen
2018-04-19 9:32 ` Jonathan Morton
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