Cake - FQ_codel the next generation
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From: Pete Heist <peteheist@gmail.com>
To: Jonathan Morton <chromatix99@gmail.com>
Cc: cake@lists.bufferbloat.net
Subject: Re: [Cake] Cake latency update
Date: Fri, 10 Feb 2017 10:21:35 +0100	[thread overview]
Message-ID: <652AA7A2-60C5-460F-AE60-CF4CB1D1D781@gmail.com> (raw)
In-Reply-To: <B1561380-3DB9-4A11-AEA5-6775562A8971@gmail.com>

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> On Feb 10, 2017, at 9:49 AM, Jonathan Morton <chromatix99@gmail.com> wrote:
> 
> 
>> On 10 Feb, 2017, at 10:04, Pete Heist <peteheist@gmail.com> wrote:
>> 
>> I look forward to the throughput shifts being solved, where I see results like this:
>> 
>> http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_100ms_80mbit/index.html
> 
> That basically looks like it’s run out of CPU, so there’s hard choices to make over CPU allocation.  Cake isn’t responsible for that allocation, though it *might* be possible to optimise its use of the CPU a little further.
> 
> If you can obtain a CPU profile of that workload on that hardware, that might help to direct those efforts.
> 
> - Jonathan Morton

I’d be surprised if that were a CPU problem in this case, as that test was run with Cake on a 2.4 GHz Core 2 Duo, not so new, but far more powerful than a typical embedded CPU. Here’s the CPU info:

http://www.drhleny.cz/bufferbloat/hostinfo/mbp_cpuinfo.txt <http://www.drhleny.cz/bufferbloat/hostinfo/mbp_cpuinfo.txt>

Here are the results at various bitrates (all half-duplex rate limiting on this CPU). I find it easiest to just open them in multiple browser tabs and keyboard shift between them to compare:

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_10mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_10mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_20mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_20mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_30mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_30mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_40mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_40mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_50mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_50mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_60mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_60mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_70mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_70mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_75mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_75mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_80mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_80mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_85mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_85mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_90mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_90mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_100mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth-ap_100mbit/index.html>

There are strange shifts at 30 Mbit, 40 Mbit and 70 Mbit, but I think this hardware should be able to handle those speeds. It’s interesting that the throughput shifts don’t seem to affect the latency.

Compare that to the results for HTB+fq_codel, which doesn’t show such shifts:

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_10mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_10mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_20mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_20mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_30mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_30mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_40mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_40mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_50mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_50mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_60mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_60mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_70mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_70mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_75mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_75mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_80mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_80mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_85mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_85mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_90mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_90mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_100mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth-ap_100mbit/index.html>

But if you still think that could be the CPU, I can try to get a CPU profile, if you can direct me on how to do that for Cake…

Pete


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  reply	other threads:[~2017-02-10  9:21 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-09 16:36 Pete Heist
2017-02-09 20:52 ` Jonathan Morton
2017-02-10  8:04   ` Pete Heist
2017-02-10  8:49     ` Jonathan Morton
2017-02-10  9:21       ` Pete Heist [this message]
2017-02-10  9:29         ` Jonathan Morton
2017-02-10 10:05           ` Pete Heist
2017-02-10 10:31             ` Jonathan Morton
2017-02-10 11:08               ` Pete Heist
2017-02-10 11:35                 ` Sebastian Moeller
2017-02-10 12:21                   ` Pete Heist
2017-02-12 12:43                     ` Pete Heist
2017-02-12 13:08                       ` Dave Taht
2017-02-12 14:12                         ` Pete Heist
2017-02-12 16:37                           ` Pete Heist
2017-02-12 16:41                           ` Jonathan Morton
2017-02-12 17:15                             ` Pete Heist
2017-02-14 10:02                               ` Pete Heist

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