[Cake] Cake latency update

[Pete Heist]

> On Feb 12, 2017, at 6:15 PM, Pete Heist <peteheist at gmail.com> wrote:
> 
>> On Feb 12, 2017, at 5:41 PM, Jonathan Morton <chromatix99 at gmail.com> wrote:
>> 
>>> On 12 Feb, 2017, at 16:12, Pete Heist <peteheist at gmail.com> wrote:
>>> 
>>> 2) Using a 1.25 GHz Mac Mini PPC G4 I have laying around. I successfully ran fq_codel for ADSL on that box in the past, but at 5 / 0.5 Mbps. Accurate Flent results running Cake at 80 Mbps? Timer issues?
>> 
>> That should be absolutely fine at 80Mbps.  PowerPC Macs seem to have good hi-res timers in my experience, and the Sun GEM is a relatively good NIC.  The main limitation is that it’s PCI rather than PCIe, so it can’t reach the full GigE line rate, but it does go well above 100Mbps.
>> 
>> Don’t worry about BQL, since you’re not relying on NIC backpressure to control queuing.
> 
> Ok, good news, then that’s the way I’ll go! Thanks for that, more results later...


Replacing the MBP (sky2 Ethernet driver) with a PPC G4 with the Sun GEM appears to have fixed the class of five-second-throughput-shifts that I reported earlier. See the much smoother Cake results below. :) I’ll be re-running all of my other tests again.

It does raise a new question though. In the 10 Mbit and 20 Mbit Cake tests, one of the TCP download flows gets a bit starved relative to the average. I was seeing this earlier also before I moved to the PPC. I don’t see this at 30Mbit and above. There is also a latency variation in 75Mbit fq_codel, so I know that sometimes you can just say “it’s Wi-Fi”. I don’t have the time to check this on Ethernet now, but maybe later.

Cake:

http://www.drhleny.cz/bufferbloat/cake_hd-eth_10mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_10mbit/index.html> (partial starvation for one tcp download flow)

http://www.drhleny.cz/bufferbloat/cake_hd-eth_20mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_20mbit/index.html> (partial starvation for one tcp download flow)

http://www.drhleny.cz/bufferbloat/cake_hd-eth_30mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_30mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_40mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_40mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_50mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_50mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_60mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_60mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_70mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_70mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_75mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_75mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_80mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_80mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_85mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_85mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_90mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_90mbit/index.html>

http://www.drhleny.cz/bufferbloat/cake_hd-eth_100mbit/index.html <http://www.drhleny.cz/bufferbloat/cake_hd-eth_100mbit/index.html>

fq_codel:

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_10mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_10mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_20mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_20mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_30mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_30mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_40mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_40mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_50mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_50mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_60mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_60mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_70mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_70mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_75mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_75mbit/index.html> (latency variation and something wrong in one udp flow)

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_80mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_80mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_85mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_85mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_90mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_90mbit/index.html>

http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_100mbit/index.html <http://www.drhleny.cz/bufferbloat/fq_codel_hd-eth_100mbit/index.html>

Pete

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