[Cake] [PATCH 0/3] Add Common Applications Kept Enhanced (sch_cake) qdisc
Sebastian Moeller
moeller0 at gmx.de
Thu Nov 23 02:54:41 EST 2017
Hi Dave,
> On Nov 22, 2017, at 19:03, Dave Taht <dave.taht at gmail.com> wrote:
>
> at what commit it worked properly?
That is a good question, I will need to research that (and I also should consider the possibilirty that maybe this issue is more related to my ubuntu 16.4 LTS's Linux kernel: work-horse 4.10.0-38-generic #42~16.04.1-Ubuntu SMP Tue Oct 10 16:32:20 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux). Now it shows that I am quite a git novice, but I guess "git bisect" should be my friend here, assuming I can divine a initial good commit.. For that could you help me out with which command I need to use to "checkout/rewind to" a specific git commit, so I can easily confirm I start with a known good state?
You might be able to tell this is all new territory for me, so it might take longer than I would wish...
Best Regards
>
> On Wed, Nov 22, 2017 at 3:02 AM, Sebastian Moeller <moeller0 at gmx.de> wrote:
>> Hi All,
>>
>> Tl;dr: Automatic accounting of the kernel added dev->hard_header_len seems currently broken at least in the cobalt branch...
>>
>>
>> as far as I can tell overhead accounting is still busted:
>>
>>
>> user at work-horse:~/CODE/sch_cake$ sudo ../tc-adv/tc/tc qdisc delete dev eth0 root; sudo ../tc-adv/tc/tc qdisc replace dev eth0 root cake raw overhead 5; ../tc-adv/tc/tc -s qdisc show dev eth0
>> sudo: unable to resolve host work-horse
>> sudo: unable to resolve host work-horse
>> qdisc cake 8014: root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms noatm overhead 19 via-ethernet total_overhead 19 hard_header_len 14
>> Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>> backlog 0b 0p requeues 0
>> memory used: 0b of 15140Kb
>> capacity estimate: 0bit
>> Bulk Best Effort Voice
>> thresh 0bit 0bit 0bit
>> target 5.0ms 5.0ms 5.0ms
>> interval 100.0ms 100.0ms 10.0ms
>> pk_delay 0us 0us 0us
>> av_delay 0us 0us 0us
>> sp_delay 0us 0us 0us
>> pkts 0 0 0
>> bytes 0 0 0
>> way_inds 0 0 0
>> way_miss 0 0 0
>> way_cols 0 0 0
>> drops 0 0 0
>> marks 0 0 0
>> ack_drop 0 0 0
>> sp_flows 0 0 0
>> bk_flows 0 0 0
>> un_flows 0 0 0
>> max_len 0 0 0
>>
>> user at work-horse:~/CODE/sch_cake$ sudo ../tc-adv/tc/tc qdisc delete dev eth0 root; sudo ../tc-adv/tc/tc qdisc replace dev eth0 root cake overhead 5; ../tc-adv/tc/tc -s qdisc show dev eth0
>> sudo: unable to resolve host work-horse
>> sudo: unable to resolve host work-horse
>> qdisc cake 8015: root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms raw total_overhead 14 hard_header_len 14
>> Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>> backlog 0b 0p requeues 0
>> memory used: 0b of 15140Kb
>> capacity estimate: 0bit
>> Bulk Best Effort Voice
>> thresh 0bit 0bit 0bit
>> target 5.0ms 5.0ms 5.0ms
>> interval 100.0ms 100.0ms 10.0ms
>> pk_delay 0us 0us 0us
>> av_delay 0us 0us 0us
>> sp_delay 0us 0us 0us
>> pkts 0 0 0
>> bytes 0 0 0
>> way_inds 0 0 0
>> way_miss 0 0 0
>> way_cols 0 0 0
>> drops 0 0 0
>> marks 0 0 0
>> ack_drop 0 0 0
>> sp_flows 0 0 0
>> bk_flows 0 0 0
>> un_flows 0 0 0
>> max_len 0 0 0
>>
>> user at work-horse:~/CODE/sch_cake$
>>
>>
>> The first seems okay, but the second should not have reported "raw" but rather total_overhead 5 hard_header_len 14 if I understand the intention of the overhead keyword correctly. This also affects the keywords like conservative:
>>
>> user at work-horse:~/CODE/sch_cake$ sudo ../tc-adv/tc/tc qdisc delete dev eth0 root; sudo ../tc-adv/tc/tc qdisc replace dev eth0 root cake conservative; ../tc-adv/tc/tc -s qdisc show dev eth0
>> sudo: unable to resolve host work-horse
>> sudo: unable to resolve host work-horse
>> qdisc cake 8019: root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms atm overhead 14 via-ethernet total_overhead 14 hard_header_len 14
>> Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>> backlog 0b 0p requeues 0
>> memory used: 0b of 15140Kb
>> capacity estimate: 0bit
>> Bulk Best Effort Voice
>> thresh 0bit 0bit 0bit
>> target 5.0ms 5.0ms 5.0ms
>> interval 100.0ms 100.0ms 10.0ms
>> pk_delay 0us 0us 0us
>> av_delay 0us 0us 0us
>> sp_delay 0us 0us 0us
>> pkts 0 0 0
>> bytes 0 0 0
>> way_inds 0 0 0
>> way_miss 0 0 0
>> way_cols 0 0 0
>> drops 0 0 0
>> marks 0 0 0
>> ack_drop 0 0 0
>> sp_flows 0 0 0
>> bk_flows 0 0 0
>> un_flows 0 0 0
>> max_len 0 0 0
>>
>> user at work-horse:~/CODE/sch_cake$ sudo ../tc-adv/tc/tc qdisc delete dev eth0 root; sudo ../tc-adv/tc/tc qdisc replace dev eth0 root cake raw conservative; ../tc-adv/tc/tc -s qdisc show dev eth0
>> sudo: unable to resolve host work-horse
>> sudo: unable to resolve host work-horse
>> qdisc cake 801a: root refcnt 6 unlimited diffserv3 triple-isolate rtt 100.0ms atm overhead 62 via-ethernet total_overhead 62 hard_header_len 14
>> Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
>> backlog 0b 0p requeues 0
>> memory used: 0b of 15140Kb
>> capacity estimate: 0bit
>> Bulk Best Effort Voice
>> thresh 0bit 0bit 0bit
>> target 5.0ms 5.0ms 5.0ms
>> interval 100.0ms 100.0ms 10.0ms
>> pk_delay 0us 0us 0us
>> av_delay 0us 0us 0us
>> sp_delay 0us 0us 0us
>> pkts 0 0 0
>> bytes 0 0 0
>> way_inds 0 0 0
>> way_miss 0 0 0
>> way_cols 0 0 0
>> drops 0 0 0
>> marks 0 0 0
>> ack_drop 0 0 0
>> sp_flows 0 0 0
>> bk_flows 0 0 0
>> un_flows 0 0 0
>> max_len 0 0 0
>>
>> user at work-horse:~/CODE/sch_cake$
>>
>>
>> So in other words currently the automatic accounting for the kernel added hard_header_len seems broken as the raw keyword disables that functionality. I will try to look deeper into that, but I guess with my limited C skills this might do more harm than good...
>>
>> Best Regards
>> Sebastian
>>
>>
>>> On Nov 22, 2017, at 01:09, Dave Taht <dave.taht at gmail.com> wrote:
>>>
>>> sch_cake is intended to squeeze the most bandwidth and lowest latency out
>>> of even the slowest ISP links and routers, while presenting an API simple
>>> enough that even an ISP can configure it.
>>>
>>> Example of use on an ISP uplink:
>>>
>>> tc qdisc add dev eth0 cake bandwidth 20Mbit nat docsis ack-filter
>>>
>>> Cake can also be used in unlimited mode to drive packets at the speed
>>> of the underlying link.
>>>
>>> Cake is filled with:
>>>
>>> * A hybrid Codel/Blue AQM algorithm, “Cobalt”, tied to an FQ_Codel
>>> derived Flow Queuing system, which autoconfigures based on the bandwidth.
>>> * A unique "triple-isolate" mode (the default) which balances per-flow
>>> and per-host flow FQ even through NAT.
>>> * An integral deficit based shaper with extensive dsl and docsis support
>>> that can also be used in unlimited mode.
>>> * 8 way set associative queuing to reduce flow collisions to a minimum.
>>> * A reasonable interpretation of various diffserv latency/loss tradeoffs.
>>> * Support for washing diffserv for entering and exiting traffic.
>>> * Perfect support for interacting with Docsis 3.0 shapers.
>>> * Extensive support for DSL framing types.
>>> * (New) Support for ack filtering.
>>> - 20 % better throughput at a 16x1 down/up ratio on the rrul test.
>>> * Extensive statistics for measuring loss, ecn markings, latency variation.
>>>
>>> There are some features still considered experimental, notably the
>>> ingress_autorate bandwidth estimator and cobalt itself.
>>>
>>> Various versions shipping have been available as an out of tree build for
>>> kernel versions going back to 3.10, as the embedded router world has been
>>> running a few years behind mainline Linux. A stable version has been
>>> generally available on lede-17.01 and later.
>>>
>>> sch_cake replaces a combination of iptables, tc filter, htb and fq_codel in
>>> the sqm-scripts, with sane defaults and vastly easier configuration.
>>>
>>> Cake's principal author is Jonathan Morton, with contributions from
>>> Kevin Darbyshire-Bryant, Toke Høiland-Jørgensen, Sebastian Moeller,
>>> Ryan Mounce, Dean Scarff, Guido Sarducci, Nils Andreas Svee, Dave Täht, and
>>> Loganaden Velvindron.
>>>
>>> Dave Taht (3):
>>> pkt_sched.h: add support for sch_cake API
>>> Add Common Applications Kept Enhanced (sch_cake) qdisc
>>> Add support for building the new cake qdisc
>>>
>>> include/net/cobalt.h | 152 +++
>>> include/uapi/linux/pkt_sched.h | 58 +
>>> net/sched/Kconfig | 11 +
>>> net/sched/Makefile | 1 +
>>> net/sched/sch_cake.c | 2551 ++++++++++++++++++++++++++++++++++++++++
>>> 5 files changed, 2773 insertions(+)
>>> create mode 100644 include/net/cobalt.h
>>> create mode 100644 net/sched/sch_cake.c
>>>
>>> --
>>> 2.7.4
>>>
>>> _______________________________________________
>>> Cake mailing list
>>> Cake at lists.bufferbloat.net
>>> https://lists.bufferbloat.net/listinfo/cake
>>
>
>
>
> --
>
> Dave Täht
> CEO, TekLibre, LLC
> http://www.teklibre.com
> Tel: 1-669-226-2619
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