[Bloat] WSL2 + fq_codel

[Dave Taht]

On Mon, Feb 27, 2023 at 4:11 AM Maximilian Bachl
<maximilian.bachl at gmail.com> wrote:
>
> Yes, the default interface of WSL2 seems to use fq_codel:
>
> $ tc qdisc show dev eth0
> qdisc mq 0: root
> qdisc fq_codel 0: parent :8 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :7 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :6 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :5 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :4 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :3 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :2 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn
> qdisc fq_codel 0: parent :1 limit 10240p flows 1024 quantum 1514 target 5.0ms interval 100.0ms memory_limit 32Mb ecn

yay! Is there any sign that it is actually working as designed here
(load it up with 16+ flows, see if you had drops or reschedules via tc
-s qdisc show)

> On Sat, Feb 25, 2023 at 11:07 PM Dave Taht via Bloat <bloat at lists.bufferbloat.net> wrote:
>>
>> On Sat, Feb 25, 2023 at 12:54 PM Stephen Hemminger
>> <stephen at networkplumber.org> wrote:
>> >
>> > On Sat, 25 Feb 2023 15:37:02 -0500
>> > Michael Richardson via Bloat <bloat at lists.bufferbloat.net> wrote:
>> >
>> > > Dave Taht via Bloat <bloat at lists.bufferbloat.net> wrote:
>> > >     > I so want to believe... I so want to believe... can anyone confirm?
>> > >
>> > >     > https://raw.githubusercontent.com/microsoft/WSL2-Linux-Kernel/linux-msft-wsl-5.15.y/Microsoft/config-wsl
>> > >
>> > > But, AFAIK, WSL isn't a kernel.  It's an implementation of the Linux ABI on
>> > > top of Windows service(s).  If you told me that they build some of it from
>> > > actual Linux kernel sources, I'd believe you.  (Rather like User-Mode-Linux)
>> > >
>> > > If you told me that they have a kernel that they build for when they actually
>> > > spin up an actual VM (such as to run containers) that would also be unsurprising.
>> > >
>> > >     > ...
>> > >
>> > >     > CONFIG_NET_SCH_DEFAULT=y
>> > >     > CONFIG_DEFAULT_FQ_CODEL=y
>> > >     > # CONFIG_DEFAULT_PFIFO_FAST is not set
>> > >     > CONFIG_DEFAULT_NET_SCH="fq_codel"
>> > >
>> > > It would be nice if the billion windows desktops started doing
>> > > something better, but I don't think it will help observed latency.
>> > > The real question is what the default schedule for the default Azure Linux VM
>> > > is.
>> > >
>> >
>> > I think WSL2 is actually a full Linux VM running in Hyper-V.
>>
>> Yes, it is. But it is kind of unknown how the underlying network
>> interface is behaving in this case, as well as what the actual default
>> qdisc is, and this not just a random gist. It was VERY exciting to see
>> that gist go by...
>>
>> are there no windows users on this list? :/ We long ago should have
>> pursued at least flent, and a TCP_INFO equivalent sampling method for
>> windows. The closest thing we have for windows is the rust-based:
>> https://github.com/Zoxc/crusader
>>
>> --
>> A pithy note on VOQs vs SQM: https://blog.cerowrt.org/post/juniper/
>> Dave Täht CEO, TekLibre, LLC
>> _______________________________________________
>> Bloat mailing list
>> Bloat at lists.bufferbloat.net
>> https://lists.bufferbloat.net/listinfo/bloat



-- 
A pithy note on VOQs vs SQM: https://blog.cerowrt.org/post/juniper/
Dave Täht CEO, TekLibre, LLC