[Bloat] WSL2 + fq_codel

[Maximilian Bachl]

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

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
>
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