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Date:      Tue, 31 Jan 2023 17:03:08 -0500
From:      Paul Mather <paul@gromit.dlib.vt.edu>
To:        David <2yt@gmx.com>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: Slow WAN traffic to FreeBSD hosts but not to Linux hosts---how to debug/fix?
Message-ID:  <A3E14937-0CC7-4C4F-ABAE-7DA37CDD7BE7@gromit.dlib.vt.edu>
In-Reply-To: <ee8df505-cd76-41fb-25a6-cb5c67dc5d8c@gmx.com>
References:  <95EDCFCA-7E3F-458F-85A6-856D606B9D98@gromit.dlib.vt.edu> <tr9g44$d3l$1@ciao.gmane.io> <CANwXMPNBkWQHzT4f%2Bjy0RV1gK7R6nJOWYsG5NZTf9RadRDNfXg@mail.gmail.com> <ee8df505-cd76-41fb-25a6-cb5c67dc5d8c@gmx.com>

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On Jan 31, 2023, at 10:39 AM, David <2yt@gmx.com> wrote:

> On 1/30/23 16:30, Matt Garber wrote:
>>     > Any help/insight is gratefully appreciated.
>>     >
>>     > Cheers,
>>     >
>>     > Paul.
>>     >
>>    sysctl net.inet.tcp.cc.algorithm=3Dhtcp
>>    I would set "htcp" on the server and home computer to improve
>>    through in
>>    your type of situation.
>> There may be other FreeBSD sysctls that have bad defaults in this =
scenario and could be better tuned, but I doubt changing the CC =
algorithm at this point is the problem =E2=80=94 at least not so much a =
problem that=E2=80=99s causing throughput to be reduced so drastically. =
Happy to be wrong if that does help things quickly and easily, though.
>> (Since OP mentioned that FreeBSD CC was set to CUBIC, that would =
match what the Linux boxes are using by default, too, unless they=E2=80=99=
ve been changed to something newer like BBR=E2=80=A6 so seems like CUBIC =
*should* be performing fine on this WAN link, and the difference is =
something else.)
>> =E2=80=94Matt
>=20
> I love FreeBSD and very much appreciate the efforts of those people =
much smarter. But... I don't think the defaults get enough testing in =
real world conditions.
>=20
> I came across Paul's issue several years ago and spent a few a hours =
testing and found the defaults performed very well on a LAN but could =
perform terribly on a many hop WAN. HTCP performs marginally worse on a =
LAN or close WAN connection, but much much better on a many hop WAN =
connection.
>=20
[[...]]

> In my opinion HTCP is a better default for the current state of the =
internet.


It looks like they already changed the default from NewReno to CUBIC in =
FreeBSD-CURRENT.

I agree with your observation about the defaults vs. real world =
conditions.  As you observed, I also get great performance in a =
high-speed LAN, but not so much in a many-hop WAN to an asymmetric ISP =
connection.

I actually started down this rabbit hole when I noticed I couldn't =
manage more than about 3--4 MB in a single stream and thought my ISP was =
throttling me.  But then I noticed I would actually get fast/maximum =
speeds, e.g., when doing "brew upgrade -v" and Homebrew would be =
downloading packages, and so then wondered whether they were throttling =
non-HTTP traffic.  That led me to discover that even HTTP downloads were =
slow to the FreeBSD servers I use remotely at $JOB and, furthermore, =
that all traffic to Linux systems I use at $JOB didn't seem to be =
throttled or incapable of getting maximum single stream bandwidth =
matching my ISP's quoted speeds. :-\

I accept that this may just be a peculiarity of my local and remote =
setup, and so appreciate the help and suggestions people have offered in =
trying to debug the issue.

Cheers,

Paul.=



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