How to improve Wireguard speed?

[Houman]

Thanks for your reply.

I have run htop to observe the CPU consumption during this test, and
the CPU(s) go up only to 10-20%. So the CPU doesn't seem to be the
bottleneck.

I didn't change the MTU settings, but I have a suspicion about MTU. I
found this article here that makes some interesting suggestions to set
MTU to 1280: https://keremerkan.net/posts/wireguard-mtu-fixes/

And beyond that iptables -A FORWARD -p tcp --tcp-flags SYN,RST SYN -j
TCPMSS --clamp-mss-to-pmtu





On Wed, 1 Jun 2022 at 09:51, Janne Johansson <icepic.dz at gmail.com> wrote:
>
> Den ons 1 juni 2022 kl 09:49 skrev Houman <houmie at gmail.com>:
> > Hello,
> > I'm compiling the latest stable Wireguard on Debian 11.
> > git clone https://git.zx2c4.com/wireguard-tools
> > make -C wireguard-tools/src -j$(nproc)
> > sudo make -C wireguard-tools/src install
> >
> > However the speed is not that impressive.  I have a VPS with 4 vCores
> > and 8 GB RAM on 1 Gbps network.  The VPS is located in London and so
> > am I.
> >
> > With wireguard enabled I get 117 Mbps
> > Without wireguard I get 506 Mbps
> >
> > That's a drop of 75%. What are the factors to improve the download rate?
>
> That seems like very poor values, I would make two tests, one local to
> the VPS and one test local to the other end (which you left out of the
> description) and see which one is the limiting box. People (including
> me) have easily gotten speeds at 1-2 gigabit on 10GE networked
> computers and VPSes and several gigabits on loopbacks, so the fault is
> not simply using wireguard.
>
> If you check the results of the nightly builds for x86_64 at
> https://www.wireguard.com/build-status/ you find several iperf3 runs
> that end up over 2-3 Gbit/s when a box is talking "to itself" so it's
> not the crypto or the tunnel that prevents you from filling up the
> gigabit link. Perhaps the VPS isn't giving you a lot of cpu? Perhaps
> the test reacts poorly to the lowered MTU for using (any) tunnel in
> between?
>
> --
> May the most significant bit of your life be positive.