[Cake] Long-RTT broken again

Toke Høiland-Jørgensen toke at toke.dk
Sat Nov 7 08:42:45 EST 2015

Jonathan Morton <chromatix99 at gmail.com> writes:

> Okay, that seems to be working somewhat better now.  I’m still not
> getting 100Mbps throughput in either direction, but now it seems to be
> because the receive windows won’t open far enough - there’s enough
> buffering to prevent any packet loss.

Yeah, Linux is window limited at these BDPs with the default settings.
Try these sysctls on both sides:

net.ipv4.tcp_rmem = 4096 87380 104857600
net.ipv4.tcp_wmem = 4096 16384 104857600


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