Use BBR with qdisc tweaks

[testcaoy7]

1, Fair Queuing
BBR require an qdisc that can do fair queuing such as fq.

2, Pacing

ethtool -K eth0 tso off
tc qdisc add dev eth0 root fq maxrate 1gbit

3, Cake is better
Cake is another qdisc that can do fair queuing.

ethtool -K eth0 tso off
tc qdisc replace dev eth0 root cake rtt 170 bandwidth 1Gbps ethernet besteffort srchost no-split-gso

rtt in ms, can be taken from ping to VPS.

Speed should have some degree of improvement after tweaking qdisc.