This repository contains the new slow start algorithm that: 1) uses ack-pairs to estimate the bandwidth, and 2) correspondingly sets the ssthresh based on the bandwidth estimate and the round-trip time.

To build the Linux kernel source installed.

Ubuntu:

1. sudo apt-get install linux-source

Raspberry Pi:

1a. Run rpi-update (https://github.com/Hexxeh/rpi-update)

1b. Install and run rpi-source (https://github.com/RPi-Distro/rpi-source)

The kernel needs to be recompiled with a larger ICSK_CA_PRIV_SIZE. Edit:

include/net/inet_connection_sock.h

and for these lines:

  u64                       icsk_ca_priv[104 / sizeof(u64)];
  
  #define ICSK_CA_PRIV_SIZE      (13 * sizeof(u64))

change the number 104 to 2800 and 13 to 350. Then rebuild and reboot the kernel normally.

1. Test modules work via the Hello World kernel module (https://github.com/RPi-Distro/rpi-source#hello-world-example).

2. Then, type 'make'

Check available congestion control algs:

sysctl net.ipv4.tcp_available_congestion_control

Check current congestion control alg:

cat /proc/sys/net/ipv4/tcp_congestion_control

Set current congestion control alg:

sudo sh -c "echo 'cubic_bw' > /proc/sys/net/ipv4/tcp_congestion_control"

Load a module:

sudo insmod tcp_cubic_bw.ko

Load a module (here, setting the debug parameter):

sudo insmod tcp_cubic_bw.ko debug=1

Unload a module:

sudo rmmod tcp_cubic_bw

Disable hystart:

sudo sh -c "echo 0 > /sys/module/tcp_cubic/parameters/hystart"

See also bin/ directory for utilities.