Linux/Network Performance Optimisation

1. Increase txqueuelen of the interfaces.

$ ifconfig eth0 txqueuelen 5000

2. increase following kernel params

$ systcl -w net.core.rmem_max = 33554432
$ systcl -w net.core.wmem_max = 33554432
$ systcl -w net.ipv4.tcp_rmem="4096 87380 33554432"
$ systcl -w net.ipv4.tcp_wmem="4096 65536 33554432"
$ sysctl -w net.ipv4.tcp_window_scaling=1
$ sysctl -w net.ipv4.tcp_timestamps=1
$ sysctl -w net.ipv4.tcp_sack=1
$ sysctl -w net.ipv4.udp_rmem_min = 8192
$ sysctl -w net.ipv4.udp_wmem_min = 8192

for the parameter's description click here

3. Disable Segmentation and Checksum

$ ethtool -K eth0 gso off
$ ethtool -K eth0 tso off
$ ethtool -K eth0 ufo off

Reference

1. Linux Web Server Kernel Tuning
2. Optimizing System Performance for SIP servers
3. Linux TCP Tunning
4. Kamailio TCP Tunning

Enjoy ;)