15. Optimizing Your OS for Network Performance¶

The network stacks of popular operating systems are not always tuned for maximum performance out of the box. RTI has found that the following configuration changes frequently improve performance for a broad set of demanding applications. Consider testing your network performance with and without these changes to learn if they can benefit your system.

15.1. Optimizing Linux Systems¶

Edit the file /etc/sysctl.conf and add the following:

net.core.wmem_max = 16777216
net.core.wmem_default = 131072
net.core.rmem_max = 16777216
net.core.rmem_default = 131072
net.ipv4.tcp_rmem = 4096 131072 16777216
net.ipv4.tcp_wmem = 4096 131072 16777216
net.ipv4.tcp_mem = 4096 131072 16777216

net.core.netdev_max_backlog = 30000
net.ipv4.ipfrag_high_threshold = 8388608

run /sbin/sysctl -p

15.2. Optimizing Windows Systems¶

From the Start button, select Run…, then enter regedit.
Change this entry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Services\Tcpip\Parameters
- Add the DWORD key: MaximumReassemblyHeaders
- Set the value to 0xffff (this is the max value)
- See http://support.microsoft.com/kb/811003 for more information.
Change this entry: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\ Services\AFD\Parameters
- Add the DWORD key: FastSendDatagramThreshold
- Set the value to 65536 (0x10000) See http://support.microsoft.com/kb/235257 for more information.
Reboot your machine for the changes to take effect.