download

System Configuration—Tuning PerformanceIf you are increasing the buffer spaces to a number larger than 65536,make sure the other ends of connection also support TCP window scalingoptions according to the RFC1323. Otherwise, you will not see anyperformance improvement over your connections.Network Interface PollingDevice polling lets system poll devices, instead of waiting for hardware devices,to generate hardware interrupts. Device polling will greatly enhance the NICperformance on FreeBSD. However, this feature is not enabled in the FreeBSD'sGENERIC kernel and needs manual kernel reconfiguration, to be enabled.To enable device polling support to kernel, the following two lines should be addedto your kernel configuration file:optionsoptionsDEVICE_POLLINGHZ=1000Please note that we have also slowed down the system clock ticks to prevent thesystem from spending a lot of time on poll devices.Once you have recompiled the kernel with the above options in your kernelconfiguration files, the device polling feature will be enabled in your kernel. Thepolling behavior can be controlled by the kern.polling set of variables. To see a listof available variables along with a short description, you may use:# sysctl –d kern.pollingThe ifconfig(8) utility offers a few options to control the polling feature onnetwork interfaces. To enable polling on a specific interface, you may use thefollowing command:# ifconfig bge0 pollingThis will enable polling on the bge0 network interface. This can be verified by usingifconfig again:# ifconfig bge0bge0: flags=8843 metric0 mtu 1500options=48ether 00:0c:6e:7b:74:42inet 192.168.0.5 netmask 0xffffff00 broadcast 192.168.0.255media: Ethernet autoselect (100baseTX )status: active[ 96 ]