commit aad8b3fefb192f89783f0b1e383f701aafd4f00b Author: Sepherosa Ziehau <se...@dragonflybsd.org> Date: Sun Dec 2 20:30:40 2012 +0800
bge: Improve tiny packets transmission performance on low frequency CPU Update TX HOST_PROD register a little bit often; mainly to improve timeliness of packets transmission: The TX HOST_PROD register is updated after certain amount of TX descriptors are added to the hardware TX ring. The default value of the amount of TX descriptors are 16. This value could be further tuned by per-device sysctl node hw.bgeX.tx_wreg. The default value improves tiny packets transmission performance w/ 5721 on AMD970@800Mhz (770Kpps -> 800Kpps) and it does not increase CPU usage on AMD970@3500Mhz (CPU usage stays @20%, 5721 could only do 810Kpps). NOTE: Tuning hw.bgeX.tx_coal_bds to 32 could make packets transmission performance w/ 5721 on AMD970@800Mhz to be 810Kpps, however, this shows no performance improvement on commonly used CPU frequency like 2200Mhz and 3500Mhz. And this tuning could burden systems not using polling(4). Summary of changes: sys/dev/netif/bge/if_bge.c | 58 ++++++++++++++++++++++++++-------------- sys/dev/netif/bge/if_bgevar.h | 1 + 2 files changed, 39 insertions(+), 20 deletions(-) http://gitweb.dragonflybsd.org/dragonfly.git/commitdiff/aad8b3fefb192f89783f0b1e383f701aafd4f00b -- DragonFly BSD source repository