Hi, [Only applies to MP safe tests]
The effect of my recent changes to interface<->ethernet is at: http://leaf.dragonflybsd.org/~sephe/fwd/comp00_0123.png http://leaf.dragonflybsd.org/~sephe/fwd/comp01_0123.png I think the above two cases is the most common use cases, and the current throughput almost doubles the old one. The ETHER_CHAIN_INPUT effect is not obvious in above two cases, but its effect is quite obvious, when if_start does not contend: http://leaf.dragonflybsd.org/~sephe/fwd/comp00_1.png http://leaf.dragonflybsd.org/~sephe/fwd/comp01_2.png The results of various tests mentioned in: http://leaf.dragonflybsd.org/~sephe/fwd/readme.txt are shown at: http://leaf.dragonflybsd.org/~sephe/fwd/data00.png http://leaf.dragonflybsd.org/~sephe/fwd/data01.png I also compared fastforwarding and non-fastforwarding on HEAD: http://leaf.dragonflybsd.org/~sephe/fwd/data_ff_nff.png NOTE: There IS performance regression introduced in fastforwarding when reducing if_start serializer contention: http://leaf.dragonflybsd.org/~sephe/fwd/compff.png But even with the best fastforwarding result (max at 520Kpps), it is still _quite_ slower than non-fastforwarding. The comparison of two major changes under various tests are at: http://leaf.dragonflybsd.org/~sephe/fwd/comp0[01]_xxx.png There are two regression under specific tests: 1) em0 on cpu0, em1 on cpu1, stream target cpu1: http://leaf.dragonflybsd.org/~sephe/fwd/comp01_1.png 2) em0 on cpu0, em1 on cpu1, stream target cpu0: http://leaf.dragonflybsd.org/~sephe/fwd/comp00_0.png I have studied 1) with ktr: in udp_thread, each packet enqueueing triggers if_start, and if_start interlock checking happens for each packets. I have experimented one solution, which utilizes our lwkt scheduling feature: schedule if_start on the same CPU but in different thread. This solution is not as good as the current one in most cases, especially when packets are spread evenly on each CPUs. No matter what, I think I currently have a relative good ground to keep moving on :) Best Regards, sephe -- Live Free or Die
![http://leaf.dragonflybsd.org/~sephe/fwd/comp0[01]_xxx.png](http://leaf.dragonflybsd.org/~sephe/fwd/comp0[01]_xxx.png){kind=link}
