packet: respect devices with LLTX flag in direct xmit
Quite often it can be useful to test with dummy or similar devices as a blackhole sink for skbs. Such devices are only equipped with a single txq, but marked as NETIF_F_LLTX as they do not require locking their internal queues on xmit (or implement locking themselves). Therefore, rather use HARD_TX_{UN,}LOCK API, so that NETIF_F_LLTX will be respected. trafgen mmap/TX_RING example against dummy device with config foo: { fill(0xff, 64) } results in the following performance improvements for such scenarios on an ordinary Core i7/2.80GHz: Before: Performance counter stats for 'trafgen -i foo -o du0 -n100000000' (10 runs): 160,975,944,159 instructions:k # 0.55 insns per cycle ( +- 0.09% ) 293,319,390,278 cycles:k # 0.000 GHz ( +- 0.35% ) 192,501,104 branch-misses:k ( +- 1.63% ) 831 context-switches:k ...
parent
b7d47ca2
Please register or sign in to comment