Commits
Manish Chopra committed 8a8633978b8
qede: Add build_skb() support. This patch makes use of build_skb() throughout in driver's receieve data path [HW gro flow and non HW gro flow]. With this, driver can build skb directly from the page segments which are already mapped to the hardware instead of allocating new SKB via netdev_alloc_skb() and memcpy the data which is quite costly. This really improves performance (keeping same or slight gain in rx throughput) in terms of CPU utilization which is significantly reduced [almost half] in non HW gro flow where for every incoming MTU sized packet driver had to allocate skb, memcpy headers etc. Additionally in that flow, it also gets rid of bunch of additional overheads [eth_get_headlen() etc.] to split headers and data in the skb. Tested with: system: 2 sockets, 4 cores per socket, hyperthreading, 2x4x2=16 cores iperf [server]: iperf -s iperf [client]: iperf -c <server_ip> -t 500 -i 10 -P 32 HW GRO off – w/o build_skb(), throughput: 36.8 Gbits/sec Average: CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle Average: all 0.59 0.00 32.93 0.00 0.00 43.07 0.00 0.00 23.42 HW GRO off - with build_skb(), throughput: 36.9 Gbits/sec Average: CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle Average: all 0.70 0.00 31.70 0.00 0.00 25.68 0.00 0.00 41.92 HW GRO on - w/o build_skb(), throughput: 36.9 Gbits/sec Average: CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle Average: all 0.86 0.00 24.14 0.00 0.00 6.59 0.00 0.00 68.41 HW GRO on - with build_skb(), throughput: 37.5 Gbits/sec Average: CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle Average: all 0.87 0.00 23.75 0.00 0.00 6.19 0.00 0.00 69.19 Signed-off-by: Ariel Elior <ariel.elior@cavium.com> Signed-off-by: Manish Chopra <manish.chopra@cavium.com> Signed-off-by: David S. Miller <davem@davemloft.net>