On 10/04/2017 10:54 AM, Simon Horman wrote:
Add support for RX checksum offload. This is enabled by default and may be disabled and re-enabled using ethtool:# ethtool -K eth0 rx off # ethtool -K eth0 rx on The RAVB provides a simple checksumming scheme which appears to be completely compatible with CHECKSUM_COMPLETE: sum of all packet data after the L2 header is appended to packet data; this may be trivially read by the driver and used to update the skb accordingly. In terms of performance throughput is close to gigabit line-rate both with and without RX checksum offload enabled. Perf output, however, appears to indicate that significantly less time is spent in do_csum(). This is as expected. Test results with RX checksum offload enabled: # /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162 MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 937.54 Summary of output of perf report: 18.28% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore 10.34% ksoftirqd/0 [kernel.kallsyms] [k] __pi_memcpy 9.83% ksoftirqd/0 [kernel.kallsyms] [k] ravb_poll 7.89% ksoftirqd/0 [kernel.kallsyms] [k] skb_put 4.01% ksoftirqd/0 [kernel.kallsyms] [k] dev_gro_receive 3.37% netperf [kernel.kallsyms] [k] __arch_copy_to_user 3.17% swapper [kernel.kallsyms] [k] arch_cpu_idle 2.55% swapper [kernel.kallsyms] [k] tick_nohz_idle_enter 2.04% ksoftirqd/0 [kernel.kallsyms] [k] __pi___inval_dcache_area 2.03% swapper [kernel.kallsyms] [k] _raw_spin_unlock_irq 1.96% ksoftirqd/0 [kernel.kallsyms] [k] __netdev_alloc_skb 1.59% ksoftirqd/0 [kernel.kallsyms] [k] __slab_alloc.isra.83 Test results without RX checksum offload enabled: # /usr/bin/perf_3.16 record -o /run/perf.data -a netperf -t TCP_MAERTS -H 10.4.3.162 MIGRATED TCP MAERTS TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 10.4.3.162 () port 0 AF_INET : demo enable_enobufs failed: getprotobyname Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 940.20 Summary of output of perf report: 17.10% ksoftirqd/0 [kernel.kallsyms] [k] _raw_spin_unlock_irqrestore 10.99% ksoftirqd/0 [kernel.kallsyms] [k] __pi_memcpy 8.87% ksoftirqd/0 [kernel.kallsyms] [k] ravb_poll 8.16% ksoftirqd/0 [kernel.kallsyms] [k] skb_put 7.42% ksoftirqd/0 [kernel.kallsyms] [k] do_csum 3.91% ksoftirqd/0 [kernel.kallsyms] [k] dev_gro_receive 2.31% swapper [kernel.kallsyms] [k] arch_cpu_idle 2.16% ksoftirqd/0 [kernel.kallsyms] [k] __pi___inval_dcache_area 2.14% ksoftirqd/0 [kernel.kallsyms] [k] __netdev_alloc_skb 1.93% netperf [kernel.kallsyms] [k] __arch_copy_to_user 1.79% swapper [kernel.kallsyms] [k] tick_nohz_idle_enter 1.63% ksoftirqd/0 [kernel.kallsyms] [k] __slab_alloc.isra.83 Above results collected on an R-Car Gen 3 Salvator-X/r8a7796 ES1.0. Also tested on a R-Car Gen 3 Salvator-X/r8a7795 ES1.0. By inspection this also appears to be compatible with the ravb found on R-Car Gen 2 SoCs, however, this patch is currently untested on such hardware. Signed-off-by: Simon Horman <horms+rene...@verge.net.au> --- v2 Address review of v1 by Sergei Shtylyov * set features rather than oring them with (zero) existing values: * Set/unset using a single call to ravb_modify()
Already belated but still: Reviewed-by: Sergei Shtylyov <sergei.shtyl...@cogentembedded.com> MBR, Sergei
