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  1. Feb 05, 2019
    • Sergei Shtylyov's avatar
      sh_eth: offload RX checksum on R7S72100 · 48132cd0
      Sergei Shtylyov authored
      
      
      The RZ/A1H (R7S721000) SoC manual describes the Ether MAC's RX checksum
      offload the same way as it's implemented in the EtherAVB MACs...
      
      Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      48132cd0
    • Sergei Shtylyov's avatar
      sh_eth: RX checksum offload support · f8e022db
      Sergei Shtylyov authored
      Add support for the 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
      
      Some Ether MACs provide 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. The same checksumming
      scheme is implemented in the EtherAVB MACs and now supported by the 'ravb'
      driver.
      
      In terms of performance, throughput is close to gigabit line rate with the
      RX checksum offload both enabled and disabled.  The '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:
      
      ~/netperf-2.2pl4# perf record -a ./netperf -t TCP_MAERTS -H 192.168.2.4
      TCP MAERTS TEST to 192.168.2.4
      Recv   Send    Send
      Socket Socket  Message  Elapsed
      Size   Size    Size     Time     Throughput
      bytes  bytes   bytes    secs.    10^6bits/sec
      
      131072  16384  16384    10.01     933.93
      [ perf record: Woken up 8 times to write data ]
      [ perf record: Captured and wrote 1.955 MB perf.data (41940 samples) ]
      ~/netperf-2.2pl4# perf report
      Samples: 41K of event 'cycles:ppp', Event count (approx.): 9915302763
      Overhead  Command          Shared Object             Symbol
         9.44%  netperf          [kernel.kallsyms]         [k] __arch_copy_to_user
         7.75%  swapper          [kernel.kallsyms]         [k] _raw_spin_unlock_irq
         6.31%  swapper          [kernel.kallsyms]         [k] default_idle_call
         5.89%  swapper          [kernel.kallsyms]         [k] arch_cpu_idle
         4.37%  swapper          [kernel.kallsyms]         [k] tick_nohz_idle_exit
         4.02%  netperf          [kernel.kallsyms]         [k] _raw_spin_unlock_irq
         2.52%  netperf          [kernel.kallsyms]         [k] preempt_count_sub
         1.81%  netperf          [kernel.kallsyms]         [k] tcp_recvmsg
         1.80%  netperf          [kernel.kallsyms]         [k] _raw_spin_unlock_irqres
         1.78%  netperf          [kernel.kallsyms]         [k] preempt_count_add
         1.36%  netperf          [kernel.kallsyms]         [k] __tcp_transmit_skb
         1.20%  netperf          [kernel.kallsyms]         [k] __local_bh_enable_ip
         1.10%  netperf          [kernel.kallsyms]         [k] sh_eth_start_xmit
      
      Test results with RX checksum offload disabled:
      
      ~/netperf-2.2pl4# perf record -a ./netperf -t TCP_MAERTS -H 192.168.2.4
      TCP MAERTS TEST to 192.168.2.4
      Recv   Send    Send
      Socket Socket  Message  Elapsed
      Size   Size    Size     Time     Throughput
      bytes  bytes   bytes    secs.    10^6bits/sec
      131072  16384  16384    10.01     932.04
      [ perf record: Woken up 14 times to write data ]
      [ perf record: Captured and wrote 3.642 MB perf.data (78817 samples) ]
      ~/netperf-2.2pl4# perf report
      Samples: 78K of event 'cycles:ppp', Event count (approx.): 18091442796
      Overhead  Command          Shared Object       Symbol
         7.00%  swapper          [kernel.kallsyms]   [k] do_csum
         3.94%  swapper          [kernel.kallsyms]   [k] sh_eth_poll
         3.83%  ksoftirqd/0      [kernel.kallsyms]   [k] do_csum
         3.23%  swapper          [kernel.kallsyms]   [k] _raw_spin_unlock_irq
         2.87%  netperf          [kernel.kallsyms]   [k] __arch_copy_to_user
         2.86%  swapper          [kernel.kallsyms]   [k] arch_cpu_idle
         2.13%  swapper          [kernel.kallsyms]   [k] default_idle_call
         2.12%  ksoftirqd/0      [kernel.kallsyms]   [k] sh_eth_poll
         2.02%  swapper          [kernel.kallsyms]   [k] _raw_spin_unlock_irqrestore
         1.84%  swapper          [kernel.kallsyms]   [k] __softirqentry_text_start
         1.64%  swapper          [kernel.kallsyms]   [k] tick_nohz_idle_exit
         1.53%  netperf          [kernel.kallsyms]   [k] _raw_spin_unlock_irq
         1.32%  netperf          [kernel.kallsyms]   [k] preempt_count_sub
         1.27%  swapper          [kernel.kallsyms]   [k] __pi___inval_dcache_area
         1.22%  swapper          [kernel.kallsyms]   [k] check_preemption_disabled
         1.01%  ksoftirqd/0      [kernel.kallsyms]   [k] _raw_spin_unlock_irqrestore
      
      The above results collected on the R-Car V3H Starter Kit board.
      
      Based on the commit 4d86d381
      
       ("ravb: RX checksum offload")...
      
      Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f8e022db
    • Sergei Shtylyov's avatar
      sh_eth: rename sh_eth_cpu_data::hw_checksum · 2c2ab5af
      Sergei Shtylyov authored
      Commit 62e04b7e
      
       ("sh_eth: rename 'sh_eth_cpu_data::hw_crc'") renamed
      the field to 'hw_checksum' for the Ether DMAC "intelligent checksum",
      however some Ether MACs implement a simpler checksumming scheme, so that
      name now seems misleading. Rename that field to 'csmr' as the "intelligent
      checksum" is always controlled by the CSMR register.
      
      Signed-off-by: default avatarSergei Shtylyov <sergei.shtylyov@cogentembedded.com>
      Reviewed-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      2c2ab5af
  2. Feb 04, 2019
  3. Feb 03, 2019