[Intel-wired-lan] What are management packets (rx_smbus, MGTPRC)?

[Intel-wired-lan] What are management packets (rx_smbus, MGTPRC)?

[Paul Menzel]

Dear Linux folks,


We are trying to debug a network issue, and, while looking at the 
network device statistics, noticed a high value of `rx_smbus`.

     $ sudo ethtool -S net00
     [?]
     tx_smbus: 0
     rx_smbus: 557816
     dropped_smbus: 9
     [?]

This seems unrelated to our problem, but we noticed, that around 20 % of 
our desktops have a positive value. From the source:

     drivers/net/ethernet/intel/e1000/e1000_main.c: 
adapter->stats.mgprc += er32(MGTPRC);
     drivers/net/ethernet/intel/e1000e/ethtool.c: 
E1000_STAT("rx_smbus", stats.mgprc

     drivers/net/ethernet/intel/e1000e/regs.h:#define E1000_MGTPRC 
0x040B4 /* Management Packets Rx Count - R/clr *

Out of curiosity, what are these management packets?


Kind regards,

Paul


$ sudo ethtool -S net00
NIC statistics:
      rx_packets: 993001516
      tx_packets: 1331956350
      rx_bytes: 938128015910
      tx_bytes: 1842492467154
      rx_broadcast: 84929255
      tx_broadcast: 237026
      rx_multicast: 3869371
      tx_multicast: 47602
      rx_errors: 250
      tx_errors: 0
      tx_dropped: 0
      multicast: 3869371
      collisions: 0
      rx_length_errors: 0
      rx_over_errors: 0
      rx_crc_errors: 187
      rx_frame_errors: 0
      rx_no_buffer_count: 0
      rx_missed_errors: 0
      tx_aborted_errors: 0
      tx_carrier_errors: 0
      tx_fifo_errors: 0
      tx_heartbeat_errors: 0
      tx_window_errors: 0
      tx_abort_late_coll: 0
      tx_deferred_ok: 0
      tx_single_coll_ok: 0
      tx_multi_coll_ok: 0
      tx_timeout_count: 0
      tx_restart_queue: 0
      rx_long_length_errors: 0
      rx_short_length_errors: 0
      rx_align_errors: 0
      tx_tcp_seg_good: 31498083
      tx_tcp_seg_failed: 0
      rx_flow_control_xon: 0
      rx_flow_control_xoff: 0
      tx_flow_control_xon: 0
      tx_flow_control_xoff: 0
      rx_csum_offload_good: 927463008
      rx_csum_offload_errors: 34
      rx_header_split: 0
      alloc_rx_buff_failed: 0
      tx_smbus: 0
      rx_smbus: 557816
      dropped_smbus: 9
      rx_dma_failed: 0
      tx_dma_failed: 0
      rx_hwtstamp_cleared: 0
      uncorr_ecc_errors: 0
      corr_ecc_errors: 0
      tx_hwtstamp_timeouts: 0
      tx_hwtstamp_skipped: 0

[Intel-wired-lan] What are management packets (rx_smbus, MGTPRC)?

[Jesse Brandeburg]

Paul Menzel wrote:
>      $ sudo ethtool -S net00
>      [?]
>      tx_smbus: 0
>      rx_smbus: 557816
>      dropped_smbus: 9
>      [?]
> 
> Out of curiosity, what are these management packets?

the rx_smbus packets matched a filter in the hardware and the packets
were redirected to the SMBUS (usually a path to the BMC for IPMI
packets) 

These packets are usually traffic on UDP port 623 (for IPMI) but
whatever host program is connected to the SMBUS can specify it's own
filters as far as I recall.

Hope this helps,
Jesse