Uploaded image for project: 'Erlang/OTP'
  1. Erlang/OTP
  2. ERL-959

Distribution inet send_cnt & recv_cnt reports incorrect values

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: Major
    • Resolution: Not a Bug
    • Affects Version/s: 22.0.1
    • Fix Version/s: None
    • Component/s: inets
    • Labels:
      None

      Description

      Packet counts reported by distribution link are either too low or too high.

      For example, the network interface reports ~3kpps TX in total, but send_cnt via erlang:port_info/2 reports 0.4pps (7500x fewer pps).

      On the same host, the network interface reports ~3kpps RX, but recv_cnt reports 16kpps (5x more).

      Furthermore, if send_cnt is 0.4pps how can send_bytes be 100MB/s ? A TCP packet cannot exceed 64K in Linux, and according to recv_cnt / recv_bytes received packets do not exceed 1.5KB (the Ethernet MTU site), but sent packets exceed 150MB...

      I've attached the relevant metrics screenshots. Will package the entire setup in Docker Compose and share so that you can reproduce locally.

      1. erl-959.tar
        107 kB
        Gerhard Lazu
      2. erl-959.tar.sha256
        0.1 kB
        Gerhard Lazu
      1. avg-inet-packet-size-explain.png
        480 kB
      2. no-tls-dist-inet-avg-packet-size-received.png
        1.46 MB
      3. no-tls-dist-inet-avg-packet-size-sent.png
        1.48 MB
      4. no-tls-dist-inet-overview.png
        1.63 MB
      5. rabbitmq-overview-tls-dist-1mb-inet-buffer.png
        1009 kB
      6. rabbitmq-overview-tls-dist-default-inet-buffer.png
        958 kB
      7. tls-dist-1mb-inet-buffer.png
        1.48 MB
      8. tls-dist-default-inet-buffer.png
        1.44 MB
      9. tls-dist-inet-avg-packet-size-vs-avg-tcp-packet-values.png
        2.16 MB
      10. tls-dist-processes-1mb-inet-buffer.png
        1.56 MB
      11. tls-dist-processes-default-inet-buffer.png
        1.70 MB

        Activity

        gerhard Gerhard Lazu created issue -
        gerhard Gerhard Lazu made changes -
        Field Original Value New Value
        Attachment erl-959.tar.sha256 [ 11339 ]
        Attachment erl-959.tar [ 11340 ]
        gerhard Gerhard Lazu made changes -
        Description Packet counts reported by distribution link are either too low or too high.

        For example, the network interface reports ~3kpps TX in total, but send_cnt via erlang:port_info/2 reports 0.4pps (7500x fewer pps).

        On the same host, the network interface reports ~3kpps RX, but recv_cnt reports 16kpps (5x more).

        Furthermore, if send_cnt is 0.4pps how can send_bytes be 100MB/s ? A TCP packet cannot exceed 64K in Linux, and according to recv_cnt / recv_bytes received packets do not exceed 1.5K (the MTU site), but sent packets exceed 150MB.

        I've attached the relevant metrics screenshots. Will package the entire setup in Docker Compose and share so that you can reproduce locally.
        Packet counts reported by distribution link are either too low or too high.

        For example, the network interface reports ~3kpps TX in total, but send_cnt via erlang:port_info/2 reports 0.4pps (7500x fewer pps).

        On the same host, the network interface reports ~3kpps RX, but recv_cnt reports 16kpps (5x more).

        Furthermore, if send_cnt is 0.4pps how can send_bytes be 100MB/s ? A TCP packet cannot exceed 64K in Linux, and according to recv_cnt / recv_bytes received packets do not exceed 1.5KB (the Ethernet MTU site), but sent packets exceed 150MB...

        I've attached the relevant metrics screenshots. Will package the entire setup in Docker Compose and share so that you can reproduce locally.
        rickard Rickard Green made changes -
        Assignee Team PS [ otp_team_ps ]
        gerhard Gerhard Lazu made changes -
        Status Open [ 1 ] Resolved [ 5 ]
        Assignee Team PS [ otp_team_ps ] Lukas Larsson [ lukas ]
        Resolution Not a Bug [ 10102 ]
        gerhard Gerhard Lazu made changes -
        Attachment Screenshot 2019-05-30 at 18.26.56.png [ 11336 ]
        gerhard Gerhard Lazu made changes -
        Attachment Screenshot 2019-05-30 at 18.26.45.png [ 11337 ]
        gerhard Gerhard Lazu made changes -
        Attachment avg-inet-packet-size-explain.png [ 11351 ]

          People

          • Assignee:
            lukas Lukas Larsson
            Reporter:
            gerhard Gerhard Lazu
          • Votes:
            0 Vote for this issue
            Watchers:
            2 Start watching this issue

            Dates

            • Created:
              Updated:
              Resolved:

              Development