Low Throughput on Mellanox connectx-C6

[ATsupport qa]

Hi Team,

Facing low throughput issue with trex. Have some queries regarding the traffic generation. Appreciate, if you could help resolving the issues and give some proper understanding of trex.

We are trying to generate traffic using an internet captured PCAP using the Push command in stateless mode.
The Nic Card used is Mellanox "MT28908 Family [ConnectX-6]" . 2 port is connected each of 40 Gbps .
The traffic throughput is just around 1.5Gbps per port.

Trex_cfg.yaml file is

### Config file generated by dpdk_setup_ports.py ###

- version: 2
  interfaces: ['interface','dummy','interface','dummy']
  port_info:
#  CU worker1 Mellanox
      - dest_mac: dst_mac_address
        src_mac:  src_mac_address
      - dest_mac: dst_mac_address
        src_mac:  src_mac_address
      - dest_mac: dst_mac_address
        src_mac:  src_mac_address
      - dest_mac: dst_mac_address
        src_mac:  src_mac_address
     

  platform:
      master_thread_id: 0
      latency_thread_id: 21
      dual_if:
        - socket: 1
          threads: [2,3]
        - socket: 1
          threads: [10,11]
        - socket: 1
          threads: [12,13]
        - socket: 1
          threads: [15,16]

Command Used:
/t-rex-64 -i              <<server
/trex-console             <<console
push -i 7 -s 10 -r -c 0 -f /path_to_pcap/pcap_file.pcap

output:
-Per port stats table
      ports |               0 |               2
 -----------------------------------------------------------------------------------------
   opackets |       130212429 |       133105638
     obytes |     66793877779 |     68521657826
   ipackets |              19 |              19
     ibytes |            6574 |            6574
    ierrors |               0 |               0
    oerrors |               0 |               0
      Tx Bw |       1.54 Gbps |       1.44 Gbps

-Global stats enabled
 Cpu Utilization : 100.0  %  3.0 Gb/core
 Platform_factor : 1.0
 Total-Tx        :       2.98 Gbps
 Total-Rx        :       0.00  bps
 Total-PPS       :     589.78 Kpps
 Total-CPS       :       0.00  cps

 Expected-PPS    :       0.00  pps
 Expected-CPS    :       0.00  cps
 Expected-BPS    :       0.00  bps

 Active-flows    :        0  Clients :        0   Socket-util : 0.0000 %
 Open-flows      :        0  Servers :        0   Socket :        0 Socket/Clients :  -nan
 Total_queue_full : 676559200                                               <<<<<<<<< Queue is full
 drop-rate       :       2.98 Gbps                                          <<<<<<<<< drop
 current time    : 403.3 sec
 test duration   : 0.0 sec

1. Is there a different way to run traffic , if the Pcap used is of huge say more than 7 or 8 Gbps. The method used here is incorrect ? 
2. Trex requires any specific configuration for The Mellonox card to get the required throughput. Is there any pre-requisite for Mellanox connectX-c6 with trex in stateless mode?
3. When pcap is used, does trex requires any specific configuration depending on traffic. For instance, if the traffic is GRE , no-gre, GTP etc.?
4. CPU utilization is 100% with just 3gbps of traffic, Also the Total Queue full is increasing along with the drop rate. is this the reason for the low throughput. What does these attributes describe.
5. Does trex have any log file generated. what would be the path of the file.