_Performance Testing issues_

Branch: dpdk

e7fd5a3bbe5636e93a66fd5086f182756624c97a --> performance testing fail

Test environment and result as below:

Ubuntu 18.04
Kernel: 4.15.0-generic
GCC: 7.4
NIC: Mellanox ConnectX-4 Lx 40000 Mbps
Target: x86_64-native-linuxapp-gcc
Fail/Total: 1/6

Detail performance results: 
+------------+---------+-------------------------------------+
| frame_size | txd/rxd | throughput difference from expected |
+============+=========+=====================================+
| 64         | 256     | -0.244                              |
+------------+---------+-------------------------------------+
| 128        | 256     | -1.298                              |
+------------+---------+-------------------------------------+
| 256        | 256     | -0.685                              |
+------------+---------+-------------------------------------+
| 512        | 256     | 0.045                               |
+------------+---------+-------------------------------------+
| 1024       | 256     | 0                                   |
+------------+---------+-------------------------------------+
| 1518       | 256     | -0.010                              |
+------------+---------+-------------------------------------+

https://lab.dpdk.org/results/dashboard/tarballs/5828/

UNH-IOL DPDK Performance Test Lab

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