Main example may take abnormal time

[chuqingq]

~/temp/dpdk-rte_ring $ ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 14011110 ns
dequeue total: 50000, sum: 249975000
~/temp/dpdk-rte_ring $ ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 14052456 ns
dequeue total: 50000, sum: 249975000
~/temp/dpdk-rte_ring $ ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13765569 ns
dequeue total: 50000, sum: 249975000
~/temp/dpdk-rte_ring $ ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 70299109713 ns
dequeue total: 50000, sum: 249975000

~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13734627 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 14341767 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13951518 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13868262 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13748691 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.022s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13561638 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13700562 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13373007 ns
dequeue total: 50000, sum: 249975000

real 0m0.028s
user 0m0.062s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 13959600 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.023s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 15546474 ns
dequeue total: 50000, sum: 249975000

real 0m0.013s
user 0m0.020s
sys 0m0.003s
~/temp/dpdk-rte_ring $ time ./main
start enqueue, 5 producer threads, echo thread enqueue 10000 numbers.
start dequeue, 1 consumer thread, dequeue 50000 numbers
time diff: 209055734802 ns
dequeue total: 50000, sum: 249975000

real 1m17.457s
user 4m57.134s
sys 0m0.621s