Here I come across some weird issues regarding vapi performance. 

Reproduce :

1. Start VPP with default configuration like "systemctl restart vpp"
2.  run ` for i in {0..100}; do vppctl create loopback interface;vppctl set int state loop${i} up; done;`
3. compile the following code,see file attached, with command "g++ ./main.cpp -lboost_system -lvom -lvapiclient"
4. run ./a.out

Problems

This piece of code just wants to dump all the interfaces for like 10000 times in a while loop, if it finds no interfaces available, it breaks the loop and exit. 
 
On my laptop, it exits too early, dumps interfaces successfully only for like 495 times or so, even after I add sleep between two consecutive dumps.  Here's the weird phenomenon. The number of successful dump stays the same.