Kong Performance - Throughput remains constant

Team,

I am trying to performance test kong gateway. While doing so I am have 100 users as the initial count and getting close to 6000 ps and a very good response time from KONG. However when I increase the number of user say 200 I assume that the kong’s throughput should increase, but I do not see this to be the case. I still stays in the same 6000tps.
My assumption is that there is something like a max threads that can handle no more than 6000tps , if yes do we know what that setting is and can we modify that?

Appreciate your reply on this!