Concurrent Hashmap Performance

[Mohammad Motamedi]

I am trying to measure the performance of ConcurrentHashMap. I use 12 threads for concurrent insertion and lookup. The elapsed time for a few experiments is reported below:

Key Type: int -- Value Type: int -- Number of insertion: 134217728 elems, time for all insertions: 27829 ms. 

Key Type: int -- Value Type: int -- Number of look ups: 134217728 elems, time for all look ups: 4855 ms. 

I use 12 concurrent threads and my processor is: Intel(R) Core(TM) i7-7800X CPU @ 3.50GHz.

I am wondering if this is the performance that one might expect to get from ConcurrentHashMap. Any insight is greatly appreciated.