Some processors expose performance counters but you don't need to accurately measure memory bandwidth to know you are maxing out. Suppose you know that the memo

Some processors expose performance counters but you don't need to accurately measure memory bandwidth to know you are maxing out. Suppose you know that the memory bandwidth is 1Gb/s and you program reads 100Gb of data to produce the result. If the execution takes ~100s then you know you hit the maximum memory bandwidth.