Let's reduce n-body program workload 250x from N=50,000,000 to N=200,000, so runtimes are only hundredths-of-a-second.
Let's perform a series of "warm-up" calculations and measure elapsed-seconds in-process to exclude startup costs.
Similar but different: Let's perform one calculation and measure elapsed-seconds "process" to include startup costs. Let's perform one calculation and measure elapsed-seconds "in-process" to exclude startup costs. Let's perform 3,000 "warm-up" calculations and then measure elapsed-seconds in-process to exclude startup costs.