Track how long a thread spent actually working on a future

Question

I would like to keep track of how long a thread in a ThreadPoolExecutor spend working on a piece of code that I submitted to the pool, not how long the work item spent sitting in the pool. I, of course, call future.result() to get the result, but I was hoping there was some way I could call future.time() or something like that to get the execution time. Any suggestions?

Answer 1

I would write a simple wrapper that does this:

def timed(func):
    def _w(*a, **k):
        then = time.time()
        res = func(*a, **k)
        elapsed = time.time() - then
        return elapsed, res
    return _w

Then you invoke your future e.g. with executor.map(timed(is_prime), PRIMES)) (example taken from the docs).

Of course then you need to unpack the resulting timestamp & result

elapsed, result = future.result()