fizzbuzz

Optimisation of classic FizzBuzz test.

supernaive

The least efficient implementation, with 3 ifs and two printfs per number. It is so inefficient that I don't even use it for comparison.

naive

A little bit optimised version, with 2 ifs (not counting the loop condition) and 1 printf per number.

unrolled

Single loop iteration for 15 numbers, it means for 15 numbers just one branch (vs 45 branches for naive) and 1 printf (vs 15 printfs for naive).

customprint

Generic printf replaced with custom print routine, tailored for this particular task.

reusebuf

Reuse buffer from previous iteration, update only the changed characters. Use x86_64 vector instructions for comparing buffers.

multithreaded

Use worker threads to process the sets of numbers in parallel.

Comparison

All tests are performed on Dell Latitude 7480 with Core i7-7600U (2 cores with hyperthreading) and 16 Gb RAM, OpenSUSE Leap 15.1, kernel 4.12.14. Output redirected to /dev/null. Multithreaded implementation uses 4 worker threads, with load of 3M number per thread.