─❯ ./benchmark                                                         
2020-11-04T14:08:48+01:00
Running ./benchmark
Run on (8 X 4200 MHz CPU s)
CPU Caches:
  L1 Data 32 KiB (x4)
  L1 Instruction 32 KiB (x4)
  L2 Unified 256 KiB (x4)
  L3 Unified 8192 KiB (x1)
Load Average: 0.84, 0.89, 0.75
***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead.
-----------------------------------------------------------
Benchmark                 Time             CPU   Iterations
-----------------------------------------------------------
BM_log2_table           262 ns          262 ns      2423124
BM_log2_builtin        64.0 ns         64.0 ns     10404602
BM_log2_validate        308 ns          308 ns      2610690

Results with `-O3`: ```bash ─❯ ./benchmark 2020-11-04T14:08:48+01:00 Running ./benchmark Run on (8 X 4200 MHz CPU s) CPU Caches: L1 Data 32 KiB (x4) L1 Instruction 32 KiB (x4) L2 Unified 256 KiB (x4) L3 Unified 8192 KiB (x1) Load Average: 0.84, 0.89, 0.75 ***WARNING*** CPU scaling is enabled, the benchmark real time measurements may be noisy and will incur extra overhead. ----------------------------------------------------------- Benchmark Time CPU Iterations ----------------------------------------------------------- BM_log2_table 262 ns 262 ns 2423124 BM_log2_builtin 64.0 ns 64.0 ns 10404602 BM_log2_validate 308 ns 308 ns 2610690 ```