Usage Profiling and benchmarking

/usr/bin/time ¹⁾ can report total run time (“clock on the wall”) and memory (RSS = Resident Set Size)

/usr/bin/time -v perl -e '"a"x(1024**3);' |& grep -Pi 'max|wall'
#        Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.40
#        Maximum resident set size (kbytes): 1053908

When run with slurm, eg. Pittsburgh Super Computer

 sacct -j $jobid --format=JobID,MaxRSS,AveRSS,TotalCPU,Elapsed

For smaller jobs, hyperfine runs many time for a more rigorous estimate.

hyperfine 'sleep .5' 'sleep .55'

Benchmark 1: sleep .5
  Time (mean ± σ):     502.3 ms ±   0.6 ms    [User: 1.6 ms, System: 0.8 ms]
  Range (min … max):   501.7 ms … 503.2 ms    10 runs
 
Benchmark 2: sleep .55
  Time (mean ± σ):     552.6 ms ±   0.5 ms    [User: 1.5 ms, System: 1.0 ms]
  Range (min … max):   551.8 ms … 553.4 ms    10 runs
 
Summary
  sleep .5 ran
    1.10 ± 0.00 times faster than sleep .55