How do I use Igor Pavlov timer for a Bash script ?

[abd]

I want to measure the time used as I run a Bash script 'd' that'd do compressing and directory listing far better if being automated. So how for me to use Igor Pavlov's timer.exe to obtain the execution-time of that Bash script ?
Many thanks in advance.

[schnaader]

"Bash script" sounds like you're going to use Linux, which has a "time" command that can measure the time of a command execution, so I'd prefer this way. If you really want to use timer.exe on a Linux system, you'd have to use wine to execute the Windows binary timer.exe to measure Linux commands, I'm pretty sure this won't work.

If you meant "batch script" instead (Windows script), just call "timer mybatch.bat" or use "timer" inside of the batch.

[JamesB]

On linux I prefer to use google perftools as it can give much more information, including important things like clock speed variations.

@ seq3a[/tmp]; perf stat gzip enwik8

 Performance counter stats for 'gzip enwik8':

       7418.784633 task-clock                #    0.997 CPUs utilized          
               626 context-switches          #    0.000 M/sec                  
                 0 CPU-migrations            #    0.000 M/sec                  
               269 page-faults               #    0.000 M/sec                  
       16264693567 cycles                    #    2.192 GHz                     [83.31%]
        8801104276 stalled-cycles-frontend   #   54.11% frontend cycles idle    [83.37%]
        6272475913 stalled-cycles-backend    #   38.56% backend  cycles idle    [66.63%]
       19361014083 instructions              #    1.19  insns per cycle        
                                             #    0.45  stalled cycles per insn [83.31%]
        3888002759 branches                  #  524.075 M/sec                   [83.41%]
         144395301 branch-misses             #    3.71% of all branches         [83.33%]

       7.439664200 seconds time elapsed

@ seq3a[/tmp]; gunzip enwik8.gz
@ seq3a[/tmp]; perf stat gzip enwik8

 Performance counter stats for 'gzip enwik8':

       6459.695532 task-clock                #    0.998 CPUs utilized          
               547 context-switches          #    0.000 M/sec                  
                 0 CPU-migrations            #    0.000 M/sec                  
               269 page-faults               #    0.000 M/sec                  
       17658879966 cycles                    #    2.734 GHz                     [83.35%]
       10214032205 stalled-cycles-frontend   #   57.84% frontend cycles idle    [83.31%]
        7496824886 stalled-cycles-backend    #   42.45% backend  cycles idle    [66.65%]
       19356436112 instructions              #    1.10  insns per cycle        
                                             #    0.53  stalled cycles per insn [83.35%]
        3885518453 branches                  #  601.502 M/sec                   [83.37%]
         144184551 branch-misses             #    3.71% of all branches         [83.33%]

       6.475480539 seconds time elapsed

This system has automatic cpu frequency scaling enabled in the bios, which makes timings a complete nightmare. The elapsed and CPU time reported by "time" is highly variable, but we see from perf that the number of instructions is the same. Cycles still differs a bit (8.6% variation between 2 runs), but this is much lower than the CPUs variation (15%). I can run it a few times until I see CPU MHz has stabilised, which gives me more confidence the answer is correct. The next two goes I got:

 Performance counter stats for 'gzip enwik8':

       5560.004486 task-clock                #    0.998 CPUs utilized          
               472 context-switches          #    0.000 M/sec                  
                 3 CPU-migrations            #    0.000 M/sec                  
               269 page-faults               #    0.000 M/sec                  
       16309805185 cycles                    #    2.933 GHz                     [83.33%]
        8850957237 stalled-cycles-frontend   #   54.27% frontend cycles idle    [83.36%]
        6365518735 stalled-cycles-backend    #   39.03% backend  cycles idle    [66.67%]
       19354319475 instructions              #    1.19  insns per cycle        
                                             #    0.46  stalled cycles per insn [83.33%]
        3887668162 branches                  #  699.220 M/sec                   [83.36%]
         144299232 branch-misses             #    3.71% of all branches         [83.32%]

       5.572425708 seconds time elapsed

@ seq3a[/tmp]; perf stat gzip enwik8

 Performance counter stats for 'gzip enwik8':

       5617.336945 task-clock                #    0.998 CPUs utilized          
               477 context-switches          #    0.000 M/sec                  
                 2 CPU-migrations            #    0.000 M/sec                  
               269 page-faults               #    0.000 M/sec                  
       16751214185 cycles                    #    2.982 GHz                     [83.30%]
        9285739462 stalled-cycles-frontend   #   55.43% frontend cycles idle    [83.32%]
        6746852365 stalled-cycles-backend    #   40.28% backend  cycles idle    [66.65%]
       19344892064 instructions              #    1.15  insns per cycle        
                                             #    0.48  stalled cycles per insn [83.36%]
        3886052970 branches                  #  691.796 M/sec                   [83.39%]
         144311360 branch-misses             #    3.71% of all branches         [83.37%]

       5.629982425 seconds time elapsed

I could do that with straight "time" of course, but it's nice to know *why* the variation is happening.