Run a script multiple times and store the running time

[Anonymous Monk]

Dear Monks,
I was wondering if I could get your valuable help on this matter : I have a perl script that I need to run 1000 times and for each run I need to store how much time it took to run (using, for example, the time command in Unix.
What I was thinking to do is to create a file with 1000 commands, like:

time perl script.pl ARG1 
time perl script.pl ARG2
....
time perl script.pl ARG1000

but I do not know how I can save the output of the time command somehow so that I can see it afterwards, that for running the script with the argument ARG1 it took say 1 min, then for ARG2 took 2 mins etc.
Any help would be grately appreciated!

[BrowserUk]

How about:

#! perl -slw
use strict;
use Time::HiRes qw[ time ];

while( my $arg = <DATA> ) {
    my $start = time;
    system "perl script.pl $arg";
    printf "With '%s' took: %.3f seconds\n", $arg, $time() - $start;
}
__DATA__
1000 args here 
...
...

[Anonymous Monk]

Just a minor correction here (I hope no offence is taken):
It seems that :
 printf "With '%s' took: %.3f seconds\n", $arg, $time() - $start;
should instead be:
printf "With '%s' took: %.3f seconds\n", $arg, time() - $start;

[Anonymous Monk]

Aha, I will give it a try!
Thank you!

[ww]

Alternate approach but leaving the complexities that would cause varying execution times for the tested script, foo_a.pl (that's left as the proverbial challenge for the OP). Note also the caveat at LN9 of the script immediately below:

#!/usr/bin/perl -w
use strict;

use Time::HiRes qw[ time ];

# OP: "I have a perl script that I need to run 1000 times and for each
+ run 
#      I need to store how much time it took to run... "
# using foo_a.pl, execute this from foo_a's dir
# Timings of foo_a.pl are NOT precise because they include the time 
# to execute the calculations here.

my $begin = time;
for my $arg( 1..1000 ) {
    my $start = time;
    system "perl foo_a.pl $arg";
    my $duration = (time - $start);
    print "\n\t\$arg: $arg, \t\$start: $start, \t\$duration: $duration
+\n";
    $start = time;
}

print "$begin" . time . "\n";
exit;

foo_a.pl, an (almost) empty script:

#! /usr/bin/perl -w
use strict;

#foo_a.pl

print "--foo_a.pl's marker inserted when run at LN11 in 1173964_a.pl: 
+";
exit;

And the output of D:\_Perl_\PMonks>D:\_Perl_\PMonks\1173964_a.pl > 1173964_a_OUT.pl on (Win7, AS 5.18), edited as noted:

--foo_a.pl's marker inserted when run at LN11 in 1173964_a.pl: 
    $arg: 1,     $start: 1476409956.16692,     $duration: 0.0165810585
+021973
--foo_a.pl's marker inserted when run at LN11 in 1173964_a.pl: 
    $arg: 2,     $start: 1476409956.18353,     $duration: 0.0134079456
+329346
--foo_a.pl's marker inserted when run at LN11 in 1173964_a.pl: 
    $arg: 3,     $start: 1476409956.19695,     $duration: 0.0137300491
+333008
--foo_a.pl's marker inserted when run at LN11 in 1173964_a.pl: 
    $arg: 4,     $start: 1476409956.2107,     $duration: 0.01424980163
+57422

# elided for brevity and henceforward, "marker inserted" lines deleted
+:

    $arg: 495,     $start: 1476409962.28221,     $duration: 0.01291704
[phone]
    $arg: 496,     $start: 1476409962.29514,     $duration: 0.01339387
[phone]
    $arg: 497,     $start: 1476409962.30855,     $duration: 0.01174592
[phone]
    $arg: 498,     $start: 1476409962.32031,     $duration: 0.01395082
[phone]
    $arg: 499,     $start: 1476409962.33427,     $duration: 0.01355600
[phone]
    $arg: 500,     $start: 1476409962.34784,     $duration: 0.01249790
[phone]
    $arg: 501,     $start: 1476409962.36035,     $duration: 0.01373386
[phone]
    $arg: 502,     $start: 1476409962.3741,     $duration: 0.012020826
+3397217
    $arg: 503,     $start: 1476409962.38613,     $duration: 0.01191496
[phone]
    $arg: 504,     $start: 1476409962.39807,     $duration: 0.01241683
[phone]
    $arg: 505,     $start: 1476409962.4105,     $duration: 0.012879133
+2244873

# another long stretch omitted...

    $arg: 995,     $start: 1476409968.50899,     $duration: 0.01135301
[phone]
    $arg: 996,     $start: 1476409968.52035,     $duration: 0.01180887
[phone]
    $arg: 997,     $start: 1476409968.53218,     $duration: 0.01137590
+4083252
    $arg: 998,     $start: 1476409968.54356,     $duration: 0.01149606
[phone]
    $arg: 999,     $start: 1476409968.55507,     $duration: 0.01226401
[phone]
    $arg: 1000,     $start: 1476409968.56735,     $duration: 0.0137550
[phone]

NB: initial "begin time": 1476409956.16692; time completed: 1476409968.58113 or roughly 12 seconds for 1000 iterations of foo_a.pl measured this way ... and yes, I see the command line is unnecessarily redundant... but so (perhaps) is this node.

[Laurent_R]

Just a wild guess from looking at your question: perhaps what you're really looking for is a module such as Benchmark.