$^T is far too coarse for yoru kind of measurement, as it measures whole seconds only.

If you want to measure compilation time, you can try something like this — put it near the very top of your script: 

use Time::HiRes;
my $t0;
BEGIN {
    $t0 = Time::HiRes::time;
}
my $t1 = Time::HiRes::time;
printf STDERR "Compilation time: %.3f seconds\n", $t1-$t0;

[download]

$t0 is set in the BEGIN block, at the start of the compilation cycle. $t1 is set when the script actually starts to run, thus after compilation is complete. Next it prints out the difference, in fractions of seconds.

This will still miss the startup time of perl itself.

In reply to Re: measuring startup time: how early does $^T (start time of program) get set? by bart
in thread measuring startup time: how early does $^T (start time of program) get set? by blahblahblah

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.