Hi, I am using Time:HiRes module. I just measuring the before and after time as shown in the script below. However, in many cases the "after time" comes out less than "before time", when I run it on Windows with multi-core CPU's. I don't get this when I am running the below script on a VM which has Linux with only one processor allocated to it. Why could this be happening? 
#!/usr/bin/perl -w


use Time::HiRes;


$count = 1000000; print "\nStarting loop\n";
for ($c = $count; $c >= 1; $c--)
{
   
   $t3 = 0; $t4 =0; $t5 = 0;  

   #print "\n";
   #print "t3: "; printf "%.2f\n",$t3;
   #print "t4: "; printf "%.2f\n",$t4;
   #print "\n";

  

   $t3 = Time::HiRes::time();  
    
   $t4 = Time::HiRes::time();
 
   $t5 = $t4-$t3;

   #print "t5: "; printf "%.6f\n",$t5;

   if($t5<=0)
   {
        print"\n Value negative in count: $c";
        print "\n t3: "; printf "%.6f",$t3;
        print "\n t4: "; printf "%.6f\n",$t4;
       print "\n Negative or zero value: $t5";
   }
 

}
print "\nEnd of loop\n";

[download]

In reply to negative elapsed time? by saneel

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.