An option is to use perl's nested hash. The keys would be your start time / end time and other important tokens, with their values assigned according to the logic in your perl script. this is what first got me hooked to perl.:D

  1 #!/usr/bin/perl
  2 
  3 %process_hash = (
  4   'pid_1' => {
  5     'start_time' => '00:00:00',
  6     'end_time' => '12:00:00'
  7     },
  8   'pid_2' => {
  9     'start_time' => '00:00:01',
 10     'end_time' => '12:00:02'
 11     }
 12 );
 13 
 14 print $process_hash{'pid_2'}->{'start_time'};
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please check perlvar,perldata and perlreftut for further info.