use Time::HiRes qw[ time ];
 
 
my $pattern = join "","a".."z";
 
my $str= $pattern x 1E6 . "X" .$pattern x1E6;
$\="\n";
$|=1;
 
print "Length: ",length $str;
 
print "\n---End X";
 
$start=time;
print "Match: ", $str =~/${pattern}X/;
printf "\t took %.3f sec\n",time-$start;
 
$start=time;
print "Index: ", index $str , "${pattern}X";
printf "\t took %.3f sec\n",time-$start;
 
print "\n---Start X";
 
$start=time;
print "Match: ", $str =~/X${pattern}/;
printf "\t took %.3f sec\n",time-$start;
 
$start=time;
print "Index: ", index $str , "X${pattern}";
printf "\t took %.3f sec\n",time-$start;