We have a requirement to read a source file, and for every row, apply some transformations and write to a output file. The code is however taking a long time approximately 25 seconds for processing a 500MB file. Please suggest if we can apply some performance improvements.

#!/usr/bin/perl
use strict;
use warnings;
use POSIX qw(strftime);
my $infile=$ARGV[0];
my $outfile=$ARGV[1];
open(DATAIN,"<$infile");
open(DATAOUT,">$outfile");
while(<DATAIN>)
{
   my($line)=$_;
   chomp($line);
   my @Fields = split(',', $line,9);
   my $X=$Fields[8];
   my $Y = substr $X,0,10;
   my $A = strftime "%M,%Y,%m,%d,%H,%j,%W,%u,%A", gmtime $Y;
   my $B = substr($A, 0, index($A, ','));
   my $C = int($B/5);
   my $D = int($B/15);
   print DATAOUT $line,",",$Y,",",$A,",",$C,",",$D,"\n";
}
close(DATAIN);
close(DATAOUT);
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