#!/usr/bin/perl 

use warnings;
use strict;

use Date::Manip;

my $infile = 'file';

open FH, $infile or die "$infile: $!";

my ( $sdate, $edate, $delta, $err, $ustart, $uend, $rtime );

while (<FH>) {
    if (/SvcName: CO/) {
        /Start -/ and ( $sdate = ( split ',' )[0] ) =~ s|:(.*?):|/$1/|;
        /End -/   and ( $edate = ( split ',' )[0] ) =~ s|:(.*?):|/$1/|;
    }
    if ( $sdate && $edate ) {
        $ustart = UnixDate( $sdate, "%s" );
        $uend   = UnixDate( $edate, "%s" );
        if ($edate) {
            $rtime = $ustart - $uend;
            print $sdate, " - ", $edate, "\n";
            print DateCalc( $sdate, $edate, \$err ), "\n";
        }
    }
}

% cat file
2009:04:03 08:21:41:513,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,Start - SvcName: OIS - EndUserName: - RequestId: null20090403082313
2009:04:03 08:21:41:775,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,End - SvcName: OIS - EndUserName: - RequestId: null20090403082313 - StatusCode: 0 - StatusText: Success
2009:04:03 08:21:45:660,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,Start - SvcName: VCC - EndUserName: - RequestId: 411111111111111120090403082318
2009:04:03 08:21:46:171,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,End - SvcName: VCC - EndUserName: - RequestId: 411111111111111120090403082318 - StatusCode: 0 - StatusText: Success
2009:04:03 08:21:49:583,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,Start - SvcName: CO - EndUserName: - RequestId: 20090403082321
2009:04:03 08:22:03:571,INFO ,servername,yyyy,undefined,,INFO,null,.....Out:xxService,End - SvcName: CO - EndUserName: - RequestId: 20090403082321 - StatusCode: 0 - StatusText: Success
zsh-4.3.9[t]% ./s       
2009/04/03 08:21:49:583 - 2009/04/03 08:22:03:571
+0:0:0:0:0:0:14