Given the parent node of your node, this might sound repetitive, but that's exactly why modules like Benchmark exist.
map{substr$_->[0],$_->[1]||0,1}[\*||{},3],[[]],[ref qr-1,-,-1],[{}],[sub{}^*ARGV,3]

I did try cmpthese but I got error messages about the input file and it wouldn't run. My code:

#!/usr/bin/perl
use strict;
use warnings;
use Benchmark 'cmpthese';
use Time::HiRes qw/tv_interval gettimeofday/;

#https://perlmonks.org/index.pl?node_id=11164097

open my $fh, '<', 'try3.txt' or die $!; # try3.txt contains the origin
+al data

my $s;

{
    local $/ = undef; #local $/ = '', is paragraph mode
    $s = <$fh>;    # slurp file
}

$s = $s x 10_000; # 90_000 lines (30_000 records)

close $fh or die $!;


sub GRT {
    my $s = shift;
    map { unpack q{x4a*}, $_ }
   sort
   map {
       m{(\d+)(?=%)}
       &&
       ( ~ pack( q{N}, $1 ) . pack( q{a*}, $_ ) )
   }
   do  {
       #local $/ = q{}; # $s is slurped before passing to split functi
+on
       split m{(?<!\A)(?=>>>)}, $s;
   }    
}

sub ST {
    my $s = shift;
    map {$_->[0]}
    sort {$b->[1] <=> $a->[1]}
    map {[$_, /(\d+)%/]} split(/^(?=>>> )/m, $s)
}

my $t0;
my $elapsed;

$t0 = [gettimeofday];
GRT($s);
$elapsed = tv_interval ( $t0, [gettimeofday]);

print "GRT time: ", $elapsed, "\n";

$t0 = [gettimeofday];
ST($s);
$elapsed = tv_interval ( $t0, [gettimeofday]);

print "ST time:  ", $elapsed;

=begin
C:\Old_Data\perlp>perl GRT_ST_transform.pl
GRT time: 0.222224
ST time:  0.05873
C:\Old_Data\perlp>
=cut

#cmpthese( -1, { 'a' => GRT($s), 'b' => ST($s) } ) ;
[download]

The input file was the 9 lines (that I expanded to 90_000 lines for the test):

>>> prd1701
Filesystem                                  Size  Used Avail Use% Moun
+ted on
/workspace                                  3.9T  887G  3.0T  13% /wor
+kspace/data
>>> prd1702
Filesystem                                  Size  Used Avail Use% Moun
+ted on
/workspace                                  3.9T  746G  3.1T  23% /wor
+kspace/data
>>> prd1703
Filesystem                                  Size  Used Avail Use% Moun
+ted on
/workspace                                  3.9T  687G  3.2T  18% /wor
+kspace/data
[download]

done