Threads vs Async

#!/usr/bin/perl
use 5.16.1;
use Thread::Pool::Simple;
use threads::shared;
use Redis;
use Time::HiRes qw(time);

use constant {
  OBJS_N=>2000,
  SLICE_N=>10,
};

my %resT :shared;
my %resS;

my $r=Redis->new;
$r->flushdb;
$r->set("s$_",int(rand(2000))) for 0..1999;
$r->quit;
undef $r;


my $pool=Thread::Pool::Simple->new(
  'min'=>4,
  'max'=>128,
  'do'=>[sub {
    return unless my @jobs=@_;
    my $r=Redis->new;
    for my $oid ( map 's'.$_, @jobs ) {
      $r->get($oid, sub { $resT{$oid}=shift })
    }
    $r->wait_all_responses
   }],
);

my @id;
my $slice=OBJS_N/SLICE_N;

my $startTick=time();
$id[$_]=$pool->add(($slice*$_)..($slice*($_+1)-1)) for 0..(SLICE_N-1);
$pool->join;
my $elapT=time()-$startTick;

say 'Estimated with threads: ', $elapT;

$startTick=time();
$r=Redis->new;
for my $oid (map 's'.$_, 0..1999) {
  $r->get($oid, sub { $resS{$oid}=shift })
}
$r->wait_all_responses;
my $elapS=time()-$startTick;

say 'Estimated with async-only: '.$elapS;