use Time::HiRes qw( time );

# ordered insert
$insertDurationSum = 0.0;
@insertDurationMeas = ();
for ($n = 10; $n > 0; $n--) {
    $start = time();
    my %ht = ();
    for ($i = 10000000; $i > 0; $i--) {
        $ht{$i} = $i + $n + 0.0;
    }
    $end = time();
    $duration = $end - $start;
    $insertDurationSum += $duration;
    push(@insertDurationMeas, $duration);
    print "$n\n";
}
# find adjustment
$start = time();
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $x = $i + 3.0;
}
$end = time();
$adjustment = $end - $start;
# report on timing
$mean = $insertDurationSum/10.0;
$durationVar = 0.0;
foreach $v (@insertDurationMeas) {
    $durationVar += ($v-$mean)*($v-$mean);
}
$stdv = sqrt($durationVar/10.0);
printf("insert timing (ordered) in seconds: mean %.2f, adj-mean %.2f, stdv %.2f\n", $mean, $mean - $adjustment, $stdv);
# lookup test
$start = time();
$lfsr = 1;
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
    $x += $ht{$lfsr}
}
$end = time();
$lookupDuration = $end - $start;
# find adjustment
$start = time();
$lfsr = 1;
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
    $x += $i
}
$end = time();
$adjustment = $end - $start;
printf("lookup timing (mostly misses) in seconds: %.2f, adj %.2f\n", $lookupDuration, $lookupDuration-$adjustment);

# unordered insert
$insertDurationSum = 0.0;
@insertDurationMeas = ();
for ($n = 10; $n > 0; $n--) {
    $start = time();
    my %ht = ();
    $lfsr = 1;
    for ($i = 10000000; $i > 0; $i--) {
        $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
        $ht{$lfsr} = $i + $n + 0.0;
    }
    $end = time();
    $duration = $end - $start;
    $insertDurationSum += $duration;
    push(@insertDurationMeas, $duration);
    print "$n\n";
}
# find adjustment
$start = time();
$lfsr = 1;
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
    $x = $i + 3.0
}
$end = time();
$adjustment = $end - $start;
# report on timing
$mean = $insertDurationSum/10.0;
$durationVar = 0.0;
foreach $v (@insertDurationMeas) {
    $durationVar += ($v-$mean)*($v-$mean);
}
$stdv = sqrt($durationVar/10.0);
printf("insert timing (unordered) in seconds: mean %.2f, adj-mean %.2f, stdv %.2f\n", $mean, $mean - $adjustment, $stdv);
# lookup test
$start = time();
$lfsr = 1;
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
    $x += $ht{$lfsr}
}
$end = time();
$lookupDuration = $end - $start;
# find adjustment
$start = time();
$lfsr = 1;
$x = 0.0;
for ($i = 10000000; $i > 0; $i--) {
    $lfsr = ($lfsr >> 1) ^ (0 - ($lfsr & 1) & 0xd0000001);
    $x += $i;
}
$end = time();
$adjustment = $end - $start;
printf("lookup timing (no misses) in seconds: %.2f, adj %.2f\n", $lookupDuration, $lookupDuration-$adjustment);