Bench php7 encapsed strings optimization

bench_concat_vs_interpol.php

<?php

// https://blog.blackfire.io/php-7-performance-improvements-encapsed-strings-optimization.html

class Foobar
{
    public function getVal1()
    {
        return rand(0, 1000);
    }

    public function getVal2()
    {
        return rand(1000, 2000);
    }
}

function str_concat($n, $obj) {
    $data = '';
    for ($i = 0; $i < $n; ++$i) {
        $data .= $obj->getVal1();
        $data .= $obj->getVal2();
    }
}

function str_interpol($n, $obj) {
    $data = '';
    for ($i = 0; $i < $n; ++$i) {
        $data = "$data{$obj->getVal1()}{$obj->getVal2()}";
    }
}

function str_interpol2($n, $obj) {
    $data = '';
    for ($i = 0; $i < $n; ++$i) {
        $data .= "{$obj->getVal1()}{$obj->getVal2()}";
    }
}


function empty_loop($n) {
    for ($i = 0; $i < $n; ++$i) {
    }
}

function getmicrotime()
{
    $t = gettimeofday();

    return ($t['sec'] + $t['usec'] / 1000000);
}

function start_test()
{
    ob_start();

    return getmicrotime();
}

function end_test($start, $name, $overhead = null)
{
    global $total;
    global $last_time;

    $end = getmicrotime();
    ob_end_clean();
    $last_time = $end-$start;
    $total += $last_time;
    $num = number_format($last_time,3);
    $pad = str_repeat(" ", 30 - strlen($name) - strlen($num));

    if (is_null($overhead)) {
        echo $name.$pad.$num."\n";
    } else {
        $num2 = number_format($last_time - $overhead, 3);
        echo $name.$pad.$num."    ".$num2."\n";
    }
    ob_start();

    return getmicrotime();
}


$total = $last_time = 0;
$obj = new Foobar();

$n = 200000;
$t = start_test();

empty_loop($n);
$t = end_test($t, "empty_loop($n)");
$overhead = $last_time;

str_concat($n, $obj);
$t = end_test($t, "str_concat($n)", $overhead);

str_interpol($n, $obj);
$t = end_test($t, "str_interpol($n)", $overhead);

str_interpol2($n, $obj);
$t = end_test($t, "str_interpol2($n)", $overhead);

output

$ php bench_concat_vs_interpol.php
empty_loop(200000)       0.002
str_concat(200000)       0.074    0.072
str_interpol(200000)    11.937    11.935
str_interpol2(200000)    0.073    0.071

$ php bench_concat_vs_interpol.php
empty_loop(200000)       0.002
str_concat(200000)       0.074    0.072
str_interpol(200000)    10.965    10.963
str_interpol2(200000)    0.077    0.075

$ php bench_concat_vs_interpol.php
empty_loop(200000)       0.002
str_concat(200000)       0.077    0.075
str_interpol(200000)     9.944    9.942
str_interpol2(200000)    0.075    0.073

$ php -v
PHP 7.1.0 (cli) (built: Dec 20 2016 17:28:16) ( NTS )
Copyright (c) 1997-2016 The PHP Group
Zend Engine v3.1.0-dev, Copyright (c) 1998-2016 Zend Technologies