diff --git a/benchmark/benchmark.php b/benchmark/benchmark.php
index 0c2ac4c6010a4..787845f74bcc6 100644
--- a/benchmark/benchmark.php
+++ b/benchmark/benchmark.php
@@ -2,11 +2,7 @@
 
 require_once __DIR__ . '/shared.php';
 
-foreach (array("mbstring", "sockets", "mysqli", "openssl", "gmp") as $ext) {
-    if (!extension_loaded($ext)) {
-        throw new LogicException("Extension $ext is required.");
-    }
-}
+checkExtensions(['gmp']);
 
 $storeResult = ($argv[1] ?? 'false') === 'true';
 $phpCgi = $argv[2] ?? dirname(PHP_BINARY) . '/php-cgi';
@@ -27,12 +23,18 @@ function main() {
     if (false !== $branch = getenv('GITHUB_REF_NAME')) {
         $data['branch'] = $branch;
     }
+
     $data['Zend/bench.php'] = runBench(false);
     $data['Zend/bench.php JIT'] = runBench(true);
+
+    checkExtensions(['mbstring']);
     $data['Symfony Demo 2.2.3'] = runSymfonyDemo(false);
     $data['Symfony Demo 2.2.3 JIT'] = runSymfonyDemo(true);
+
+    checkExtensions(['mbstring', 'sockets', 'mysqli', 'openssl']);
     $data['Wordpress 6.2'] = runWordpress(false);
     $data['Wordpress 6.2 JIT'] = runWordpress(true);
+
     $result = json_encode($data, JSON_PRETTY_PRINT) . "\n";
 
     fwrite(STDOUT, $result);
@@ -42,6 +44,14 @@ function main() {
     }
 }
 
+function checkExtensions(array $extensions): void {
+    foreach ($extensions as $ext) {
+        if (!extension_loaded($ext)) {
+            throw new LogicException("Extension $ext is required.");
+        }
+    }
+}
+
 function storeResult(string $result) {
     $repo = __DIR__ . '/repos/data';
     cloneRepo($repo, 'git@github.com:php/benchmarking-data.git');
@@ -136,6 +146,9 @@ function runValgrindPhpCgiCommand(
     return ['instructions' => $instructions];
 }
 
+/**
+ * @return decimal-int-string
+ */
 function extractInstructionsFromValgrindOutput(string $output): string {
     preg_match("(==[0-9]+== Events    : Ir\n==[0-9]+== Collected : (?<instructions>[0-9]+))", $output, $matches);
     return $matches['instructions'] ?? throw new \Exception('Unexpected valgrind output');
diff --git a/benchmark/shared.php b/benchmark/shared.php
index 0f58a2a1bf870..107e097fb176c 100644
--- a/benchmark/shared.php
+++ b/benchmark/shared.php
@@ -1,14 +1,15 @@
 <?php
 
-class ProcessResult {
-    public $stdout;
-    public $stderr;
+readonly class ProcessResult {
+    public function __construct(
+        public string $stdout,
+        public string $stderr,
+    ) {}
 }
 
 function runCommand(array $args, ?string $cwd = null, bool $printCommand = true): ProcessResult {
     $cmd = implode(' ', array_map('escapeshellarg', $args));
     $pipes = null;
-    $result = new ProcessResult();
     $descriptorSpec = [0 => ['pipe', 'r'], 1 => ['pipe', 'w'], 2 => ['pipe', 'w']];
     if ($printCommand) {
         fwrite(STDOUT, "> $cmd\n");
@@ -24,6 +25,8 @@ function runCommand(array $args, ?string $cwd = null, bool $printCommand = true)
     stream_set_blocking($stdout, false);
     stream_set_blocking($stderr, false);
 
+    $stdoutStr = '';
+    $stderrStr = '';
     $stdoutEof = false;
     $stderrEof = false;
 
@@ -37,9 +40,9 @@ function runCommand(array $args, ?string $cwd = null, bool $printCommand = true)
         foreach ($read as $stream) {
             $chunk = fgets($stream);
             if ($stream === $stdout) {
-                $result->stdout .= $chunk;
+                $stdoutStr .= $chunk;
             } elseif ($stream === $stderr) {
-                $result->stderr .= $chunk;
+                $stderrStr .= $chunk;
             }
         }
 
@@ -50,6 +53,8 @@ function runCommand(array $args, ?string $cwd = null, bool $printCommand = true)
     fclose($stdout);
     fclose($stderr);
 
+    $result = new ProcessResult($stdoutStr, $stderrStr);
+
     $statusCode = proc_close($processHandle);
     if ($statusCode !== 0) {
         fwrite(STDOUT, $result->stdout);