diff --git a/src/Psalm/Internal/Cli/Psalm.php b/src/Psalm/Internal/Cli/Psalm.php
index 43b8afe5f81..98c16d5c23a 100644
--- a/src/Psalm/Internal/Cli/Psalm.php
+++ b/src/Psalm/Internal/Cli/Psalm.php
@@ -431,8 +431,8 @@ public static function getThreads(array $options, Config $config, bool $in_ci, b
         }
 
         if ($for_scan) {
-            if (isset($options['scanThreads'])) {
-                $threads = max(1, (int)$options['scanThreads']);
+            if (isset($options['scan-threads'])) {
+                $threads = max(1, (int)$options['scan-threads']);
             } elseif (isset($options['debug']) || $in_ci) {
                 $threads = 1;
             } elseif ($config->scan_threads) {
diff --git a/src/Psalm/Internal/Fork/ForkContext.php b/src/Psalm/Internal/Fork/ForkContext.php
index 2e08fc1f952..1a10ddef811 100644
--- a/src/Psalm/Internal/Fork/ForkContext.php
+++ b/src/Psalm/Internal/Fork/ForkContext.php
@@ -13,6 +13,7 @@
 use Amp\Parallel\Context\Internal\ExitFailure;
 use Amp\Parallel\Context\Internal\ExitSuccess;
 use Amp\Parallel\Ipc\IpcHub;
+use Amp\Serialization\NativeSerializer;
 use Amp\Serialization\SerializationException;
 use Amp\TimeoutCancellation;
 use Error;
@@ -25,6 +26,7 @@
 use function Amp\Parallel\Ipc\connect;
 use function count;
 use function define;
+use function extension_loaded;
 use function fwrite;
 use function is_file;
 use function is_string;
@@ -63,6 +65,10 @@ public static function start(
         ?Cancellation $cancellation = null,
         int $childConnectTimeout = self::DEFAULT_START_TIMEOUT,
     ): self {
+        $serializer = extension_loaded('igbinary')
+            ? new IgbinarySerializer
+            : new NativeSerializer;
+
         $key = $ipcHub->generateKey();
 
         // Fork
@@ -74,10 +80,10 @@ public static function start(
         if ($pid > 0) {
             try {
                 $socket = $ipcHub->accept($key, $cancellation);
-                $ipcChannel = new StreamChannel($socket, $socket);
+                $ipcChannel = new StreamChannel($socket, $socket, $serializer);
         
                 $socket = $ipcHub->accept($key, $cancellation);
-                $resultChannel = new StreamChannel($socket, $socket);
+                $resultChannel = new StreamChannel($socket, $socket, $serializer);
             } catch (Throwable $exception) {
                 $cancellation?->throwIfRequested();
         
@@ -98,10 +104,10 @@ public static function start(
 
         try {
             $socket = connect($uri, $key, $connectCancellation);
-            $ipcChannel = new StreamChannel($socket, $socket);
+            $ipcChannel = new StreamChannel($socket, $socket, $serializer);
 
             $socket = connect($uri, $key, $connectCancellation);
-            $resultChannel = new StreamChannel($socket, $socket);
+            $resultChannel = new StreamChannel($socket, $socket, $serializer);
         } catch (Throwable $exception) {
             trigger_error($exception->getMessage(), E_USER_ERROR);
         }
diff --git a/src/Psalm/Internal/Fork/IgbinarySerializer.php b/src/Psalm/Internal/Fork/IgbinarySerializer.php
new file mode 100644
index 00000000000..3c5744abf6d
--- /dev/null
+++ b/src/Psalm/Internal/Fork/IgbinarySerializer.php
@@ -0,0 +1,52 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Psalm\Internal\Fork;
+
+use Amp\Serialization\SerializationException;
+use Amp\Serialization\Serializer;
+use Throwable;
+
+use function igbinary_serialize;
+use function igbinary_unserialize;
+use function sprintf;
+
+/**
+ * @internal
+ */
+final class IgbinarySerializer implements Serializer
+{
+    public function serialize(mixed $data): string
+    {
+        try {
+            $data = igbinary_serialize($data);
+            if ($data === false) {
+                throw new SerializationException("Could not serialize data!");
+            }
+            return $data;
+        } catch (Throwable $exception) {
+            throw new SerializationException(
+                sprintf(
+                    'The given data could not be serialized: %s',
+                    $exception->getMessage(),
+                ),
+                0,
+                $exception,
+            );
+        }
+    }
+
+    public function unserialize(string $data): mixed
+    {
+        try {
+            return igbinary_unserialize($data);
+        } catch (Throwable $exception) {
+            throw new SerializationException(
+                'Exception thrown when unserializing data',
+                0,
+                $exception,
+            );
+        }
+    }
+}
diff --git a/src/Psalm/Internal/Fork/Pool.php b/src/Psalm/Internal/Fork/Pool.php
index 78252943624..d045645459c 100644
--- a/src/Psalm/Internal/Fork/Pool.php
+++ b/src/Psalm/Internal/Fork/Pool.php
@@ -18,7 +18,7 @@
 use AssertionError;
 use Closure;
 use Psalm\Progress\Progress;
-use Throwable;
+use Revolt\EventLoop;
 
 use function Amp\Future\await;
 use function array_map;
@@ -95,8 +95,11 @@ public function run(
             if ($task_done_closure) {
                 $f->map($task_done_closure);
             }
-            $f->catch(fn(Throwable $e) => throw $e);
-            $f->map(function () use (&$cnt, $total): void {
+            $id = EventLoop::delay(10.0, function () use ($file): void {
+                $this->progress->write(PHP_EOL."Processing $file is taking more than 10 seconds...".PHP_EOL);
+            });
+            $f->map(function () use (&$cnt, $total, $id): void {
+                EventLoop::cancel($id);
                 $cnt++;
                 if (!($cnt % 10)) {
                     $percent = (int) (($cnt*100) / $total);