diff --git a/docker/php/Dockerfile b/docker/php/Dockerfile
index a4a1a587..7dd40acc 100644
--- a/docker/php/Dockerfile
+++ b/docker/php/Dockerfile
@@ -47,10 +47,12 @@ RUN apk add --no-cache \
     && pecl install -o -f igbinary \
     && pecl install redis \
     && pecl install imagick \
+    && pecl install excimer \
     && docker-php-ext-enable \
         igbinary \
         redis \
         imagick \
+        excimer \
     && apk del \
         zlib-dev \
         libpng-dev \
diff --git a/inc/profile.php b/inc/profile.php
new file mode 100644
index 00000000..71b10ea0
--- /dev/null
+++ b/inc/profile.php
@@ -0,0 +1,21 @@
+<?php
+// From https://www.mediawiki.org/wiki/Excimer
+// Inject with `auto_prepend_file` in php.ini
+
+if (extension_loaded("excimer")) {
+	error_log("Profiler started", 0);
+
+	static $prof; // Keep object until the end of the request
+	$prof = new ExcimerProfiler();
+	$prof->setEventType(EXCIMER_REAL);
+	$prof->setPeriod(5); // every N seconds
+	$prof->setMaxDepth(250);
+
+	$prof->setFlushCallback(function ($log) {
+		error_log("Logged profile", 0);
+		file_put_contents('/tmp/profles-ramfs/excimer-traces.log', $log->formatCollapsed(), FILE_APPEND | LOCK_EX);
+	}, 1);
+	$prof->start();
+} else {
+	error_log("Profiler code injected, but no excimer extension installed");
+}