ui: add startup profiling (#36482)

* ui: add startup profiling

* lil more

system/ui/lib/application.py

@@ -6,6 +6,7 @@ import signal
 import sys
 import pyray as rl
 import threading
+from contextlib import contextmanager
 from collections.abc import Callable
 from collections import deque
 from dataclasses import dataclass
@@ -170,6 +171,7 @@ class GuiApplication:
     self._window_close_requested = True
 
   def init_window(self, title: str, fps: int = _DEFAULT_FPS):
+    with self._startup_profile_context():
       def _close(sig, frame):
         self.close()
         sys.exit(0)
@@ -202,6 +204,36 @@ class GuiApplication:
       if not PC:
         self._mouse.start()
 
+  @contextmanager
+  def _startup_profile_context(self):
+    if "PROFILE_STARTUP" not in os.environ:
+      yield
+      return
+
+    import cProfile
+    import io
+    import pstats
+
+    profiler = cProfile.Profile()
+    start_time = time.monotonic()
+    profiler.enable()
+
+    # do the init
+    yield
+
+    profiler.disable()
+    elapsed_ms = (time.monotonic() - start_time) * 1e3
+
+    stats_stream = io.StringIO()
+    pstats.Stats(profiler, stream=stats_stream).sort_stats("cumtime").print_stats(25)
+    print("\n=== Startup profile ===")
+    print(stats_stream.getvalue().rstrip())
+
+    green = "\033[92m"
+    reset = "\033[0m"
+    print(f"{green}UI window ready in {elapsed_ms:.1f} ms{reset}")
+    sys.exit(0)
+
   def set_modal_overlay(self, overlay, callback: Callable | None = None):
     if self._modal_overlay.overlay is not None:
       if self._modal_overlay.callback is not None: