1 files changed, 12 insertions, 1 deletions
diff --git a/src/servo/platform/osmain.rs b/src/servo/platform/osmain.rs
index daee2460906..6ea213e1542 100644
--- a/src/servo/platform/osmain.rs
+++ b/src/servo/platform/osmain.rs
@@ -13,6 +13,7 @@ import dom::event::{Event, ResizeEvent};
 import layers::ImageLayer;
 import geom::size::Size2D;
 import std::cmp::fuzzy_eq;
+import std::time::precise_time_ns;
 import vec::push;
 
 type OSMain = chan<Msg>;
@@ -34,6 +35,13 @@ fn OSMain() -> OSMain {
     }
 }
 
+fn time(msg: str, callback: fn()) {
+    let start_time = precise_time_ns();
+    callback();
+    let end_time = precise_time_ns();
+    #debug("%s took %u ms", msg, ((end_time - start_time) / 1000000u64) as uint);
+}
+
 fn mainloop(po: port<Msg>) {
     let key_handlers: @dvec<chan<()>> = @dvec();
     let event_listeners: @dvec<chan<Event>> = @dvec();
@@ -108,7 +116,10 @@ fn mainloop(po: port<Msg>) {
 
         #debug("osmain: drawing to screen");
 
-        layers::rendergl::render_scene(context, *scene);
+        do time("compositing") {
+            layers::rendergl::render_scene(context, *scene);
+        }
+
         glut::swap_buffers();
         glut::post_redisplay();
     }