servo: Merge #11096 - Profile time spent saving the screenshot image (from mbrubeck:profile-image-saving); r=metajack

I did this to see if it was a significant factor in automated test runs.  (Spoiler: it isn't.)

Source-Repo: https://github.com/servo/servo
Source-Revision: 7b8bb0c2485eb46303d97918d91fce73bd98fea9

servo/components/compositing/compositor.rs

@@ -2166,19 +2166,21 @@ impl<Window: WindowMethods> IOCompositor<Window> {
                 })
             }
             CompositeTarget::PngFile => {
-                let img = self.draw_img(render_target_info,
-                                        width,
-                                        height);
-                match opts::get().output_file.as_ref() {
-                    Some(path) => match File::create(path) {
-                        Ok(mut file) => match DynamicImage::ImageRgb8(img).save(&mut file, ImageFormat::PNG) {
-                            Ok(()) => (),
-                            Err(e) => error!("Failed to save {} ({}).", path, e),
+                profile(ProfilerCategory::ImageSaving, None, self.time_profiler_chan.clone(), || {
+                    match opts::get().output_file.as_ref() {
+                        Some(path) => match File::create(path) {
+                            Ok(mut file) => {
+                                let img = self.draw_img(render_target_info, width, height);
+                                let dynamic_image = DynamicImage::ImageRgb8(img);
+                                if let Err(e) = dynamic_image.save(&mut file, ImageFormat::PNG) {
+                                    error!("Failed to save {} ({}).", path, e);
+                                }
+                            },
+                            Err(e) => error!("Failed to create {} ({}).", path, e),
                         },
-                        Err(e) => error!("Failed to create {} ({}).", path, e),
-                    },
-                    None => error!("No file specified."),
-                }
+                        None => error!("No file specified."),
+                    }
+                });
                 None
             }
         };

servo/components/profile/heartbeats.rs

@@ -37,6 +37,7 @@ pub fn init() {
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::PaintingPrepBuff);
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::Painting);
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::ImageDecoding);
+    maybe_create_heartbeat(&mut hbs, ProfilerCategory::ImageSaving);
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::ScriptAttachLayout);
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::ScriptConstellationMsg);
     maybe_create_heartbeat(&mut hbs, ProfilerCategory::ScriptDevtoolsMsg);

servo/components/profile/time.rs

@@ -97,6 +97,7 @@ impl Formattable for ProfilerCategory {
             ProfilerCategory::PaintingPrepBuff => "Buffer Prep",
             ProfilerCategory::Painting => "Painting",
             ProfilerCategory::ImageDecoding => "Image Decoding",
+            ProfilerCategory::ImageSaving => "Image Saving",
             ProfilerCategory::ScriptAttachLayout => "Script Attach Layout",
             ProfilerCategory::ScriptConstellationMsg => "Script Constellation Msg",
             ProfilerCategory::ScriptDevtoolsMsg => "Script Devtools Msg",

servo/components/profile_traits/time.rs

@@ -57,6 +57,7 @@ pub enum ProfilerCategory {
     PaintingPrepBuff,
     Painting,
     ImageDecoding,
+    ImageSaving,
     ScriptAttachLayout,
     ScriptConstellationMsg,
     ScriptDevtoolsMsg,

servo/tests/heartbeats/characterize.py

@@ -37,6 +37,7 @@ HEARTBEAT_PROFILER_CATEGORIES = [
     ("PaintingPrepBuff", HEARTBEAT_DEFAULT_WINDOW_SIZE),
     ("Painting", HEARTBEAT_DEFAULT_WINDOW_SIZE),
     ("ImageDecoding", HEARTBEAT_DEFAULT_WINDOW_SIZE),
+    ("ImageSaving", HEARTBEAT_DEFAULT_WINDOW_SIZE),
     ("ScriptAttachLayout", HEARTBEAT_DEFAULT_WINDOW_SIZE),
     ("ScriptConstellationMsg", HEARTBEAT_DEFAULT_WINDOW_SIZE),
     ("ScriptDevtoolsMsg", HEARTBEAT_DEFAULT_WINDOW_SIZE),