Add weighted telemetry probes for parallel restyles

components/style/gecko/data.rs

@@ -5,6 +5,7 @@
 //! Data needed to style a Gecko document.
 
 use atomic_refcell::{AtomicRef, AtomicRefCell, AtomicRefMut};
+use context::TraversalStatistics;
 use dom::TElement;
 use gecko_bindings::bindings::{self, RawServoStyleSet};
 use gecko_bindings::structs::{RawGeckoPresContextOwned, ServoStyleSetSizes, ServoStyleSheet};
@@ -108,15 +109,40 @@ impl StylesheetInDocument for GeckoStyleSheet {
     }
 }
 
+#[derive(Default)]
+/// Helper struct for counting traversals
+pub struct TraversalCount {
+    /// Total number of events
+    pub total_count: AtomicUsize,
+    /// Number of events which were parallel
+    pub parallel_count: AtomicUsize
+}
+
+impl TraversalCount {
+    fn record(&self, parallel: bool, count: u32) {
+        self.total_count.fetch_add(count as usize, Ordering::Relaxed);
+        if parallel {
+            self.parallel_count.fetch_add(count as usize, Ordering::Relaxed);
+        }
+    }
+
+    fn get(&self) -> (u32, u32) {
+        (self.total_count.load(Ordering::Relaxed) as u32,
+         self.parallel_count.load(Ordering::Relaxed) as u32)
+    }
+}
+
 /// The container for data that a Servo-backed Gecko document needs to style
 /// itself.
 pub struct PerDocumentStyleDataImpl {
     /// Rule processor.
     pub stylist: Stylist,
-    /// Total number of traversals that could have been parallel, for telemetry
-    pub total_traversal_count: AtomicUsize,
-    /// Number of parallel traversals
-    pub parallel_traversal_count: AtomicUsize,
+    /// Counter for traversals that could have been parallel, for telemetry
+    pub traversal_count: TraversalCount,
+    /// Counter for traversals, weighted by elements traversed,
+    pub traversal_count_traversed: TraversalCount,
+    /// Counter for traversals, weighted by elements styled,
+    pub traversal_count_styled: TraversalCount,
 }
 
 /// The data itself is an `AtomicRefCell`, which guarantees the proper semantics
@@ -138,8 +164,9 @@ impl PerDocumentStyleData {
 
         PerDocumentStyleData(AtomicRefCell::new(PerDocumentStyleDataImpl {
             stylist: Stylist::new(device, quirks_mode.into()),
-            total_traversal_count: Default::default(),
-            parallel_traversal_count: Default::default(),
+            traversal_count: Default::default(),
+            traversal_count_traversed: Default::default(),
+            traversal_count_styled: Default::default(),
         }))
     }
 
@@ -156,9 +183,16 @@ impl PerDocumentStyleData {
 
 impl Drop for PerDocumentStyleDataImpl {
     fn drop(&mut self) {
-        let total = self.total_traversal_count.load(Ordering::Relaxed) as u32;
-        let parallel = self.parallel_traversal_count.load(Ordering::Relaxed) as u32;
-        unsafe { bindings::Gecko_RecordTraversalStatistics(total, parallel) }
+        if !structs::GECKO_IS_NIGHTLY {
+            return
+        }
+        let (total, parallel)  = self.traversal_count.get();
+        let (total_t, parallel_t)  = self.traversal_count_traversed.get();
+        let (total_s, parallel_s)  = self.traversal_count_styled.get();
+
+        unsafe { bindings::Gecko_RecordTraversalStatistics(total, parallel,
+                                                           total_t, parallel_t,
+                                                           total_s, parallel_s) }
     }
 }
 
@@ -226,10 +260,11 @@ impl PerDocumentStyleDataImpl {
     }
 
     /// Record that a traversal happened for later collection as telemetry
-    pub fn record_traversal(&self, was_parallel: bool) {
-        self.total_traversal_count.fetch_add(1, Ordering::Relaxed);
-        if was_parallel {
-            self.parallel_traversal_count.fetch_add(1, Ordering::Relaxed);
+    pub fn record_traversal(&self, was_parallel: bool, stats: Option<TraversalStatistics>) {
+        self.traversal_count.record(was_parallel, 1);
+        if let Some(stats) = stats {
+            self.traversal_count_traversed.record(was_parallel, stats.elements_traversed);
+            self.traversal_count_styled.record(was_parallel, stats.elements_styled);
         }
     }
 }

components/style/gecko/generated/bindings.rs

@@ -499,6 +499,8 @@ extern "C" {
  pub fn Servo_SelectorList_Drop ( ptr : RawServoSelectorListOwned , ) ; 
 } extern "C" {
  pub fn Servo_SourceSizeList_Drop ( ptr : RawServoSourceSizeListOwned , ) ; 
+} extern "C" {
+ pub fn Gecko_RecordTraversalStatistics ( total : u32 , parallel : u32 , total_t : u32 , parallel_t : u32 , total_s : u32 , parallel_s : u32 , ) ; 
 } extern "C" {
  pub fn Gecko_IsInDocument ( node : RawGeckoNodeBorrowed , ) -> bool ; 
 } extern "C" {