Backed out changeset 00726df4997c (bug 1190074) for bustage on a CLOSED TREE

js/src/jsapi.cpp

@@ -368,12 +368,12 @@ IterPerformanceStats(JSContext* cx,
             continue;
         }
         js::AutoCompartment autoCompartment(cx, compartment);
-        mozilla::RefPtr<PerformanceGroup> ownGroup = compartment->performanceMonitoring.getOwnGroup();
+        PerformanceGroup* ownGroup = compartment->performanceMonitoring.getOwnGroup(cx);
         if (ownGroup->data.ticks == 0) {
             // Don't report compartments that have never been used.
             continue;
         }
-        mozilla::RefPtr<PerformanceGroup> sharedGroup = compartment->performanceMonitoring.getSharedGroup(cx);
+        PerformanceGroup* sharedGroup = compartment->performanceMonitoring.getSharedGroup(cx);
         if (!(*walker)(cx,
                        ownGroup->data, ownGroup->uid, &sharedGroup->uid,
                        closure)) {
@@ -383,7 +383,7 @@ IterPerformanceStats(JSContext* cx,
     }
 
     // Finally, report the process stats
-    *processStats = rt->stopwatch.performance.getOwnGroup()->data;
+    *processStats = rt->stopwatch.performance;
     return true;
 }
 

js/src/jsapi.h

@@ -13,7 +13,6 @@
 #include "mozilla/MemoryReporting.h"
 #include "mozilla/Range.h"
 #include "mozilla/RangedPtr.h"
-#include "mozilla/RefPtr.h"
 
 #include <stdarg.h>
 #include <stddef.h>
@@ -5515,22 +5514,15 @@ struct PerformanceGroup {
         stopwatch_ = nullptr;
     }
 
-    // Refcounting. For use with mozilla::RefPtr.
+    explicit PerformanceGroup(JSContext* cx, void* key);
-    void AddRef();
+    ~PerformanceGroup()
-    void Release();
+    {
-
+        MOZ_ASSERT(refCount_ == 0);
-    // Construct a PerformanceGroup for a single compartment.
+    }
-    explicit PerformanceGroup(JSRuntime* rt);
+  private:
-
-    // Construct a PerformanceGroup for a group of compartments.
-    explicit PerformanceGroup(JSContext* rt, void* key);
-
-private:
     PerformanceGroup& operator=(const PerformanceGroup&) = delete;
     PerformanceGroup(const PerformanceGroup&) = delete;
 
-    JSRuntime* runtime_;
-
     // The stopwatch currently monitoring the group,
     // or `nullptr` if none. Used ony for comparison.
     const AutoStopwatch* stopwatch_;
@@ -5542,14 +5534,20 @@ private:
     // The hash key for this PerformanceGroup.
     void* const key_;
 
-    // A reference counter.
+    // Increment/decrement the refcounter, return the updated value.
+    uint64_t incRefCount() {
+        MOZ_ASSERT(refCount_ + 1 > 0);
+        return ++refCount_;
+    }
+    uint64_t decRefCount() {
+        MOZ_ASSERT(refCount_ > 0);
+        return --refCount_;
+    }
+    friend struct PerformanceGroupHolder;
+
+private:
+    // A reference counter. Maintained by PerformanceGroupHolder.
     uint64_t refCount_;
-
-
-    // `true` if this PerformanceGroup may be shared by several
-    // compartments, `false` if it is dedicated to a single
-    // compartment.
-    const bool isSharedGroup_;
 };
 
 //
@@ -5566,7 +5564,7 @@ struct PerformanceGroupHolder {
     js::PerformanceGroup* getSharedGroup(JSContext*);
 
     // Get the own group.
-    js::PerformanceGroup* getOwnGroup();
+    js::PerformanceGroup* getOwnGroup(JSContext*);
 
     // `true` if the this holder is currently associated to a shared
     // PerformanceGroup, `false` otherwise. Use this method to avoid
@@ -5586,6 +5584,8 @@ struct PerformanceGroupHolder {
 
     explicit PerformanceGroupHolder(JSRuntime* runtime)
       : runtime_(runtime)
+      , sharedGroup_(nullptr)
+      , ownGroup_(nullptr)
     {   }
     ~PerformanceGroupHolder();
 
@@ -5600,8 +5600,8 @@ struct PerformanceGroupHolder {
     // The PerformanceGroups held by this object.
     // Initially set to `nullptr` until the first call to `getGroup`.
     // May be reset to `nullptr` by a call to `unlink`.
-    mozilla::RefPtr<js::PerformanceGroup> sharedGroup_;
+    js::PerformanceGroup* sharedGroup_;
-    mozilla::RefPtr<js::PerformanceGroup> ownGroup_;
+    js::PerformanceGroup* ownGroup_;
 };
 
 /**

js/src/vm/Interpreter.cpp

@@ -389,6 +389,22 @@ class AutoStopwatch final
     // loop.  Used only for comparison.
     uint64_t iteration_;
 
+    // `true` if this object is currently used to monitor performance
+    // for a shared PerformanceGroup, `false` otherwise, i.e. if the
+    // stopwatch mechanism is off or if another stopwatch is already
+    // in charge of monitoring for the same PerformanceGroup.
+    bool isMonitoringForGroup_;
+
+    // `true` if this object is currently used to monitor performance
+    // for a single compartment, `false` otherwise, i.e. if the
+    // stopwatch mechanism is off or if another stopwatch is already
+    // in charge of monitoring for the same PerformanceGroup.
+    bool isMonitoringForSelf_;
+
+    // `true` if this stopwatch is the topmost stopwatch on the stack
+    // for this event, `false` otherwise.
+    bool isMonitoringForTop_;
+
     // `true` if we are monitoring jank, `false` otherwise.
     bool isMonitoringJank_;
     // `true` if we are monitoring CPOW, `false` otherwise.
@@ -399,20 +415,6 @@ class AutoStopwatch final
     uint64_t systemTimeStart_;
     uint64_t CPOWTimeStart_;
 
-   // The performance group shared by this compartment and possibly
-   // others, or `nullptr` if another AutoStopwatch is already in
-   // charge of monitoring that group.
-   mozilla::RefPtr<js::PerformanceGroup> sharedGroup_;
-
-   // The toplevel group, representing the entire process, or `nullptr`
-   // if another AutoStopwatch is already in charge of monitoring that group.
-   mozilla::RefPtr<js::PerformanceGroup> topGroup_;
-
-   // The performance group specific to this compartment, or
-   // `nullptr` if another AutoStopwatch is already in charge of
-   // monitoring that group.
-   mozilla::RefPtr<js::PerformanceGroup> ownGroup_;
-
    public:
     // If the stopwatch is active, constructing an instance of
     // AutoStopwatch causes it to become the current owner of the
@@ -422,6 +424,9 @@ class AutoStopwatch final
     explicit inline AutoStopwatch(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM)
       : cx_(cx)
       , iteration_(0)
+      , isMonitoringForGroup_(false)
+      , isMonitoringForSelf_(false)
+      , isMonitoringForTop_(false)
       , isMonitoringJank_(false)
       , isMonitoringCPOW_(false)
       , userTimeStart_(0)
@@ -437,23 +442,52 @@ class AutoStopwatch final
         JSRuntime* runtime = cx_->runtime();
         iteration_ = runtime->stopwatch.iteration;
 
-        sharedGroup_ = acquireGroup(compartment->performanceMonitoring.getSharedGroup(cx));
+        PerformanceGroup* sharedGroup = compartment->performanceMonitoring.getSharedGroup(cx);
-        if (sharedGroup_)
+        if (!sharedGroup) {
-            topGroup_ = acquireGroup(runtime->stopwatch.performance.getOwnGroup());
+            // Either this Runtime is not configured for Performance Monitoring, or we couldn't
+            // allocate the group, or there was a problem with the hashtable.
+            return;
+        }
 
-        if (runtime->stopwatch.isMonitoringPerCompartment())
+        if (!sharedGroup->hasStopwatch(iteration_)) {
-            ownGroup_ = acquireGroup(compartment->performanceMonitoring.getOwnGroup());
+            // We are now in charge of monitoring this group for the tick,
+            // until destruction of `this` or until we enter a nested event
+            // loop and `iteration_` is incremented.
+            sharedGroup->acquireStopwatch(iteration_, this);
+            isMonitoringForGroup_ = true;
+        }
 
-        if (!sharedGroup_ && !ownGroup_) {
+        PerformanceGroup* ownGroup = nullptr;
+        if (runtime->stopwatch.isMonitoringPerCompartment()) {
+            // As above, but for the group representing just this compartment.
+            ownGroup = compartment->performanceMonitoring.getOwnGroup(cx);
+            if (!ownGroup->hasStopwatch(iteration_)) {
+                ownGroup->acquireStopwatch(iteration_, this);
+                isMonitoringForSelf_ = true;
+            }
+        }
+
+        if (runtime->stopwatch.isEmpty) {
+            // This is the topmost stopwatch on the stack.
+            // It will be in charge of updating the per-process
+            // performance data.
+            runtime->stopwatch.isEmpty = false;
+            isMonitoringForTop_ = true;
+
+            MOZ_ASSERT(isMonitoringForGroup_);
+        }
+
+        if (!isMonitoringForGroup_ && !isMonitoringForSelf_) {
             // We are not in charge of monitoring anything.
+            // (isMonitoringForTop_ implies isMonitoringForGroup_,
+            // so we do not need to check it)
             return;
         }
 
         enter();
     }
-    ~AutoStopwatch()
+    ~AutoStopwatch() {
-    {
+        if (!isMonitoringForGroup_ && !isMonitoringForSelf_) {
-        if (!sharedGroup_ && !ownGroup_) {
             // We are not in charge of monitoring anything.
             // (isMonitoringForTop_ implies isMonitoringForGroup_,
             // so we do not need to check it)
@@ -471,19 +505,31 @@ class AutoStopwatch final
             return;
         }
 
-        releaseGroup(sharedGroup_);
-        releaseGroup(topGroup_);
-        releaseGroup(ownGroup_);
-
         // Finish and commit measures
         exit();
+
+        // Now release groups.
+        if (isMonitoringForGroup_) {
+            PerformanceGroup* sharedGroup = compartment->performanceMonitoring.getSharedGroup(cx_);
+            MOZ_ASSERT(sharedGroup);
+            sharedGroup->releaseStopwatch(iteration_, this);
+        }
+
+        if (isMonitoringForSelf_) {
+            PerformanceGroup* ownGroup = compartment->performanceMonitoring.getOwnGroup(cx_);
+            MOZ_ASSERT(ownGroup);
+            ownGroup->releaseStopwatch(iteration_, this);
+        }
+
+        if (isMonitoringForTop_)
+            runtime->stopwatch.isEmpty = true;
     }
    private:
     void enter() {
         JSRuntime* runtime = cx_->runtime();
 
         if (runtime->stopwatch.isMonitoringCPOW()) {
-            CPOWTimeStart_ = runtime->stopwatch.performance.getOwnGroup()->data.totalCPOWTime;
+            CPOWTimeStart_ = runtime->stopwatch.performance.totalCPOWTime;
             isMonitoringCPOW_ = true;
         }
 
@@ -517,54 +563,46 @@ class AutoStopwatch final
         uint64_t CPOWTimeDelta = 0;
         if (isMonitoringCPOW_ && runtime->stopwatch.isMonitoringCPOW()) {
             // We were monitoring CPOW when we entered and we still are.
-            CPOWTimeDelta = runtime->stopwatch.performance.getOwnGroup()->data.totalCPOWTime - CPOWTimeStart_;
+            CPOWTimeDelta = runtime->stopwatch.performance.totalCPOWTime - CPOWTimeStart_;
 
         }
         commitDeltasToGroups(userTimeDelta, systemTimeDelta, CPOWTimeDelta);
     }
 
-    // Attempt to acquire a group
+    void commitDeltasToGroups(uint64_t userTimeDelta,
-    // If the group is `null` or if the group already has a stopwatch,
+                              uint64_t systemTimeDelta,
-    // do nothing and return `null`.
+                              uint64_t CPOWTimeDelta)
-    // Otherwise, bind the group to `this` for the current iteration
+    {
-    // and return `group`.
+        JSCompartment* compartment = cx_->compartment();
-    PerformanceGroup* acquireGroup(PerformanceGroup* group) {
-        if (!group)
-            return nullptr;
 
-        if (group->hasStopwatch(iteration_))
+        PerformanceGroup* sharedGroup = compartment->performanceMonitoring.getSharedGroup(cx_);
-            return nullptr;
+        MOZ_ASSERT(sharedGroup);
+        applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, sharedGroup->data);
 
-        group->acquireStopwatch(iteration_, this);
+        if (isMonitoringForSelf_) {
-        return group;
+            PerformanceGroup* ownGroup = compartment->performanceMonitoring.getOwnGroup(cx_);
+            MOZ_ASSERT(ownGroup);
+            applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, ownGroup->data);
+        }
+
+        if (isMonitoringForTop_) {
+            JSRuntime* runtime = cx_->runtime();
+            applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, runtime->stopwatch.performance);
+        }
     }
 
-    // Release a group.
-    // Noop if `group` is null or if `this` is not the stopwatch
-    // of `group` for the current iteration.
-    void releaseGroup(PerformanceGroup* group) {
-        if (group)
-            group->releaseStopwatch(iteration_, this);
-    }
 
-    void commitDeltasToGroups(uint64_t userTimeDelta, uint64_t systemTimeDelta,
+    void applyDeltas(uint64_t userTimeDelta,
-                              uint64_t CPOWTimeDelta) const {
+                     uint64_t systemTimeDelta,
-        applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, sharedGroup_);
+                     uint64_t CPOWTimeDelta,
-        applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, topGroup_);
+                     PerformanceData& data) const {
-        applyDeltas(userTimeDelta, systemTimeDelta, CPOWTimeDelta, ownGroup_);
-    }
 
-    void applyDeltas(uint64_t userTimeDelta, uint64_t systemTimeDelta,
+        data.ticks++;
-                     uint64_t CPOWTimeDelta, PerformanceGroup* group) const {
-        if (!group)
-            return;
-
-        group->data.ticks++;
 
         uint64_t totalTimeDelta = userTimeDelta + systemTimeDelta;
-        group->data.totalUserTime += userTimeDelta;
+        data.totalUserTime += userTimeDelta;
-        group->data.totalSystemTime += systemTimeDelta;
+        data.totalSystemTime += systemTimeDelta;
-        group->data.totalCPOWTime += CPOWTimeDelta;
+        data.totalCPOWTime += CPOWTimeDelta;
 
         // Update an array containing the number of times we have missed
         // at least 2^0 successive ms, 2^1 successive ms, ...
@@ -574,10 +612,10 @@ class AutoStopwatch final
         size_t i = 0;
         uint64_t duration = 1000;
         for (i = 0, duration = 1000;
-             i < ArrayLength(group->data.durations) && duration < totalTimeDelta;
+             i < ArrayLength(data.durations) && duration < totalTimeDelta;
              ++i, duration *= 2)
         {
-            group->data.durations[i]++;
+            data.durations[i]++;
         }
     }
 

js/src/vm/Runtime.cpp

@@ -222,8 +222,7 @@ JSRuntime::JSRuntime(JSRuntime* parentRuntime)
     largeAllocationFailureCallback(nullptr),
     oomCallback(nullptr),
     debuggerMallocSizeOf(ReturnZeroSize),
-    lastAnimationTime(0),
+    lastAnimationTime(0)
-    stopwatch(thisFromCtor())
 {
     setGCStoreBufferPtr(&gc.storeBuffer);
 
@@ -931,17 +930,40 @@ js::PerformanceGroupHolder::getHashKey(JSContext* cx)
 void
 js::PerformanceGroupHolder::unlink()
 {
-    ownGroup_ = nullptr;
+    if (ownGroup_) {
+        js_delete(ownGroup_);
+        ownGroup_ = nullptr;
+    }
+
+    if (!sharedGroup_) {
+        // The group has never been instantiated.
+        return;
+    }
+
+    js::PerformanceGroup* group = sharedGroup_;
     sharedGroup_ = nullptr;
+
+    if (group->decRefCount() > 0) {
+        // The group has at least another owner.
+        return;
+    }
+
+
+    JSRuntime::Stopwatch::Groups::Ptr ptr =
+        runtime_->stopwatch.groups().lookup(group->key_);
+    MOZ_ASSERT(ptr);
+    runtime_->stopwatch.groups().remove(ptr);
+    js_delete(group);
 }
 
 PerformanceGroup*
-js::PerformanceGroupHolder::getOwnGroup()
+js::PerformanceGroupHolder::getOwnGroup(JSContext* cx)
 {
     if (ownGroup_)
         return ownGroup_;
 
-    return ownGroup_ = runtime_->new_<PerformanceGroup>(runtime_);
+    ownGroup_ = runtime_->new_<PerformanceGroup>(cx, nullptr);
+    return ownGroup_;
 }
 
 PerformanceGroup*
@@ -963,58 +985,31 @@ js::PerformanceGroupHolder::getSharedGroup(JSContext* cx)
         if (!sharedGroup_)
             return nullptr;
 
-        runtime_->stopwatch.groups().add(ptr, key, sharedGroup_);
+        if (!runtime_->stopwatch.groups().add(ptr, key, sharedGroup_)) {
+            js_delete(sharedGroup_);
+            sharedGroup_ = nullptr;
+            return nullptr;
+        }
     }
 
+    sharedGroup_->incRefCount();
+
     return sharedGroup_;
 }
 
 PerformanceData*
 js::GetPerformanceData(JSRuntime* rt)
 {
-    return &rt->stopwatch.performance.getOwnGroup()->data;
+    return &rt->stopwatch.performance;
 }
 
-js::PerformanceGroup::PerformanceGroup(JSRuntime* rt)
+js::PerformanceGroup::PerformanceGroup(JSContext* cx, void* key)
-  : uid(rt->stopwatch.uniqueId()),
+  : uid(cx->runtime()->stopwatch.uniqueId())
-    runtime_(rt),
+  , stopwatch_(nullptr)
-    stopwatch_(nullptr),
+  , iteration_(0)
-    iteration_(0),
+  , key_(key)
-    key_(nullptr),
+  , refCount_(0)
-    refCount_(0),
-    isSharedGroup_(false)
-{ }
-
- js::PerformanceGroup::PerformanceGroup(JSContext* cx, void* key)
-   : uid(cx->runtime()->stopwatch.uniqueId()),
-     runtime_(cx->runtime()),
-     stopwatch_(nullptr),
-     iteration_(0),
-     key_(key),
-     refCount_(0),
-     isSharedGroup_(true)
-{ }
-
-void
-js::PerformanceGroup::AddRef()
 {
-    ++refCount_;
-}
-
-void
-js::PerformanceGroup::Release()
-{
-    MOZ_ASSERT(refCount_ > 0);
-    --refCount_;
-    if (refCount_ > 0)
-        return;
-    if (!isSharedGroup_)
-        return;
-
-    JSRuntime::Stopwatch::Groups::Ptr ptr = runtime_->stopwatch.groups().lookup(key_);
-    MOZ_ASSERT(ptr);
-    runtime_->stopwatch.groups().remove(ptr);
-    js_delete(this);
 }
 
 void

js/src/vm/Runtime.h

@@ -1512,11 +1512,6 @@ struct JSRuntime : public JS::shadow::Runtime,
             return groups_;
         }
 
-        /**
-         * Performance data on the entire runtime.
-         */
-        js::PerformanceGroupHolder performance;
-
         /**
          * The number of times we have entered the event loop.
          * Used to reset counters whenever we enter the loop,
@@ -1528,6 +1523,17 @@ struct JSRuntime : public JS::shadow::Runtime,
          */
         uint64_t iteration;
 
+        /**
+         * `true` if no stopwatch has been registered for the
+         * current run of the event loop, `false` until then.
+         */
+        bool isEmpty;
+
+        /**
+         * Performance data on the entire runtime.
+         */
+        js::PerformanceData performance;
+
         /**
          * Callback used to ask the embedding to determine in which
          * Performance Group the current execution belongs. Typically, this is
@@ -1540,9 +1546,9 @@ struct JSRuntime : public JS::shadow::Runtime,
          */
         JSCurrentPerfGroupCallback currentPerfGroupCallback;
 
-        Stopwatch(JSRuntime* runtime)
+        Stopwatch()
-          : performance(runtime)
+          : iteration(0)
-          , iteration(0)
+          , isEmpty(true)
           , currentPerfGroupCallback(nullptr)
           , isMonitoringJank_(false)
           , isMonitoringCPOW_(false)
@@ -1559,6 +1565,7 @@ struct JSRuntime : public JS::shadow::Runtime,
          */
         void reset() {
             ++iteration;
+            isEmpty = true;
         }
         /**
          * Activate/deactivate stopwatch measurement of jank.