Bug 1754562, make parent process' idle detection be aware of active RefreshDrivers in the other processes, r=mstange

Differential Revision: https://phabricator.services.mozilla.com/D138504

dom/base/ChromeUtils.cpp

@@ -1172,11 +1172,7 @@ already_AddRefed<Promise> ChromeUtils::RequestProcInfo(GlobalObject& aGlobal,
 
 /* static */
 bool ChromeUtils::VsyncEnabled(GlobalObject& aGlobal) {
-  mozilla::gfx::VsyncSource* vsyncSource =
-      gfxPlatform::GetPlatform()->GetHardwareVsync();
-  MOZ_ASSERT(vsyncSource != nullptr);
-
-  return vsyncSource->GetGlobalDisplay().IsVsyncEnabled();
+  return mozilla::gfx::VsyncSource::GetFastestVsyncRate().isSome();
 }
 
 /* static */

gfx/thebes/VsyncSource.cpp

@@ -8,6 +8,11 @@
 #include "nsXULAppAPI.h"
 #include "mozilla/VsyncDispatcher.h"
 #include "MainThreadUtils.h"
+#include "gfxPlatform.h"
+
+#ifdef MOZ_WAYLAND
+#  include "WaylandVsyncSource.h"
+#endif
 
 namespace mozilla {
 namespace gfx {
@@ -271,6 +276,33 @@ VsyncSource::Display::GetRefreshTimerVsyncDispatcher() {
   return mRefreshTimerVsyncDispatcher;
 }
 
+// static
+Maybe<TimeDuration> VsyncSource::GetFastestVsyncRate() {
+  Maybe<TimeDuration> retVal;
+  if (!gfxPlatform::Initialized()) {
+    return retVal;
+  }
+
+  mozilla::gfx::VsyncSource* vsyncSource =
+      gfxPlatform::GetPlatform()->GetHardwareVsync();
+  if (vsyncSource && vsyncSource->GetGlobalDisplay().IsVsyncEnabled()) {
+    retVal.emplace(vsyncSource->GetGlobalDisplay().GetVsyncRate());
+  }
+
+#ifdef MOZ_WAYLAND
+  Maybe<TimeDuration> waylandRate = WaylandVsyncSource::GetFastestVsyncRate();
+  if (waylandRate) {
+    if (!retVal) {
+      retVal.emplace(*waylandRate);
+    } else if (*waylandRate < *retVal) {
+      retVal = waylandRate;
+    }
+  }
+#endif
+
+  return retVal;
+}
+
 void VsyncSource::Shutdown() { GetGlobalDisplay().Shutdown(); }
 
 }  // namespace gfx

gfx/thebes/VsyncSource.h

@@ -8,6 +8,7 @@
 
 #include "nsTArray.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/Maybe.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/TimeStamp.h"
 #include "nsISupportsImpl.h"
@@ -125,6 +126,9 @@ class VsyncSource {
   virtual Display& GetGlobalDisplay() = 0;  // Works across all displays
   void Shutdown();
 
+  // Returns the rate of the fastest enabled VsyncSource::Display or Nothing().
+  static Maybe<TimeDuration> GetFastestVsyncRate();
+
  protected:
   virtual ~VsyncSource() = default;
 };

gfx/thebes/moz.build

@@ -260,6 +260,7 @@ LOCAL_INCLUDES += [
     "/dom/media/platforms/apple",
     "/dom/xml",
     "/gfx/cairo/cairo/src",
+    "/widget/gtk",
 ]
 
 if CONFIG["MOZ_WIDGET_TOOLKIT"] in ("android", "gtk"):

layout/base/nsRefreshDriver.cpp

@@ -2927,7 +2927,8 @@ void nsRefreshDriver::CancelPendingAnimationEvents(
 }
 
 /* static */
-TimeStamp nsRefreshDriver::GetIdleDeadlineHint(TimeStamp aDefault) {
+TimeStamp nsRefreshDriver::GetIdleDeadlineHint(TimeStamp aDefault,
+                                               IdleCheck aCheckType) {
   MOZ_ASSERT(NS_IsMainThread());
   MOZ_ASSERT(!aDefault.IsNull());
 
@@ -2938,7 +2939,10 @@ TimeStamp nsRefreshDriver::GetIdleDeadlineHint(TimeStamp aDefault) {
   // busy but tasks resulting from a tick on sThrottledRateTimer
   // counts as being idle.
   if (sRegularRateTimer) {
-    return sRegularRateTimer->GetIdleDeadlineHint(aDefault);
+    TimeStamp retVal = sRegularRateTimer->GetIdleDeadlineHint(aDefault);
+    if (retVal != aDefault) {
+      return retVal;
+    }
   }
 
   // The following calculation is only used on platform using per-BrowserChild
@@ -2950,6 +2954,8 @@ TimeStamp nsRefreshDriver::GetIdleDeadlineHint(TimeStamp aDefault) {
   // For now we use a somewhat simplistic approach that in many situations
   // gives us similar behaviour to what we would get using sRegularRateTimer:
   // use the highest result that is still lower than the aDefault fallback.
+  // XXXsmaug None of this makes much sense. We should always return the
+  // lowest result, not highest.
   TimeStamp hint = TimeStamp();
   if (sRegularRateTimerList) {
     for (RefreshDriverTimer* timer : *sRegularRateTimerList) {
@@ -2960,7 +2966,23 @@ TimeStamp nsRefreshDriver::GetIdleDeadlineHint(TimeStamp aDefault) {
     }
   }
 
-  return hint.IsNull() ? aDefault : hint;
+  if (!hint.IsNull()) {
+    return hint;
+  }
+
+  if (aCheckType == IdleCheck::AllVsyncListeners && XRE_IsParentProcess()) {
+    Maybe<TimeDuration> rate = mozilla::gfx::VsyncSource::GetFastestVsyncRate();
+    if (rate.isSome()) {
+      TimeStamp newHint = TimeStamp::Now() + *rate -
+                          TimeDuration::FromMilliseconds(
+                              StaticPrefs::layout_idle_period_time_limit());
+      if (newHint < aDefault) {
+        return newHint;
+      }
+    }
+  }
+
+  return aDefault;
 }
 
 /* static */

layout/base/nsRefreshDriver.h

@@ -359,8 +359,19 @@ class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
    *
    * If we're animating and we have skipped paints a time in the past
    * is returned.
+   *
+   * If aCheckType is AllVsyncListeners and we're in the parent process,
+   * which doesn't have a RefreshDriver ticking, but some other process does
+   * have, the return value is
+   * (now + refreshrate - layout.idle_period.time_limit) as an approximation
+   * when something will happen.
+   * This can be useful check when parent process tries to avoid having too
+   * long idle periods for example when it is sending input events to an
+   * active child process.
    */
-  static mozilla::TimeStamp GetIdleDeadlineHint(mozilla::TimeStamp aDefault);
+  enum IdleCheck { OnlyThisProcessRefreshDriver, AllVsyncListeners };
+  static mozilla::TimeStamp GetIdleDeadlineHint(mozilla::TimeStamp aDefault,
+                                                IdleCheck aCheckType);
 
   /**
    * It returns the expected timestamp of the next tick or nothing if the next

widget/gtk/WaylandVsyncSource.cpp

@@ -7,6 +7,7 @@
 #ifdef MOZ_WAYLAND
 
 #  include "WaylandVsyncSource.h"
+#  include "mozilla/UniquePtr.h"
 #  include "nsThreadUtils.h"
 #  include "nsISupportsImpl.h"
 #  include "MainThreadUtils.h"
@@ -50,6 +51,27 @@ static float GetFPS(TimeDuration aVsyncRate) {
   return 1000.0 / aVsyncRate.ToMilliseconds();
 }
 
+static UniquePtr<LinkedList<WaylandVsyncSource::WaylandDisplay>>
+    gWaylandDisplays;
+
+Maybe<TimeDuration> WaylandVsyncSource::GetFastestVsyncRate() {
+  Maybe<TimeDuration> retVal;
+  if (gWaylandDisplays) {
+    for (auto* display : *gWaylandDisplays) {
+      if (display->IsVsyncEnabled()) {
+        TimeDuration rate = display->GetVsyncRate();
+        if (!retVal.isSome()) {
+          retVal.emplace(rate);
+        } else if (rate < *retVal) {
+          retVal.ref() = rate;
+        }
+      }
+    }
+  }
+
+  return retVal;
+}
+
 WaylandVsyncSource::WaylandDisplay::WaylandDisplay()
     : mMutex("WaylandVsyncSource"),
       mIsShutdown(false),
@@ -60,6 +82,19 @@ WaylandVsyncSource::WaylandDisplay::WaylandDisplay()
       mVsyncRate(TimeDuration::FromMilliseconds(1000.0 / 60.0)),
       mLastVsyncTimeStamp(TimeStamp::Now()) {
   MOZ_ASSERT(NS_IsMainThread());
+
+  if (!gWaylandDisplays) {
+    gWaylandDisplays =
+        MakeUnique<LinkedList<WaylandVsyncSource::WaylandDisplay>>();
+  }
+  gWaylandDisplays->insertBack(this);
+}
+
+WaylandVsyncSource::WaylandDisplay::~WaylandDisplay() {
+  remove();  // Remove from the linked list.
+  if (gWaylandDisplays->isEmpty()) {
+    gWaylandDisplays = nullptr;
+  }
 }
 
 void WaylandVsyncSource::WaylandDisplay::MaybeUpdateSource(

widget/gtk/WaylandVsyncSource.h

@@ -8,6 +8,8 @@
 
 #include "base/thread.h"
 #include "mozilla/RefPtr.h"
+#include "mozilla/LinkedList.h"
+#include "mozilla/Maybe.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/Monitor.h"
 #include "mozilla/layers/NativeLayerWayland.h"
@@ -48,7 +50,10 @@ class WaylandVsyncSource final : public gfx::VsyncSource {
 
   virtual Display& GetGlobalDisplay() override { return *mGlobalDisplay; }
 
-  class WaylandDisplay final : public mozilla::gfx::VsyncSource::Display {
+  static Maybe<TimeDuration> GetFastestVsyncRate();
+
+  class WaylandDisplay final : public mozilla::gfx::VsyncSource::Display,
+                               public LinkedListElement<WaylandDisplay> {
    public:
     WaylandDisplay();
 
@@ -72,7 +77,7 @@ class WaylandVsyncSource final : public gfx::VsyncSource {
     virtual void Shutdown() override;
 
    private:
-    virtual ~WaylandDisplay() = default;
+    ~WaylandDisplay() override;
     void Refresh(const MutexAutoLock& aProofOfLock);
     void SetupFrameCallback(const MutexAutoLock& aProofOfLock);
     void CalculateVsyncRate(const MutexAutoLock& aProofOfLock,

xpcom/threads/IdleTaskRunner.cpp

@@ -188,7 +188,10 @@ void IdleTaskRunner::Schedule(bool aAllowIdleDispatch) {
   if (now >= mStartTime) {
     // Detect whether the refresh driver is ticking by checking if
     // GetIdleDeadlineHint returns its input parameter.
-    useRefreshDriver = (nsRefreshDriver::GetIdleDeadlineHint(now) != now);
+    useRefreshDriver =
+        (nsRefreshDriver::GetIdleDeadlineHint(
+             now, nsRefreshDriver::IdleCheck::OnlyThisProcessRefreshDriver) !=
+         now);
   } else {
     NS_WARNING_ASSERTION(!aAllowIdleDispatch,
                          "early callback, or time went backwards");

xpcom/threads/MainThreadIdlePeriod.cpp

@@ -38,7 +38,8 @@ MainThreadIdlePeriod::GetIdlePeriodHint(TimeStamp* aIdleDeadline) {
   TimeStamp currentGuess =
       now + TimeDuration::FromMilliseconds(kLongIdlePeriodMS);
 
-  currentGuess = nsRefreshDriver::GetIdleDeadlineHint(currentGuess);
+  currentGuess = nsRefreshDriver::GetIdleDeadlineHint(
+      currentGuess, nsRefreshDriver::IdleCheck::AllVsyncListeners);
   if (XRE_IsContentProcess()) {
     currentGuess = gfx::VRManagerChild::GetIdleDeadlineHint(currentGuess);
   }