Bug 1870008 - make high rate mode handling dynamic, r=farre

Differential Revision: https://phabricator.services.mozilla.com/D196591

dom/base/CCGCScheduler.cpp

@@ -637,9 +637,10 @@ void CCGCScheduler::EnsureGCRunner(TimeDuration aDelay) {
     return;
   }
 
-  TimeDuration minimumBudget = nsRefreshDriver::IsInHighRateMode()
-                                   ? TimeDuration::FromMilliseconds(1)
-                                   : mActiveIntersliceGCBudget;
+  TimeDuration minimumBudget = TimeDuration::FromMilliseconds(
+      std::max(nsRefreshDriver::HighRateMultiplier() *
+                   mActiveIntersliceGCBudget.ToMilliseconds(),
+               1.0));
 
   // Wait at most the interslice GC delay before forcing a run.
   mGCRunner = IdleTaskRunner::Create(
@@ -702,9 +703,8 @@ void CCGCScheduler::KillGCRunner() {
 void CCGCScheduler::EnsureCCRunner(TimeDuration aDelay, TimeDuration aBudget) {
   MOZ_ASSERT(!mDidShutdown);
 
-  TimeDuration minimumBudget = nsRefreshDriver::IsInHighRateMode()
-                                   ? TimeDuration::FromMilliseconds(1)
-                                   : aBudget;
+  TimeDuration minimumBudget = TimeDuration::FromMilliseconds(std::max(
+      nsRefreshDriver::HighRateMultiplier() * aBudget.ToMilliseconds(), 1.0));
 
   if (!mCCRunner) {
     mCCRunner = IdleTaskRunner::Create(

layout/base/nsRefreshDriver.cpp

@@ -143,6 +143,8 @@ namespace mozilla {
 
 static TimeStamp sMostRecentHighRateVsync;
 
+static TimeDuration sMostRecentHighRate;
+
 /*
  * The base class for all global refresh driver timers.  It takes care
  * of managing the list of refresh drivers attached to them and
@@ -233,12 +235,12 @@ class RefreshDriverTimer {
     TimeStamp mostRecentRefresh = MostRecentRefresh();
     TimeDuration refreshPeriod = GetTimerRate();
     TimeStamp idleEnd = mostRecentRefresh + refreshPeriod;
-    bool inHighRateMode = nsRefreshDriver::IsInHighRateMode();
+    double highRateMultiplier = nsRefreshDriver::HighRateMultiplier();
 
     // If we haven't painted for some time, then guess that we won't paint
     // again for a while, so the refresh driver is not a good way to predict
     // idle time.
-    if (!inHighRateMode &&
+    if (highRateMultiplier == 1.0 &&
         (idleEnd +
              refreshPeriod *
                  StaticPrefs::layout_idle_period_required_quiescent_frames() <
@@ -249,10 +251,9 @@ class RefreshDriverTimer {
     // End the predicted idle time a little early, the amount controlled by a
     // pref, to prevent overrunning the idle time and delaying a frame.
     // But do that only if we aren't in high rate mode.
-    idleEnd =
-        idleEnd -
-        TimeDuration::FromMilliseconds(
-            inHighRateMode ? 0 : StaticPrefs::layout_idle_period_time_limit());
+    idleEnd = idleEnd - TimeDuration::FromMilliseconds(
+                            highRateMultiplier *
+                            StaticPrefs::layout_idle_period_time_limit());
     return idleEnd < aDefault ? idleEnd : aDefault;
   }
 
@@ -837,9 +838,10 @@ class VsyncRefreshDriverTimer : public RefreshDriverTimer {
           ContentChild::GetPerformanceHintTarget(rate));
     }
 
-    if (TimeDuration::FromMilliseconds(nsRefreshDriver::DefaultInterval() / 2) >
+    if (TimeDuration::FromMilliseconds(nsRefreshDriver::DefaultInterval()) >
         rate) {
       sMostRecentHighRateVsync = tickStart;
+      sMostRecentHighRate = rate;
     }
 
     // On 32-bit Windows we sometimes get times where TimeStamp::Now() is not
@@ -1257,7 +1259,7 @@ int32_t nsRefreshDriver::DefaultInterval() {
 }
 
 /* static */
-bool nsRefreshDriver::IsInHighRateMode() {
+double nsRefreshDriver::HighRateMultiplier() {
   // We're in high rate mode if we've gotten a fast rate during the last
   // DefaultInterval().
   bool inHighRateMode =
@@ -1269,8 +1271,11 @@ bool nsRefreshDriver::IsInHighRateMode() {
   if (!inHighRateMode) {
     // Clear the timestamp so that the next call is faster.
     sMostRecentHighRateVsync = TimeStamp();
+    sMostRecentHighRate = TimeDuration();
+    return 1.0;
   }
-  return inHighRateMode;
+
+  return sMostRecentHighRate.ToMilliseconds() / DefaultInterval();
 }
 
 // Compute the interval to use for the refresh driver timer, in milliseconds.

layout/base/nsRefreshDriver.h

@@ -323,10 +323,12 @@ class nsRefreshDriver final : public mozilla::layers::TransactionIdAllocator,
   static int32_t DefaultInterval();
 
   /**
-   * Returns true if a recent vsync interval has been less than a half of
-   * DefaultInterval.
+   * Returns 1.0 if a recent rate wasn't smaller than
+   * DefaultInterval(). Otherwise return rate / DefaultInterval();
+   * So the return value is (0-1].
+   *
    */
-  static bool IsInHighRateMode();
+  static double HighRateMultiplier();
 
   bool IsInRefresh() { return mInRefresh; }
 

xpcom/threads/MainThreadIdlePeriod.cpp

@@ -48,11 +48,9 @@ MainThreadIdlePeriod::GetIdlePeriodHint(TimeStamp* aIdleDeadline) {
 
   // If the idle period is too small, then just return a null time
   // to indicate we are busy. Otherwise return the actual deadline.
-  //
-  // If we're in high frequency rate mode, idle.period.min isn't used but limit
-  // is 1.
+  double highRateMultiplier = nsRefreshDriver::HighRateMultiplier();
   TimeDuration minIdlePeriod = TimeDuration::FromMilliseconds(
-      nsRefreshDriver::IsInHighRateMode() ? 1 : StaticPrefs::idle_period_min());
+      std::max(highRateMultiplier * StaticPrefs::idle_period_min(), 1.0));
   bool busySoon = currentGuess.IsNull() ||
                   (now >= (currentGuess - minIdlePeriod)) ||
                   currentGuess < mLastIdleDeadline;
@@ -60,8 +58,9 @@ MainThreadIdlePeriod::GetIdlePeriodHint(TimeStamp* aIdleDeadline) {
   // During page load use higher minimum idle period.
   if (!busySoon && XRE_IsContentProcess() &&
       mozilla::dom::Document::HasRecentlyStartedForegroundLoads()) {
-    TimeDuration minIdlePeriod = TimeDuration::FromMilliseconds(
-        StaticPrefs::idle_period_during_page_load_min());
+    TimeDuration minIdlePeriod = TimeDuration::FromMilliseconds(std::max(
+        highRateMultiplier * StaticPrefs::idle_period_during_page_load_min(),
+        1.0));
     busySoon = (now >= (currentGuess - minIdlePeriod));
   }