Add sysprop for tuning caching inactive layer

A system property, debug.sf.layer_caching_active_layer_timeout_ms, is added for user to specify milliseconds timeout to tune inactive layer heuristic.

Bug: 190228095
Test: adb root; adb shell setprop debug.sf.layer_caching_active_layer_timeout_ms 100; adb shell stop; adb shell start
Change-Id: I2607f0817af15f3a8ddcaa237b2a336c7edd315e

2 files changed, 12 insertions, 2 deletions

diff --git a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
index ca1d69d579..c76078d39a 100644
--- a/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
+++ b/services/surfaceflinger/CompositionEngine/include/compositionengine/impl/planner/Flattener.h
@@ -37,7 +37,7 @@ class Predictor;
 
 class Flattener {
 public:
-    Flattener(bool enableHolePunch = false) : mEnableHolePunch(enableHolePunch) {}
+    Flattener(bool enableHolePunch = false);
 
     void setDisplaySize(ui::Size size) { mDisplaySize = size; }
 
@@ -162,6 +162,7 @@ private:
     size_t mCachedSetCreationCount = 0;
     size_t mCachedSetCreationCost = 0;
     std::unordered_map<size_t, size_t> mInvalidatedCachedSetAges;
+    std::chrono::nanoseconds mActiveLayerTimeout = kActiveLayerTimeout;
 
     static constexpr auto kActiveLayerTimeout = std::chrono::nanoseconds(150ms);
 };
diff --git a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
index 233b5f2131..48fb51f7ac 100644
--- a/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/planner/Flattener.cpp
@@ -19,6 +19,7 @@
 // #define LOG_NDEBUG 0
 #define ATRACE_TAG ATRACE_TAG_GRAPHICS
 
+#include <android-base/properties.h>
 #include <compositionengine/impl/planner/Flattener.h>
 #include <compositionengine/impl/planner/LayerState.h>
 
@@ -59,6 +60,14 @@ bool isSameStack(const std::vector<const LayerState*>& incomingLayers,
 
 } // namespace
 
+Flattener::Flattener(bool enableHolePunch) : mEnableHolePunch(enableHolePunch) {
+    const int timeoutInMs =
+            base::GetIntProperty(std::string("debug.sf.layer_caching_active_layer_timeout_ms"), 0);
+    if (timeoutInMs != 0) {
+        mActiveLayerTimeout = std::chrono::milliseconds(timeoutInMs);
+    }
+}
+
 NonBufferHash Flattener::flattenLayers(const std::vector<const LayerState*>& layers,
                                        NonBufferHash hash, time_point now) {
     ATRACE_CALL();
@@ -370,7 +379,7 @@ std::vector<Flattener::Run> Flattener::findCandidateRuns(time_point now) const {
     bool runHasFirstLayer = false;
 
     for (auto currentSet = mLayers.cbegin(); currentSet != mLayers.cend(); ++currentSet) {
-        const bool layerIsInactive = now - currentSet->getLastUpdate() > kActiveLayerTimeout;
+        const bool layerIsInactive = now - currentSet->getLastUpdate() > mActiveLayerTimeout;
         const bool layerHasBlur = currentSet->hasBlurBehind();
         if (layerIsInactive && (firstLayer || runHasFirstLayer || !layerHasBlur) &&
             !currentSet->hasHdrLayers() && !currentSet->hasProtectedLayers()) {