7 files changed, 69 insertions, 7 deletions
diff --git a/libs/gui/Android.bp b/libs/gui/Android.bp
index ba3195a38e..f3d5aab089 100644
--- a/libs/gui/Android.bp
+++ b/libs/gui/Android.bp
@@ -166,6 +166,10 @@ cc_defaults {
         "bufferqueue/2.0/types.cpp",
     ],
 
+    whole_static_libs: [
+        "LibGuiProperties",
+    ],
+
     shared_libs: [
         "android.hardware.graphics.bufferqueue@1.0",
         "android.hardware.graphics.bufferqueue@2.0",
diff --git a/libs/gui/FrameTimestamps.cpp b/libs/gui/FrameTimestamps.cpp
index c04d9072bb..3215eca50f 100644
--- a/libs/gui/FrameTimestamps.cpp
+++ b/libs/gui/FrameTimestamps.cpp
@@ -18,6 +18,7 @@
 
 #define LOG_TAG "FrameEvents"
 
+#include <LibGuiProperties.sysprop.h>
 #include <android-base/stringprintf.h>
 #include <cutils/compiler.h>  // For CC_[UN]LIKELY
 #include <inttypes.h>
@@ -167,6 +168,11 @@ struct FrameNumberEqual {
 
 }  // namespace
 
+const size_t FrameEventHistory::MAX_FRAME_HISTORY =
+        sysprop::LibGuiProperties::frame_event_history_size().value_or(8);
+
+FrameEventHistory::FrameEventHistory() : mFrames(std::vector<FrameEvents>(MAX_FRAME_HISTORY)) {}
+
 FrameEventHistory::~FrameEventHistory() = default;
 
 FrameEvents* FrameEventHistory::getFrame(uint64_t frameNumber) {
@@ -348,6 +354,9 @@ std::shared_ptr<FenceTime> ProducerFrameEventHistory::createFenceTime(
 // ConsumerFrameEventHistory
 // ============================================================================
 
+ConsumerFrameEventHistory::ConsumerFrameEventHistory()
+      : mFramesDirty(std::vector<FrameEventDirtyFields>(MAX_FRAME_HISTORY)) {}
+
 ConsumerFrameEventHistory::~ConsumerFrameEventHistory() = default;
 
 void ConsumerFrameEventHistory::onDisconnect() {
@@ -443,9 +452,8 @@ void ConsumerFrameEventHistory::addRelease(uint64_t frameNumber,
     mFramesDirty[mReleaseOffset].setDirty<FrameEvent::RELEASE>();
 }
 
-void ConsumerFrameEventHistory::getFrameDelta(
-        FrameEventHistoryDelta* delta,
-        const std::array<FrameEvents, MAX_FRAME_HISTORY>::iterator& frame) {
+void ConsumerFrameEventHistory::getFrameDelta(FrameEventHistoryDelta* delta,
+                                              const std::vector<FrameEvents>::iterator& frame) {
     mProducerWantsEvents = true;
     size_t i = static_cast<size_t>(std::distance(mFrames.begin(), frame));
     if (mFramesDirty[i].anyDirty()) {
diff --git a/libs/gui/include/gui/FrameTimestamps.h b/libs/gui/include/gui/FrameTimestamps.h
index df02494bf4..4670edda99 100644
--- a/libs/gui/include/gui/FrameTimestamps.h
+++ b/libs/gui/include/gui/FrameTimestamps.h
@@ -106,6 +106,7 @@ struct CompositorTiming {
 // producer via deltas.
 class FrameEventHistory {
 public:
+    FrameEventHistory();
     virtual ~FrameEventHistory();
 
     FrameEvents* getFrame(uint64_t frameNumber);
@@ -113,10 +114,10 @@ public:
     void checkFencesForCompletion();
     void dump(std::string& outString) const;
 
-    static constexpr size_t MAX_FRAME_HISTORY = 8;
+    static const size_t MAX_FRAME_HISTORY;
 
 protected:
-    std::array<FrameEvents, MAX_FRAME_HISTORY> mFrames;
+    std::vector<FrameEvents> mFrames;
 
     CompositorTiming mCompositorTiming;
 };
@@ -204,6 +205,7 @@ private:
 // The consumer's interface to FrameEventHistory
 class ConsumerFrameEventHistory : public FrameEventHistory {
 public:
+    ConsumerFrameEventHistory();
     ~ConsumerFrameEventHistory() override;
 
     void onDisconnect();
@@ -224,9 +226,9 @@ public:
 
 private:
     void getFrameDelta(FrameEventHistoryDelta* delta,
-            const std::array<FrameEvents, MAX_FRAME_HISTORY>::iterator& frame);
+                       const std::vector<FrameEvents>::iterator& frame);
 
-    std::array<FrameEventDirtyFields, MAX_FRAME_HISTORY> mFramesDirty;
+    std::vector<FrameEventDirtyFields> mFramesDirty;
 
     size_t mQueueOffset{0};
     size_t mCompositionOffset{0};
diff --git a/libs/gui/sysprop/Android.bp b/libs/gui/sysprop/Android.bp
new file mode 100644
index 0000000000..e7f7c1fc86
--- /dev/null
+++ b/libs/gui/sysprop/Android.bp
@@ -0,0 +1,7 @@
+sysprop_library {
+    name: "LibGuiProperties",
+    srcs: ["*.sysprop"],
+    api_packages: ["android.sysprop"],
+    property_owner: "Platform",
+    vendor_available: true,
+}
diff --git a/libs/gui/sysprop/LibGuiProperties.sysprop b/libs/gui/sysprop/LibGuiProperties.sysprop
new file mode 100644
index 0000000000..0d54711095
--- /dev/null
+++ b/libs/gui/sysprop/LibGuiProperties.sysprop
@@ -0,0 +1,25 @@
+# Copyright (C) 2020 The Android Open Source Project
+#
+# Licensed under the Apache License, Version 2.0 (the License);
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an AS IS BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+module: "android.sysprop.LibGuiProperties"
+owner: Platform
+
+# Indicates how many elements should be present in the frame event histories.
+prop {
+    api_name: "frame_event_history_size"
+    type: Integer
+    scope: Public
+    access: Readonly
+    prop_name: "ro.lib_gui.frame_event_history_size"
+}
diff --git a/libs/gui/sysprop/api/LibGuiProperties-current.txt b/libs/gui/sysprop/api/LibGuiProperties-current.txt
new file mode 100644
index 0000000000..5b7f74e03e
--- /dev/null
+++ b/libs/gui/sysprop/api/LibGuiProperties-current.txt
@@ -0,0 +1,8 @@
+props {
+  module: "android.sysprop.LibGuiProperties"
+  prop {
+    api_name: "frame_event_history_size"
+    type: Integer
+    prop_name: "ro.lib_gui.frame_event_history_size"
+  }
+}
diff --git a/libs/gui/sysprop/api/LibGuiProperties-latest.txt b/libs/gui/sysprop/api/LibGuiProperties-latest.txt
new file mode 100644
index 0000000000..5b7f74e03e
--- /dev/null
+++ b/libs/gui/sysprop/api/LibGuiProperties-latest.txt
@@ -0,0 +1,8 @@
+props {
+  module: "android.sysprop.LibGuiProperties"
+  prop {
+    api_name: "frame_event_history_size"
+    type: Integer
+    prop_name: "ro.lib_gui.frame_event_history_size"
+  }
+}