SF: Optimize layer history in scheduler
Register layers with LayerHistory by storing a weak pointer rather than
allocating a LayerHandle. Query layer visibility when needed instead of
synchronizing it to LayerInfo whenever Layer::isVisible is called. Store
active/inactive layers in contiguous memory instead of two hash maps for
cache efficiency, and minimal allocation and run time of operations like
clearing history. Remove redundant ref-counting, locking, and frequency-
period conversion in LayerInfo. Avoid sleeping in unit tests.
This is also prework for per-display layer history.
Bug: 130554049
Bug: 134772048
Test: go/wm-smoke with debug.sf.layer_history_trace
Test: C2/F2 test cases from spreadsheet
Test: LayerHistoryTest with new test cases
Change-Id: Ibfcfe46cd76ebd93b916d4a0c737a19e837d4ff1
diff --git a/services/surfaceflinger/Scheduler/LayerHistory.h b/services/surfaceflinger/Scheduler/LayerHistory.h
index 5598cc1..15ac8ca 100644
--- a/services/surfaceflinger/Scheduler/LayerHistory.h
+++ b/services/surfaceflinger/Scheduler/LayerHistory.h
@@ -16,76 +16,78 @@
#pragma once
-#include <array>
-#include <cinttypes>
-#include <cstdint>
-#include <numeric>
-#include <string>
-#include <unordered_map>
-
+#include <android-base/thread_annotations.h>
+#include <utils/RefBase.h>
#include <utils/Timers.h>
-#include "LayerInfo.h"
-#include "SchedulerUtils.h"
+#include <memory>
+#include <mutex>
+#include <utility>
+#include <vector>
namespace android {
+
+class Layer;
+
namespace scheduler {
-/*
- * This class represents information about layers that are considered current. We keep an
- * unordered map between layer name and LayerInfo.
- */
+class LayerInfo;
+
+// Records per-layer history of scheduling-related information (primarily present time),
+// heuristically categorizes layers as active or inactive, and summarizes stats about
+// active layers (primarily maximum refresh rate). See go/content-fps-detection-in-scheduler.
class LayerHistory {
public:
- // Handle for each layer we keep track of.
- class LayerHandle {
- public:
- LayerHandle(LayerHistory& lh, int64_t id) : mId(id), mLayerHistory(lh) {}
- ~LayerHandle() { mLayerHistory.destroyLayer(mId); }
-
- const int64_t mId;
-
- private:
- LayerHistory& mLayerHistory;
- };
-
LayerHistory();
~LayerHistory();
- // When the layer is first created, register it.
- std::unique_ptr<LayerHandle> createLayer(const std::string name, float minRefreshRate,
- float maxRefreshRate);
+ // Layers are unregistered when the weak reference expires.
+ void registerLayer(Layer*, float lowRefreshRate, float highRefreshRate);
- // Method for inserting layers and their requested present time into the unordered map.
- void insert(const std::unique_ptr<LayerHandle>& layerHandle, nsecs_t presentTime, bool isHdr);
- // Method for setting layer visibility
- void setVisibility(const std::unique_ptr<LayerHandle>& layerHandle, bool visible);
+ // Marks the layer as active, and records the given state to its history.
+ void record(Layer*, nsecs_t presentTime, bool isHDR, nsecs_t now);
- // Returns the desired refresh rate, which is a max refresh rate of all the current
- // layers. See go/content-fps-detection-in-scheduler for more information.
- std::pair<float, bool> getDesiredRefreshRateAndHDR();
+ struct Summary {
+ float maxRefreshRate; // Maximum refresh rate among recently active layers.
+ bool isHDR; // True if any recently active layer has HDR content.
+ };
- // Clears all layer history.
- void clearHistory();
+ // Rebuilds sets of active/inactive layers, and accumulates stats for active layers.
+ Summary summarize(nsecs_t now);
- // Removes the handle and the object from the map.
- void destroyLayer(const int64_t id);
+ void clear();
private:
- // Removes the layers that have been idle for a given amount of time from mLayerInfos.
- void removeIrrelevantLayers() REQUIRES(mLock);
+ friend class LayerHistoryTest;
- // Information about currently active layers.
- std::mutex mLock;
- std::unordered_map<int64_t, std::shared_ptr<LayerInfo>> mActiveLayerInfos GUARDED_BY(mLock);
- std::unordered_map<int64_t, std::shared_ptr<LayerInfo>> mInactiveLayerInfos GUARDED_BY(mLock);
+ using LayerPair = std::pair<wp<Layer>, std::unique_ptr<LayerInfo>>;
+ using LayerInfos = std::vector<LayerPair>;
- // Each layer has it's own ID. This variable keeps track of the count.
- static std::atomic<int64_t> sNextId;
+ struct ActiveLayers {
+ LayerInfos& infos;
+ const size_t index;
- // Flag whether to log layer FPS in systrace
- bool mTraceEnabled = false;
+ auto begin() { return infos.begin(); }
+ auto end() { return begin() + index; }
+ };
+
+ ActiveLayers activeLayers() REQUIRES(mLock) { return {mLayerInfos, mActiveLayersEnd}; }
+
+ // Iterates over layers in a single pass, swapping pairs such that active layers precede
+ // inactive layers, and inactive layers precede expired layers. Removes expired layers by
+ // truncating after inactive layers.
+ void partitionLayers(nsecs_t now) REQUIRES(mLock);
+
+ mutable std::mutex mLock;
+
+ // Partitioned such that active layers precede inactive layers. For fast lookup, the few active
+ // layers are at the front, and weak pointers are stored in contiguous memory to hit the cache.
+ LayerInfos mLayerInfos GUARDED_BY(mLock);
+ size_t mActiveLayersEnd GUARDED_BY(mLock) = 0;
+
+ // Whether to emit systrace output and debug logs.
+ const bool mTraceEnabled;
};
} // namespace scheduler
-} // namespace android
\ No newline at end of file
+} // namespace android