Add LatencyTracker to InputDispatcher
LatencyTracker will be used to record the complete timeline of an input
event dispatch, from the kernel to the presentation of a graphics frame
to the display.
The data about input event timeline is coming from three different
locations:
1) notifyMotion: this is when the InputDispatcher first learns about the
event from InputReader. At this point, we learn the time when the event
was first created, to time when the event was read by the user space,
and we are now adding the timestamps when the InputReader notifies the
dispatcher about the event.
2) finishInputEvent: this is when the app sends an 'ack' that a specific
input event has been processed. Through this call, we learn about when
the event was first sent to the app, and when it was read by the app. At
this time, we are also collecting the 'finishTime', so that we can
measure the total time that the app spent processing the event.
3) sendTimeline: this is when the SurfaceFlinger notifies the app about
the metrics for a specific frame. This metrics information is passed
down through the InputChannel to the InputDispatcher. Here we learn
about the time when the app sent the buffer to the SurfaceFlinger
(gpuCompletedTime), and the time when the frame was presented
(presentTime).
Overall, the end-to-end touch latency is presentTime - eventTime.
The rest of the data can be used to measure the breakdown of this
latency.
The goal of LatencyTracker is to combine all this data and present a
complete, unified timeline for a specific input event for further data analysis.
In a separate CL, we will report this complete timeline to statsd.
Bug: 169866723
Test: atest inputflinger_tests
Change-Id: I6e6e80e3393878fe86f3935c7c0e13dfff8629f9
diff --git a/services/inputflinger/dispatcher/InputEventTimeline.h b/services/inputflinger/dispatcher/InputEventTimeline.h
new file mode 100644
index 0000000..77b8472
--- /dev/null
+++ b/services/inputflinger/dispatcher/InputEventTimeline.h
@@ -0,0 +1,108 @@
+/*
+ * Copyright (C) 2021 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.
+ */
+
+#ifndef _UI_INPUT_INPUTDISPATCHER_INPUTEVENTTIMELINE_H
+#define _UI_INPUT_INPUTDISPATCHER_INPUTEVENTTIMELINE_H
+
+#include <binder/IBinder.h>
+#include <input/Input.h>
+#include <unordered_map>
+
+namespace android {
+
+namespace inputdispatcher {
+
+/**
+ * Describes the input event timeline for each connection.
+ * An event with the same inputEventId can go to more than 1 connection simultaneously.
+ * For each connection that the input event goes to, there will be a separate ConnectionTimeline
+ * created.
+ * To create a complete ConnectionTimeline, we must receive two calls:
+ * 1) setDispatchTimeline
+ * 2) setGraphicsTimeline
+ *
+ * In a typical scenario, the dispatch timeline is known first. Later, if a frame is produced, the
+ * graphics timeline is available.
+ */
+struct ConnectionTimeline {
+ // DispatchTimeline
+ nsecs_t deliveryTime; // time at which the event was sent to the receiver
+ nsecs_t consumeTime; // time at which the receiver read the event
+ nsecs_t finishTime; // time at which the finish event was received
+ // GraphicsTimeline
+ std::array<nsecs_t, GraphicsTimeline::SIZE> graphicsTimeline;
+
+ ConnectionTimeline(nsecs_t deliveryTime, nsecs_t consumeTime, nsecs_t finishTime);
+ ConnectionTimeline(std::array<nsecs_t, GraphicsTimeline::SIZE> graphicsTimeline);
+
+ /**
+ * True if all contained timestamps are valid, false otherwise.
+ */
+ bool isComplete() const;
+ /**
+ * Set the dispatching-related times. Return true if the operation succeeded, false if the
+ * dispatching times have already been set. If this function returns false, it likely indicates
+ * an error from the app side.
+ */
+ bool setDispatchTimeline(nsecs_t deliveryTime, nsecs_t consumeTime, nsecs_t finishTime);
+ /**
+ * Set the graphics-related times. Return true if the operation succeeded, false if the
+ * graphics times have already been set. If this function returns false, it likely indicates
+ * an error from the app side.
+ */
+ bool setGraphicsTimeline(std::array<nsecs_t, GraphicsTimeline::SIZE> graphicsTimeline);
+
+ inline bool operator==(const ConnectionTimeline& rhs) const;
+ inline bool operator!=(const ConnectionTimeline& rhs) const;
+
+private:
+ bool mHasDispatchTimeline = false;
+ bool mHasGraphicsTimeline = false;
+};
+
+struct InputEventTimeline {
+ InputEventTimeline(bool isDown, nsecs_t eventTime, nsecs_t readTime);
+ const bool isDown; // True if this is an ACTION_DOWN event
+ const nsecs_t eventTime;
+ const nsecs_t readTime;
+
+ struct IBinderHash {
+ std::size_t operator()(const sp<IBinder>& b) const {
+ return std::hash<IBinder*>{}(b.get());
+ }
+ };
+
+ std::unordered_map<sp<IBinder>, ConnectionTimeline, IBinderHash> connectionTimelines;
+
+ bool operator==(const InputEventTimeline& rhs) const;
+};
+
+class InputEventTimelineProcessor {
+protected:
+ InputEventTimelineProcessor() {}
+ virtual ~InputEventTimelineProcessor() {}
+
+public:
+ /**
+ * Process the provided timeline
+ */
+ virtual void processTimeline(const InputEventTimeline& timeline) = 0;
+};
+
+} // namespace inputdispatcher
+} // namespace android
+
+#endif // _UI_INPUT_INPUTDISPATCHER_INPUTEVENTTIMELINE_H