Add rate limiting to fps reporter.
From a user perspective, the jittery frame rate is jarring, and from a
performance perspective submitting a binder call every frame is
overkill. To address those two concerns add rate-limiting from
SurfaceFlinger to limit the frame rate reporting.
As part of this patch, extract OneShotTimer's fake clock interface to a
SF-common location so that FpsReporter can share that interface for
testing.
Bug: 186265654
Test: Manually inspect fps overlay
Test: libsurfaceflinger_unittest
Change-Id: I45eb994d847abbb9fc8d5ff7d07ad51a1a790176
diff --git a/services/surfaceflinger/Clock.h b/services/surfaceflinger/Clock.h
new file mode 100644
index 0000000..3f23c6d
--- /dev/null
+++ b/services/surfaceflinger/Clock.h
@@ -0,0 +1,42 @@
+/*
+ * Copyright 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.
+ */
+
+#pragma once
+
+#include <chrono>
+
+namespace android {
+
+// Abstract interface for timekeeping which can be injected for unit tests.
+class Clock {
+public:
+ Clock() = default;
+ virtual ~Clock() = default;
+
+ // Returns the current time
+ virtual std::chrono::steady_clock::time_point now() const = 0;
+};
+
+class SteadyClock : public Clock {
+public:
+ virtual ~SteadyClock() = default;
+
+ std::chrono::steady_clock::time_point now() const override {
+ return std::chrono::steady_clock::now();
+ }
+};
+
+} // namespace android
\ No newline at end of file