drm_hwcomposer: Make flattening thread-based instead of vsync-based
Using vsync means consume some CPU time every frame for
IRQ -> Kernel_Thread -> UserSpace_listener thread transitions.
Framework tries to reduce vsync usage to the minimum, by using timelines
instead.
New flattening controller thread wakes-up only once per second.
This commit also removes flattening info from dumpsys. Practice shows
that it is almost useless. Instead debugging can be done using ALOGV
dumps.
Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/compositor/FlatteningController.h b/compositor/FlatteningController.h
new file mode 100644
index 0000000..2be6ce4
--- /dev/null
+++ b/compositor/FlatteningController.h
@@ -0,0 +1,71 @@
+/*
+ * Copyright (C) 2023 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>
+#include <condition_variable>
+#include <functional>
+#include <thread>
+
+namespace android {
+
+// NOLINTNEXTLINE(misc-unused-using-decls): False positive
+using std::chrono_literals::operator""s;
+
+struct FlatConCallbacks {
+ std::function<void()> trigger;
+};
+
+class FlatteningController {
+ public:
+ static auto CreateInstance(FlatConCallbacks &cbks)
+ -> std::shared_ptr<FlatteningController>;
+
+ void Disable() {
+ auto lock = std::lock_guard<std::mutex>(mutex_);
+ flatten_next_frame_ = false;
+ disabled_ = true;
+ }
+
+ /* Compositor should call this every frame */
+ bool NewFrame();
+
+ auto ShouldFlatten() const {
+ return flatten_next_frame_;
+ }
+
+ void StopThread() {
+ auto lock = std::lock_guard<std::mutex>(mutex_);
+ cbks_ = {};
+ cv_.notify_all();
+ }
+
+ static constexpr auto kTimeout = 1s;
+
+ private:
+ FlatteningController() = default;
+ static void ThreadFn(const std::shared_ptr<FlatteningController> &fc);
+
+ bool flatten_next_frame_{};
+ bool disabled_{};
+ decltype(std::chrono::system_clock::now()) sleep_until_{};
+ std::mutex mutex_;
+ std::condition_variable cv_;
+ FlatConCallbacks cbks_;
+};
+
+} // namespace android