Revert^2 Integrate layer tracing with perfetto
Define the perfetto custom data source LayerDataSource.
LayerDataSource is registered with perfetto. The data source
is used to listen to perfetto events (setup, start, stop, flush)
and to write trace packets to perfetto.
The user can configure/start/stop tracing via /system/bin/perfetto.
Tracing can operate in the following modes.
ACTIVE mode:
A layers snapshot is taken and written to perfetto for each vsyncid commit.
GENERATED mode:
Listens to the perfetto 'flush' event (e.g. when a bugreport is taken).
When a 'flush' event is received, the ring buffer of transactions (hold by TransactionTracing)
is processed by LayerTraceGenerator, a sequence of layers snapshots is generated
and written to perfetto.
DUMP mode:
When the 'start' event is received a single layers snapshot is taken
and written to perfetto.
Bug: b/284424784
Test: atest libsurfaceflinger_unittest && atest transactiontrace_testsuite
Change-Id: Ic1b10a040ec4533f0b56a4c8087c5a2898e3e34d
diff --git a/services/surfaceflinger/Tracing/LayerDataSource.h b/services/surfaceflinger/Tracing/LayerDataSource.h
new file mode 100644
index 0000000..7944092
--- /dev/null
+++ b/services/surfaceflinger/Tracing/LayerDataSource.h
@@ -0,0 +1,77 @@
+/*
+ * Copyright 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 "LayerTracing.h"
+
+#include <perfetto/tracing.h>
+
+#include <atomic>
+
+namespace android {
+
+/*
+ * Thread local storage used for fast (lock free) read of data source's properties.
+ *
+ */
+struct LayerDataSourceTlsState {
+ template <typename TraceContext>
+ explicit LayerDataSourceTlsState(const TraceContext& trace_context) {
+ auto dataSource = trace_context.GetDataSourceLocked();
+ mMode = dataSource.valid()
+ ? dataSource->GetMode()
+ : perfetto::protos::pbzero::SurfaceFlingerLayersConfig::Mode::MODE_GENERATED;
+ }
+
+ LayerTracing::Mode mMode;
+};
+
+struct LayerDataSourceTraits : public perfetto::DefaultDataSourceTraits {
+ using TlsStateType = LayerDataSourceTlsState;
+};
+
+/*
+ * Defines the Perfetto custom data source 'android.surfaceflinger.layers'.
+ *
+ * Registers the data source with Perfetto, listens to Perfetto events (setup/start/flush/stop)
+ * and writes trace packets to Perfetto.
+ *
+ */
+class LayerDataSource : public perfetto::DataSource<LayerDataSource, LayerDataSourceTraits> {
+public:
+ static void Initialize(LayerTracing&);
+ static void UnregisterLayerTracing();
+ void OnSetup(const SetupArgs&) override;
+ void OnStart(const StartArgs&) override;
+ void OnFlush(const FlushArgs&) override;
+ void OnStop(const StopArgs&) override;
+ LayerTracing::Mode GetMode() const;
+
+ static constexpr auto* kName = "android.surfaceflinger.layers";
+ static constexpr perfetto::BufferExhaustedPolicy kBufferExhaustedPolicy =
+ perfetto::BufferExhaustedPolicy::kStall;
+ static constexpr bool kRequiresCallbacksUnderLock = false;
+
+private:
+ static std::atomic<LayerTracing*> mLayerTracing;
+ LayerTracing::Mode mMode;
+ std::uint32_t mFlags;
+};
+
+} // namespace android
+
+PERFETTO_DECLARE_DATA_SOURCE_STATIC_MEMBERS(android::LayerDataSource);