diff --git a/services/surfaceflinger/Tracing/LayerTracing.cpp b/services/surfaceflinger/Tracing/LayerTracing.cpp
new file mode 100644
index 0000000..84890ee
--- /dev/null
+++ b/services/surfaceflinger/Tracing/LayerTracing.cpp
@@ -0,0 +1,130 @@
+/*
+ * 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.
+ */
+
+#undef LOG_TAG
+#define LOG_TAG "LayerTracing"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include <SurfaceFlinger.h>
+#include <android-base/stringprintf.h>
+#include <log/log.h>
+#include <utils/SystemClock.h>
+#include <utils/Trace.h>
+
+#include "LayerTracing.h"
+#include "RingBuffer.h"
+
+namespace android {
+
+LayerTracing::LayerTracing(SurfaceFlinger& flinger) : mFlinger(flinger) {
+    mBuffer = std::make_unique<RingBuffer<LayersTraceFileProto, LayersTraceProto>>();
+}
+
+LayerTracing::~LayerTracing() = default;
+
+bool LayerTracing::enable() {
+    std::scoped_lock lock(mTraceLock);
+    if (mEnabled) {
+        return false;
+    }
+    mBuffer->setSize(mBufferSizeInBytes);
+    mEnabled = true;
+    return true;
+}
+
+bool LayerTracing::disable() {
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return false;
+    }
+    mEnabled = false;
+    LayersTraceFileProto fileProto = createTraceFileProto();
+    mBuffer->writeToFile(fileProto, FILE_NAME);
+    return true;
+}
+
+bool LayerTracing::isEnabled() const {
+    std::scoped_lock lock(mTraceLock);
+    return mEnabled;
+}
+
+status_t LayerTracing::writeToFile() {
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return STATUS_OK;
+    }
+    LayersTraceFileProto fileProto = createTraceFileProto();
+    return mBuffer->writeToFile(fileProto, FILE_NAME);
+}
+
+void LayerTracing::setTraceFlags(uint32_t flags) {
+    std::scoped_lock lock(mTraceLock);
+    mFlags = flags;
+}
+
+void LayerTracing::setBufferSize(size_t bufferSizeInBytes) {
+    std::scoped_lock lock(mTraceLock);
+    mBufferSizeInBytes = bufferSizeInBytes;
+}
+
+bool LayerTracing::flagIsSet(uint32_t flags) const {
+    return (mFlags & flags) == flags;
+}
+
+LayersTraceFileProto LayerTracing::createTraceFileProto() const {
+    LayersTraceFileProto fileProto;
+    fileProto.set_magic_number(uint64_t(LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_H) << 32 |
+                               LayersTraceFileProto_MagicNumber_MAGIC_NUMBER_L);
+    return fileProto;
+}
+
+void LayerTracing::dump(std::string& result) const {
+    std::scoped_lock lock(mTraceLock);
+    base::StringAppendF(&result, "Tracing state: %s\n", mEnabled ? "enabled" : "disabled");
+    mBuffer->dump(result);
+}
+
+void LayerTracing::notify(const char* where) {
+    ATRACE_CALL();
+    std::scoped_lock lock(mTraceLock);
+    if (!mEnabled) {
+        return;
+    }
+
+    ATRACE_CALL();
+    LayersTraceProto entry;
+    entry.set_elapsed_realtime_nanos(elapsedRealtimeNano());
+    entry.set_where(where);
+    LayersProto layers(mFlinger.dumpDrawingStateProto(mFlags));
+
+    if (flagIsSet(LayerTracing::TRACE_EXTRA)) {
+        mFlinger.dumpOffscreenLayersProto(layers);
+    }
+    entry.mutable_layers()->Swap(&layers);
+
+    if (flagIsSet(LayerTracing::TRACE_HWC)) {
+        std::string hwcDump;
+        mFlinger.dumpHwc(hwcDump);
+        entry.set_hwc_blob(hwcDump);
+    }
+    if (!flagIsSet(LayerTracing::TRACE_COMPOSITION)) {
+        entry.set_excludes_composition_state(true);
+    }
+    mFlinger.dumpDisplayProto(entry);
+    mBuffer->emplace(std::move(entry));
+}
+
+} // namespace android
diff --git a/services/surfaceflinger/Tracing/LayerTracing.h b/services/surfaceflinger/Tracing/LayerTracing.h
new file mode 100644
index 0000000..8ca3587
--- /dev/null
+++ b/services/surfaceflinger/Tracing/LayerTracing.h
@@ -0,0 +1,77 @@
+/*
+ * 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 <android-base/thread_annotations.h>
+#include <layerproto/LayerProtoHeader.h>
+#include <utils/Errors.h>
+#include <utils/StrongPointer.h>
+#include <utils/Timers.h>
+
+#include <memory>
+#include <mutex>
+
+using namespace android::surfaceflinger;
+
+namespace android {
+
+template <typename FileProto, typename EntryProto>
+class RingBuffer;
+
+class SurfaceFlinger;
+
+/*
+ * LayerTracing records layer states during surface flinging. Manages tracing state and
+ * configuration.
+ */
+class LayerTracing {
+public:
+    LayerTracing(SurfaceFlinger& flinger);
+    ~LayerTracing();
+    bool enable();
+    bool disable();
+    bool isEnabled() const;
+    status_t writeToFile();
+    LayersTraceFileProto createTraceFileProto() const;
+    void notify(const char* where);
+
+    enum : uint32_t {
+        TRACE_INPUT = 1 << 1,
+        TRACE_COMPOSITION = 1 << 2,
+        TRACE_EXTRA = 1 << 3,
+        TRACE_HWC = 1 << 4,
+        TRACE_BUFFERS = 1 << 5,
+        TRACE_ALL = TRACE_INPUT | TRACE_COMPOSITION | TRACE_EXTRA,
+    };
+    void setTraceFlags(uint32_t flags);
+    bool flagIsSet(uint32_t flags) const;
+    void setBufferSize(size_t bufferSizeInBytes);
+    void dump(std::string&) const;
+
+private:
+    static constexpr auto FILE_NAME = "/data/misc/wmtrace/layers_trace.winscope";
+
+    SurfaceFlinger& mFlinger;
+    uint32_t mFlags = TRACE_INPUT;
+    mutable std::mutex mTraceLock;
+    bool mEnabled GUARDED_BY(mTraceLock) = false;
+    std::unique_ptr<RingBuffer<LayersTraceFileProto, LayersTraceProto>> mBuffer
+            GUARDED_BY(mTraceLock);
+    size_t mBufferSizeInBytes GUARDED_BY(mTraceLock) = 20 * 1024 * 1024;
+};
+
+} // namespace android
diff --git a/services/surfaceflinger/Tracing/RingBuffer.h b/services/surfaceflinger/Tracing/RingBuffer.h
new file mode 100644
index 0000000..d0fb3f2
--- /dev/null
+++ b/services/surfaceflinger/Tracing/RingBuffer.h
@@ -0,0 +1,112 @@
+/*
+ * 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 <android-base/file.h>
+#include <android-base/stringprintf.h>
+
+#include <log/log.h>
+#include <utils/Errors.h>
+#include <utils/SystemClock.h>
+#include <utils/Trace.h>
+#include <queue>
+
+namespace android {
+
+class SurfaceFlinger;
+
+template <typename FileProto, typename EntryProto>
+class RingBuffer {
+public:
+    size_t size() const { return mSizeInBytes; }
+    size_t used() const { return mUsedInBytes; }
+    size_t frameCount() const { return mStorage.size(); }
+    void setSize(size_t newSize) { mSizeInBytes = newSize; }
+    EntryProto& front() { return mStorage.front(); }
+    const EntryProto& front() const { return mStorage.front(); }
+
+    void reset(size_t newSize) {
+        // use the swap trick to make sure memory is released
+        std::queue<EntryProto>().swap(mStorage);
+        mSizeInBytes = newSize;
+        mUsedInBytes = 0U;
+    }
+    void flush(FileProto& fileProto) {
+        fileProto.mutable_entry()->Reserve(static_cast<int>(mStorage.size()));
+        while (!mStorage.empty()) {
+            auto entry = fileProto.add_entry();
+            entry->Swap(&mStorage.front());
+            mStorage.pop();
+        }
+    }
+
+    status_t writeToFile(FileProto& fileProto, std::string filename) {
+        ATRACE_CALL();
+        std::string output;
+        flush(fileProto);
+        reset(mSizeInBytes);
+        if (!fileProto.SerializeToString(&output)) {
+            ALOGE("Could not serialize proto.");
+            return UNKNOWN_ERROR;
+        }
+
+        // -rw-r--r--
+        const mode_t mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
+        if (!android::base::WriteStringToFile(output, filename, mode, getuid(), getgid(), true)) {
+            ALOGE("Could not save the proto file.");
+            return PERMISSION_DENIED;
+        }
+        return NO_ERROR;
+    }
+
+    std::vector<EntryProto> emplace(EntryProto&& proto) {
+        std::vector<EntryProto> replacedEntries;
+        size_t protoSize = static_cast<size_t>(proto.ByteSize());
+        while (mUsedInBytes + protoSize > mSizeInBytes) {
+            if (mStorage.empty()) {
+                return {};
+            }
+            mUsedInBytes -= static_cast<size_t>(mStorage.front().ByteSize());
+            replacedEntries.emplace_back(mStorage.front());
+            mStorage.pop();
+        }
+        mUsedInBytes += protoSize;
+        mStorage.emplace();
+        mStorage.back().Swap(&proto);
+        return replacedEntries;
+    }
+
+    void dump(std::string& result) const {
+        std::chrono::milliseconds duration(0);
+        if (frameCount() > 0) {
+            duration = std::chrono::duration_cast<std::chrono::milliseconds>(
+                    std::chrono::nanoseconds(systemTime() - front().elapsed_realtime_nanos()));
+        }
+        const int64_t durationCount = duration.count();
+        base::StringAppendF(&result,
+                            "  number of entries: %zu (%.2fMB / %.2fMB) duration: %" PRIi64 "ms\n",
+                            frameCount(), float(used()) / 1024.f * 1024.f,
+                            float(size()) / 1024.f * 1024.f, durationCount);
+    }
+
+private:
+    size_t mUsedInBytes = 0U;
+    size_t mSizeInBytes = 0U;
+    std::queue<EntryProto> mStorage;
+};
+
+} // namespace android