Implement Display Layer Stats

Try to collect data for analyzing how many display controller layers we
need and what we use them for. Also part of a bug fixing for potential
memory leak of existing layer tracing work of winscope.

Test: adb shell dumpsys SurfaceFlinger --enable-layer-stats
Test: adb shell dumpsys SurfaceFlinger --disable-layer-stats
Test: adb shell dumpsys SurfaceFlinger --clear-layer-stats
Test: adb shell dumpsys SurfaceFlinger --dump-layer-stats
Bug: b/73668062
Change-Id: Ie08aa85d34db2c2c767b8e27eb5aad6f7c3fb975
Merged-In: Ie08aa85d34db2c2c767b8e27eb5aad6f7c3fb975
diff --git a/services/surfaceflinger/LayerStats.cpp b/services/surfaceflinger/LayerStats.cpp
new file mode 100644
index 0000000..dc99b41
--- /dev/null
+++ b/services/surfaceflinger/LayerStats.cpp
@@ -0,0 +1,181 @@
+/*
+ * Copyright 2018 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 "LayerStats"
+#define ATRACE_TAG ATRACE_TAG_GRAPHICS
+
+#include "LayerStats.h"
+#include "DisplayHardware/HWComposer.h"
+
+#include <android-base/stringprintf.h>
+#include <log/log.h>
+#include <utils/String8.h>
+#include <utils/Trace.h>
+
+namespace android {
+
+void LayerStats::enable() {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (mEnabled) return;
+    mLayerStatsMap.clear();
+    mEnabled = true;
+    ALOGD("Logging enabled");
+}
+
+void LayerStats::disable() {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> lock(mMutex);
+    if (!mEnabled) return;
+    mEnabled = false;
+    ALOGD("Logging disabled");
+}
+
+void LayerStats::clear() {
+    ATRACE_CALL();
+    std::lock_guard<std::mutex> lock(mMutex);
+    mLayerStatsMap.clear();
+    ALOGD("Cleared current layer stats");
+}
+
+bool LayerStats::isEnabled() {
+    return mEnabled;
+}
+
+void LayerStats::traverseLayerTreeStatsLocked(
+        std::vector<std::unique_ptr<LayerProtoParser::Layer>> layerTree,
+        const LayerProtoParser::LayerGlobal* layerGlobal) {
+    for (std::unique_ptr<LayerProtoParser::Layer>& layer : layerTree) {
+        if (!layer) continue;
+        traverseLayerTreeStatsLocked(std::move(layer->children), layerGlobal);
+        std::string key =
+                base::StringPrintf("%s,%s,%s,%s,%s,%s,%s,%s,%s",
+                                   destinationLocation(layer->hwcFrame.left,
+                                                       layerGlobal->resolution[0], true),
+                                   destinationLocation(layer->hwcFrame.top,
+                                                       layerGlobal->resolution[1], false),
+                                   destinationSize(layer->hwcFrame.right - layer->hwcFrame.left,
+                                                   layerGlobal->resolution[0], true),
+                                   destinationSize(layer->hwcFrame.bottom - layer->hwcFrame.top,
+                                                   layerGlobal->resolution[1], false),
+                                   layer->type.c_str(), scaleRatioWH(layer.get()).c_str(),
+                                   layerTransform(layer->hwcTransform), layer->pixelFormat.c_str(),
+                                   layer->dataspace.c_str());
+        mLayerStatsMap[key]++;
+    }
+}
+
+void LayerStats::logLayerStats(const LayersProto& layersProto) {
+    ATRACE_CALL();
+    auto layerGlobal = LayerProtoParser::generateLayerGlobalInfo(layersProto);
+    auto layerTree = LayerProtoParser::generateLayerTree(layersProto);
+    std::lock_guard<std::mutex> lock(mMutex);
+    traverseLayerTreeStatsLocked(std::move(layerTree), &layerGlobal);
+}
+
+void LayerStats::dump(String8& result) {
+    ATRACE_CALL();
+    ALOGD("Dumping");
+    result.append("Count,DstPosX,DstPosY,DstWidth,DstHeight,LayerType,WScale,HScale,");
+    result.append("Transform,PixelFormat,Dataspace\n");
+    std::lock_guard<std::mutex> lock(mMutex);
+    for (auto& u : mLayerStatsMap) {
+        result.appendFormat("%u,%s\n", u.second, u.first.c_str());
+    }
+}
+
+const char* LayerStats::destinationLocation(int32_t location, int32_t range, bool isHorizontal) {
+    static const char* locationArray[8] = {"0", "1/8", "1/4", "3/8", "1/2", "5/8", "3/4", "7/8"};
+    int32_t ratio = location * 8 / range;
+    if (ratio < 0) return "N/A";
+    if (isHorizontal) {
+        // X location is divided into 4 buckets {"0", "1/4", "1/2", "3/4"}
+        if (ratio > 6) return "3/4";
+        // use index 0, 2, 4, 6
+        return locationArray[ratio & ~1];
+    }
+    if (ratio > 7) return "7/8";
+    return locationArray[ratio];
+}
+
+const char* LayerStats::destinationSize(int32_t size, int32_t range, bool isWidth) {
+    static const char* sizeArray[8] = {"1/8", "1/4", "3/8", "1/2", "5/8", "3/4", "7/8", "1"};
+    int32_t ratio = size * 8 / range;
+    if (ratio < 0) return "N/A";
+    if (isWidth) {
+        // width is divided into 4 buckets {"1/4", "1/2", "3/4", "1"}
+        if (ratio > 6) return "1";
+        // use index 1, 3, 5, 7
+        return sizeArray[ratio | 1];
+    }
+    if (ratio > 7) return "1";
+    return sizeArray[ratio];
+}
+
+const char* LayerStats::layerTransform(int32_t transform) {
+    return getTransformName(static_cast<hwc_transform_t>(transform));
+}
+
+std::string LayerStats::scaleRatioWH(const LayerProtoParser::Layer* layer) {
+    if (!layer->type.compare("ColorLayer")) return "N/A,N/A";
+    std::string ret = "";
+    if (isRotated(layer->hwcTransform)) {
+        ret += scaleRatio(layer->hwcFrame.right - layer->hwcFrame.left,
+                          static_cast<int32_t>(layer->hwcCrop.bottom - layer->hwcCrop.top));
+        ret += ",";
+        ret += scaleRatio(layer->hwcFrame.bottom - layer->hwcFrame.top,
+                          static_cast<int32_t>(layer->hwcCrop.right - layer->hwcCrop.left));
+    } else {
+        ret += scaleRatio(layer->hwcFrame.right - layer->hwcFrame.left,
+                          static_cast<int32_t>(layer->hwcCrop.right - layer->hwcCrop.left));
+        ret += ",";
+        ret += scaleRatio(layer->hwcFrame.bottom - layer->hwcFrame.top,
+                          static_cast<int32_t>(layer->hwcCrop.bottom - layer->hwcCrop.top));
+    }
+    return ret;
+}
+
+const char* LayerStats::scaleRatio(int32_t destinationScale, int32_t sourceScale) {
+    // Make scale buckets from <1/64 to >= 16, to avoid floating point
+    // calculation, x64 on destinationScale first
+    int32_t scale = destinationScale * 64 / sourceScale;
+    if (!scale) return "<1/64";
+    if (scale < 2) return "1/64";
+    if (scale < 4) return "1/32";
+    if (scale < 8) return "1/16";
+    if (scale < 16) return "1/8";
+    if (scale < 32) return "1/4";
+    if (scale < 64) return "1/2";
+    if (scale < 128) return "1";
+    if (scale < 256) return "2";
+    if (scale < 512) return "4";
+    if (scale < 1024) return "8";
+    return ">=16";
+}
+
+bool LayerStats::isRotated(int32_t transform) {
+    return transform & HWC_TRANSFORM_ROT_90;
+}
+
+bool LayerStats::isVFlipped(int32_t transform) {
+    return transform & HWC_TRANSFORM_FLIP_V;
+}
+
+bool LayerStats::isHFlipped(int32_t transform) {
+    return transform & HWC_TRANSFORM_FLIP_H;
+}
+
+} // namespace android