Add statsd microbenchmark and fix a crash in LogEvent

+ We should benchmark the core functions in the critical path.
     1. LogEvent parsing
     2. Log matching
     3. Event processing in various metrics
     ....

+ Using microbenchmark, we can quantify the optimization we do in the future.

    ---------------------------------------------------------
    Benchmark                  Time           CPU Iterations
    ---------------------------------------------------------
    BM_LogEventCreation       4772 ns       4705 ns     145738

Test: make -j64 statsd_benchmark

Bug: 72242322

Change-Id: I43aa704ffdc7cd21e02ef9038eff66ca7022dbfb

cmds/statsd/Android.mk

@@ -221,6 +221,44 @@ LOCAL_STATIC_JAVA_LIBRARIES := \
 
 include $(BUILD_STATIC_JAVA_LIBRARY)
 
+##############################
+# statsd micro benchmark
+##############################
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := statsd_benchmark
+
+LOCAL_SRC_FILES := $(statsd_common_src) \
+                   benchmark/main.cpp \
+                   benchmark/hello_world_benchmark.cpp \
+                   benchmark/log_event_benchmark.cpp
+
+LOCAL_C_INCLUDES := $(statsd_common_c_includes)
+
+LOCAL_CFLAGS := -Wall \
+                -Werror \
+                -Wno-unused-parameter \
+                -Wno-unused-variable \
+                -Wno-unused-function \
+
+# Bug: http://b/29823425 Disable -Wvarargs for Clang update to r271374
+LOCAL_CFLAGS += -Wno-varargs
+
+LOCAL_AIDL_INCLUDES := $(statsd_common_aidl_includes)
+
+LOCAL_STATIC_LIBRARIES := \
+    $(statsd_common_static_libraries)
+
+LOCAL_SHARED_LIBRARIES := $(statsd_common_shared_libraries) \
+    libgtest_prod
+
+LOCAL_PROTOC_OPTIMIZE_TYPE := lite
+
+LOCAL_MODULE_TAGS := eng tests
+
+include $(BUILD_NATIVE_BENCHMARK)
+
+
 statsd_common_src:=
 statsd_common_aidl_includes:=
 statsd_common_c_includes:=
@@ -228,6 +266,4 @@ statsd_common_static_libraries:=
 statsd_common_shared_libraries:=
 
 
-##############################
-
 include $(call all-makefiles-under,$(LOCAL_PATH))

cmds/statsd/benchmark/hello_world_benchmark.cpp

@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 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.
+ */
+#include "benchmark/benchmark.h"
+
+static void BM_StringCreation(benchmark::State& state) {
+    while (state.KeepRunning()) std::string empty_string;
+}
+// Register the function as a benchmark
+BENCHMARK(BM_StringCreation);
+
+// Define another benchmark
+static void BM_StringCopy(benchmark::State& state) {
+    std::string x = "hello";
+    while (state.KeepRunning()) std::string copy(x);
+}
+BENCHMARK(BM_StringCopy);

cmds/statsd/benchmark/log_event_benchmark.cpp

@@ -0,0 +1,74 @@
+/*
+ * Copyright (C) 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.
+ */
+#include <vector>
+#include "benchmark/benchmark.h"
+#include "logd/LogEvent.h"
+
+namespace android {
+namespace os {
+namespace statsd {
+
+using std::vector;
+
+/* Special markers for android_log_list_element type */
+static const char EVENT_TYPE_LIST_STOP = '\n'; /* declare end of list  */
+static const char EVENT_TYPE_UNKNOWN = '?';    /* protocol error       */
+
+static const char EVENT_TYPE_INT = 0;
+static const char EVENT_TYPE_LONG = 1;
+static const char EVENT_TYPE_STRING = 2;
+static const char EVENT_TYPE_LIST = 3;
+static const char EVENT_TYPE_FLOAT = 4;
+
+static const int kLogMsgHeaderSize = 28;
+
+static void write4Bytes(int val, vector<char>* buffer) {
+    buffer->push_back(static_cast<char>(val));
+    buffer->push_back(static_cast<char>((val >> 8) & 0xFF));
+    buffer->push_back(static_cast<char>((val >> 16) & 0xFF));
+    buffer->push_back(static_cast<char>((val >> 24) & 0xFF));
+}
+
+static void getSimpleLogMsgData(log_msg* msg) {
+    vector<char> buffer;
+    // stats_log tag id
+    write4Bytes(1937006964, &buffer);
+    buffer.push_back(EVENT_TYPE_LIST);
+    buffer.push_back(2);  // field counts;
+    buffer.push_back(EVENT_TYPE_INT);
+    write4Bytes(10 /* atom id */, &buffer);
+    buffer.push_back(EVENT_TYPE_INT);
+    write4Bytes(99 /* a value to log*/, &buffer);
+    buffer.push_back(EVENT_TYPE_LIST_STOP);
+
+    msg->entry_v1.len = buffer.size();
+    msg->entry.hdr_size = kLogMsgHeaderSize;
+    msg->entry_v1.sec = time(nullptr);
+    std::copy(buffer.begin(), buffer.end(), msg->buf + kLogMsgHeaderSize);
+}
+
+static void BM_LogEventCreation(benchmark::State& state) {
+    log_msg msg;
+    getSimpleLogMsgData(&msg);
+    while (state.KeepRunning()) {
+        benchmark::DoNotOptimize(LogEvent(msg));
+    }
+}
+BENCHMARK(BM_LogEventCreation);
+
+}  //  namespace statsd
+}  //  namespace os
+}  //  namespace android

cmds/statsd/benchmark/main.cpp

@@ -0,0 +1,19 @@
+/*
+ * Copyright (C) 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.
+ */
+
+#include <benchmark/benchmark.h>
+
+BENCHMARK_MAIN();

cmds/statsd/src/logd/LogEvent.cpp

@@ -42,6 +42,7 @@ LogEvent::LogEvent(log_msg& msg) {
     mLogUid = msg.entry_v4.uid;
     init(mContext);
     if (mContext) {
+        // android_log_destroy will set mContext to NULL
         android_log_destroy(&mContext);
     }
 }
@@ -64,12 +65,17 @@ void LogEvent::init() {
         mContext = create_android_log_parser(buffer, len);
         init(mContext);
         // destroy the context to save memory.
-        android_log_destroy(&mContext);
+        if (mContext) {
+            // android_log_destroy will set mContext to NULL
+            android_log_destroy(&mContext);
+        }
     }
 }
 
 LogEvent::~LogEvent() {
     if (mContext) {
+        // This is for the case when LogEvent is created using the test interface
+        // but init() isn't called.
         android_log_destroy(&mContext);
     }
 }

cmds/statsd/src/logd/LogEvent.h

@@ -156,7 +156,7 @@ private:
     // This field is used when statsD wants to create log event object and write fields to it. After
     // calling init() function, this object would be destroyed to save memory usage.
     // When the log event is created from log msg, this field is never initiated.
-    android_log_context mContext;
+    android_log_context mContext = NULL;
 
     uint64_t mTimestampNs;