liblog: Add liblog test suite

(cherry picked from commit 8d1fdb50)

Change-Id: Ia457d518b4e7ff37e840336ff0c48583709700d4

include/log/log.h

 /*
- * Copyright (C) 2005-2013 The Android Open Source Project
+ * Copyright (C) 2005-2014 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.
@@ -563,4 +563,4 @@ int __android_log_buf_print(int bufID, int prio, const char *tag, const char *fm
 }
 #endif
 
-#endif // _LIBS_CUTILS_LOG_H
+#endif /* _LIBS_LOG_LOG_H */

include/log/log_read.h

+/*
+ * Copyright (C) 2013-2014 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.
+ */
+
+#ifndef _LIBS_LOG_LOG_READ_H
+#define _LIBS_LOG_LOG_READ_H
+
+#include <time.h>
+
+#define NS_PER_SEC 1000000000ULL
+#ifdef __cplusplus
+struct log_time : public timespec {
+public:
+    log_time(timespec &T)
+    {
+        tv_sec = T.tv_sec;
+        tv_nsec = T.tv_nsec;
+    }
+    log_time(void)
+    {
+    }
+    log_time(clockid_t id)
+    {
+        clock_gettime(id, (timespec *) this);
+    }
+    log_time(const char *T)
+    {
+        const uint8_t *c = (const uint8_t *) T;
+        tv_sec = c[0] | (c[1] << 8) | (c[2] << 16) | (c[3] << 24);
+        tv_nsec = c[4] | (c[5] << 8) | (c[6] << 16) | (c[7] << 24);
+    }
+    bool operator== (const timespec &T) const
+    {
+        return (tv_sec == T.tv_sec) && (tv_nsec == T.tv_nsec);
+    }
+    bool operator!= (const timespec &T) const
+    {
+        return !(*this == T);
+    }
+    bool operator< (const timespec &T) const
+    {
+        return (tv_sec < T.tv_sec)
+            || ((tv_sec == T.tv_sec) && (tv_nsec < T.tv_nsec));
+    }
+    bool operator>= (const timespec &T) const
+    {
+        return !(*this < T);
+    }
+    bool operator> (const timespec &T) const
+    {
+        return (tv_sec > T.tv_sec)
+            || ((tv_sec == T.tv_sec) && (tv_nsec > T.tv_nsec));
+    }
+    bool operator<= (const timespec &T) const
+    {
+        return !(*this > T);
+    }
+    uint64_t nsec(void) const
+    {
+        return static_cast<uint64_t>(tv_sec) * NS_PER_SEC + tv_nsec;
+    }
+};
+#else
+typedef struct timespec log_time;
+#endif
+
+#endif /* define _LIBS_LOG_LOG_READ_H */

liblog/Android.mk

 #
-# Copyright (C) 2008 The Android Open Source Project
+# Copyright (C) 2008-2014 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.
@@ -67,7 +67,6 @@ LOCAL_LDLIBS := -lpthread
 LOCAL_CFLAGS := -DFAKE_LOG_DEVICE=1 -m64
 include $(BUILD_HOST_STATIC_LIBRARY)
 
-
 # Shared and static library for target
 # ========================================================
 include $(CLEAR_VARS)
@@ -79,3 +78,5 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := liblog
 LOCAL_WHOLE_STATIC_LIBRARIES := liblog
 include $(BUILD_SHARED_LIBRARY)
+
+include $(call first-makefiles-under,$(LOCAL_PATH))

liblog/tests/Android.mk

+#
+# Copyright (C) 2013-2014 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.
+#
+
+LOCAL_PATH := $(call my-dir)
+
+# -----------------------------------------------------------------------------
+# Benchmarks.
+# -----------------------------------------------------------------------------
+
+test_module_prefix := liblog-
+test_tags := tests
+
+benchmark_c_flags := \
+    -Ibionic/tests \
+    -Wall -Wextra \
+    -Werror \
+    -fno-builtin \
+    -std=gnu++11
+
+benchmark_src_files := \
+    benchmark_main.cpp \
+    liblog_benchmark.cpp \
+
+# Build benchmarks for the device. Run with:
+#   adb shell liblog-benchmarks
+include $(CLEAR_VARS)
+LOCAL_MODULE := $(test_module_prefix)benchmarks
+LOCAL_MODULE_TAGS := $(test_tags)
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+LOCAL_CFLAGS += $(benchmark_c_flags)
+LOCAL_SHARED_LIBRARIES += liblog libm
+LOCAL_SRC_FILES := $(benchmark_src_files)
+ifndef LOCAL_SDK_VERSION
+LOCAL_C_INCLUDES += bionic bionic/libstdc++/include external/stlport/stlport
+LOCAL_SHARED_LIBRARIES += libstlport
+endif
+LOCAL_MODULE_PATH := $(TARGET_OUT_DATA_NATIVE_TESTS)/$(LOCAL_MODULE)
+include $(BUILD_EXECUTABLE)
+
+# -----------------------------------------------------------------------------
+# Unit tests.
+# -----------------------------------------------------------------------------
+
+test_c_flags := \
+    -fstack-protector-all \
+    -g \
+    -Wall -Wextra \
+    -Werror \
+    -fno-builtin \
+
+test_src_files := \
+    liblog_test.cpp \
+
+# Build tests for the device (with .so). Run with:
+#   adb shell /data/nativetest/liblog-unit-tests/liblog-unit-tests
+include $(CLEAR_VARS)
+LOCAL_MODULE := $(test_module_prefix)unit-tests
+LOCAL_MODULE_TAGS := $(test_tags)
+LOCAL_ADDITIONAL_DEPENDENCIES := $(LOCAL_PATH)/Android.mk
+LOCAL_CFLAGS += $(test_c_flags)
+LOCAL_LDLIBS := -lpthread
+LOCAL_SHARED_LIBRARIES := liblog
+LOCAL_SRC_FILES := $(test_src_files)
+include $(BUILD_NATIVE_TEST)

liblog/tests/benchmark.h

+/*
+ * Copyright (C) 2012-2014 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 <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <vector>
+
+#ifndef BIONIC_BENCHMARK_H_
+#define BIONIC_BENCHMARK_H_
+
+namespace testing {
+
+class Benchmark;
+template <typename T> class BenchmarkWantsArg;
+template <typename T> class BenchmarkWithArg;
+
+void BenchmarkRegister(Benchmark* bm);
+int PrettyPrintInt(char* str, int len, unsigned int arg);
+
+class Benchmark {
+ public:
+  Benchmark(const char* name, void (*fn)(int)) : name_(strdup(name)), fn_(fn) {
+    BenchmarkRegister(this);
+  }
+  Benchmark(const char* name) : name_(strdup(name)), fn_(NULL) {}
+
+  virtual ~Benchmark() {
+    free(name_);
+  }
+
+  const char* Name() { return name_; }
+  virtual const char* ArgName() { return NULL; }
+  virtual void RunFn(int iterations) { fn_(iterations); }
+
+ protected:
+  char* name_;
+
+ private:
+  void (*fn_)(int);
+};
+
+template <typename T>
+class BenchmarkWantsArgBase : public Benchmark {
+ public:
+  BenchmarkWantsArgBase(const char* name, void (*fn)(int, T)) : Benchmark(name) {
+    fn_arg_ = fn;
+  }
+
+  BenchmarkWantsArgBase<T>* Arg(const char* arg_name, T arg) {
+    BenchmarkRegister(new BenchmarkWithArg<T>(name_, fn_arg_, arg_name, arg));
+    return this;
+  }
+
+ protected:
+  virtual void RunFn(int) { printf("can't run arg benchmark %s without arg\n", Name()); }
+  void (*fn_arg_)(int, T);
+};
+
+template <typename T>
+class BenchmarkWithArg : public BenchmarkWantsArg<T> {
+ public:
+  BenchmarkWithArg(const char* name, void (*fn)(int, T), const char* arg_name, T arg) :
+      BenchmarkWantsArg<T>(name, fn), arg_(arg) {
+    arg_name_ = strdup(arg_name);
+  }
+
+  virtual ~BenchmarkWithArg() {
+    free(arg_name_);
+  }
+
+  virtual const char* ArgName() { return arg_name_; }
+
+ protected:
+  virtual void RunFn(int iterations) { BenchmarkWantsArg<T>::fn_arg_(iterations, arg_); }
+
+ private:
+  T arg_;
+  char* arg_name_;
+};
+
+template <typename T>
+class BenchmarkWantsArg : public BenchmarkWantsArgBase<T> {
+ public:
+  BenchmarkWantsArg<T>(const char* name, void (*fn)(int, T)) :
+    BenchmarkWantsArgBase<T>(name, fn) { }
+};
+
+template <>
+class BenchmarkWantsArg<int> : public BenchmarkWantsArgBase<int> {
+ public:
+  BenchmarkWantsArg<int>(const char* name, void (*fn)(int, int)) :
+    BenchmarkWantsArgBase<int>(name, fn) { }
+
+  BenchmarkWantsArg<int>* Arg(int arg) {
+    char arg_name[100];
+    PrettyPrintInt(arg_name, sizeof(arg_name), arg);
+    BenchmarkRegister(new BenchmarkWithArg<int>(name_, fn_arg_, arg_name, arg));
+    return this;
+  }
+};
+
+static inline Benchmark* BenchmarkFactory(const char* name, void (*fn)(int)) {
+  return new Benchmark(name, fn);
+}
+
+template <typename T>
+static inline BenchmarkWantsArg<T>* BenchmarkFactory(const char* name, void (*fn)(int, T)) {
+  return new BenchmarkWantsArg<T>(name, fn);
+}
+
+}  // namespace testing
+
+template <typename T>
+static inline void BenchmarkAddArg(::testing::Benchmark* b, const char* name, T arg) {
+  ::testing::BenchmarkWantsArg<T>* ba;
+  ba = static_cast< ::testing::BenchmarkWantsArg<T>* >(b);
+  ba->Arg(name, arg);
+}
+
+void SetBenchmarkBytesProcessed(uint64_t);
+void ResetBenchmarkTiming(void);
+void StopBenchmarkTiming(void);
+void StartBenchmarkTiming(void);
+void StartBenchmarkTiming(uint64_t);
+void StopBenchmarkTiming(uint64_t);
+
+#define BENCHMARK(f) \
+    static ::testing::Benchmark* _benchmark_##f __attribute__((unused)) = \
+        (::testing::Benchmark*)::testing::BenchmarkFactory(#f, f)
+
+#endif // BIONIC_BENCHMARK_H_

liblog/tests/benchmark_main.cpp

+/*
+ * Copyright (C) 2012-2014 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.h>
+
+#include <regex.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <string>
+#include <map>
+#include <vector>
+
+static uint64_t gBytesProcessed;
+static uint64_t gBenchmarkTotalTimeNs;
+static uint64_t gBenchmarkTotalTimeNsSquared;
+static uint64_t gBenchmarkNum;
+static uint64_t gBenchmarkStartTimeNs;
+
+typedef std::vector< ::testing::Benchmark* > BenchmarkList;
+static BenchmarkList* gBenchmarks;
+
+static int Round(int n) {
+  int base = 1;
+  while (base*10 < n) {
+    base *= 10;
+  }
+  if (n < 2*base) {
+    return 2*base;
+  }
+  if (n < 5*base) {
+    return 5*base;
+  }
+  return 10*base;
+}
+
+static uint64_t NanoTime() {
+  struct timespec t;
+  t.tv_sec = t.tv_nsec = 0;
+  clock_gettime(CLOCK_MONOTONIC, &t);
+  return static_cast<uint64_t>(t.tv_sec) * 1000000000ULL + t.tv_nsec;
+}
+
+namespace testing {
+
+int PrettyPrintInt(char* str, int len, unsigned int arg)
+{
+  if (arg >= (1<<30) && arg % (1<<30) == 0) {
+    return snprintf(str, len, "%uGi", arg/(1<<30));
+  } else if (arg >= (1<<20) && arg % (1<<20) == 0) {
+    return snprintf(str, len, "%uMi", arg/(1<<20));
+  } else if (arg >= (1<<10) && arg % (1<<10) == 0) {
+    return snprintf(str, len, "%uKi", arg/(1<<10));
+  } else if (arg >= 1000000000 && arg % 1000000000 == 0) {
+    return snprintf(str, len, "%uG", arg/1000000000);
+  } else if (arg >= 1000000 && arg % 1000000 == 0) {
+    return snprintf(str, len, "%uM", arg/1000000);
+  } else if (arg >= 1000 && arg % 1000 == 0) {
+    return snprintf(str, len, "%uK", arg/1000);
+  } else {
+    return snprintf(str, len, "%u", arg);
+  }
+}
+
+bool ShouldRun(Benchmark* b, int argc, char* argv[]) {
+  if (argc == 1) {
+    return true;  // With no arguments, we run all benchmarks.
+  }
+  // Otherwise, we interpret each argument as a regular expression and
+  // see if any of our benchmarks match.
+  for (int i = 1; i < argc; i++) {
+    regex_t re;
+    if (regcomp(&re, argv[i], 0) != 0) {
+      fprintf(stderr, "couldn't compile \"%s\" as a regular expression!\n", argv[i]);
+      exit(EXIT_FAILURE);
+    }
+    int match = regexec(&re, b->Name(), 0, NULL, 0);
+    regfree(&re);
+    if (match != REG_NOMATCH) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void BenchmarkRegister(Benchmark* b) {
+  if (gBenchmarks == NULL) {
+    gBenchmarks = new BenchmarkList;
+  }
+  gBenchmarks->push_back(b);
+}
+
+void RunRepeatedly(Benchmark* b, int iterations) {
+  gBytesProcessed = 0;
+  ResetBenchmarkTiming();
+  uint64_t StartTimeNs = NanoTime();
+  b->RunFn(iterations);
+  // Catch us if we fail to log anything.
+  if ((gBenchmarkTotalTimeNs == 0)
+   && (StartTimeNs != 0)
+   && (gBenchmarkStartTimeNs == 0)) {
+    gBenchmarkTotalTimeNs = NanoTime() - StartTimeNs;
+  }
+}
+
+void Run(Benchmark* b) {
+  // run once in case it's expensive
+  unsigned iterations = 1;
+  uint64_t s = NanoTime();
+  RunRepeatedly(b, iterations);
+  s = NanoTime() - s;
+  while (s < 2e9 && gBenchmarkTotalTimeNs < 1e9 && iterations < 1e9) {
+    unsigned last = iterations;
+    if (gBenchmarkTotalTimeNs/iterations == 0) {
+      iterations = 1e9;
+    } else {
+      iterations = 1e9 / (gBenchmarkTotalTimeNs/iterations);
+    }
+    iterations = std::max(last + 1, std::min(iterations + iterations/2, 100*last));
+    iterations = Round(iterations);
+    s = NanoTime();
+    RunRepeatedly(b, iterations);
+    s = NanoTime() - s;
+  }
+
+  char throughput[100];
+  throughput[0] = '\0';
+  if (gBenchmarkTotalTimeNs > 0 && gBytesProcessed > 0) {
+    double mib_processed = static_cast<double>(gBytesProcessed)/1e6;
+    double seconds = static_cast<double>(gBenchmarkTotalTimeNs)/1e9;
+    snprintf(throughput, sizeof(throughput), " %8.2f MiB/s", mib_processed/seconds);
+  }
+
+  char full_name[100];
+  snprintf(full_name, sizeof(full_name), "%s%s%s", b->Name(),
+           b->ArgName() ? "/" : "",
+           b->ArgName() ? b->ArgName() : "");
+
+  uint64_t mean = gBenchmarkTotalTimeNs / iterations;
+  uint64_t sdev = 0;
+  if (gBenchmarkNum == iterations) {
+    mean = gBenchmarkTotalTimeNs / gBenchmarkNum;
+    uint64_t nXvariance = gBenchmarkTotalTimeNsSquared * gBenchmarkNum
+                        - (gBenchmarkTotalTimeNs * gBenchmarkTotalTimeNs);
+    sdev = (sqrt((double)nXvariance) / gBenchmarkNum / gBenchmarkNum) + 0.5;
+  }
+  if (mean > (10000 * sdev)) {
+    printf("%-25s %10llu %10llu%s\n", full_name,
+            static_cast<uint64_t>(iterations), mean, throughput);
+  } else {
+    printf("%-25s %10llu %10llu(\317\203%llu)%s\n", full_name,
+           static_cast<uint64_t>(iterations), mean, sdev, throughput);
+  }
+  fflush(stdout);
+}
+
+}  // namespace testing
+
+void SetBenchmarkBytesProcessed(uint64_t x) {
+  gBytesProcessed = x;
+}
+
+void ResetBenchmarkTiming() {
+  gBenchmarkStartTimeNs = 0;
+  gBenchmarkTotalTimeNs = 0;
+  gBenchmarkTotalTimeNsSquared = 0;
+  gBenchmarkNum = 0;
+}
+
+void StopBenchmarkTiming(void) {
+  if (gBenchmarkStartTimeNs != 0) {
+    int64_t diff = NanoTime() - gBenchmarkStartTimeNs;
+    gBenchmarkTotalTimeNs += diff;
+    gBenchmarkTotalTimeNsSquared += diff * diff;
+    ++gBenchmarkNum;
+  }
+  gBenchmarkStartTimeNs = 0;
+}
+
+void StartBenchmarkTiming(void) {
+  if (gBenchmarkStartTimeNs == 0) {
+    gBenchmarkStartTimeNs = NanoTime();
+  }
+}
+
+void StopBenchmarkTiming(uint64_t NanoTime) {
+  if (gBenchmarkStartTimeNs != 0) {
+    int64_t diff = NanoTime - gBenchmarkStartTimeNs;
+    gBenchmarkTotalTimeNs += diff;
+    gBenchmarkTotalTimeNsSquared += diff * diff;
+    if (NanoTime != 0) {
+      ++gBenchmarkNum;
+    }
+  }
+  gBenchmarkStartTimeNs = 0;
+}
+
+void StartBenchmarkTiming(uint64_t NanoTime) {
+  if (gBenchmarkStartTimeNs == 0) {
+    gBenchmarkStartTimeNs = NanoTime;
+  }
+}
+
+int main(int argc, char* argv[]) {
+  if (gBenchmarks->empty()) {
+    fprintf(stderr, "No benchmarks registered!\n");
+    exit(EXIT_FAILURE);
+  }
+
+  bool need_header = true;
+  for (auto b : *gBenchmarks) {
+    if (ShouldRun(b, argc, argv)) {
+      if (need_header) {
+        printf("%-25s %10s %10s\n", "", "iterations", "ns/op");
+        fflush(stdout);
+        need_header = false;
+      }
+      Run(b);
+    }
+  }
+
+  if (need_header) {
+    fprintf(stderr, "No matching benchmarks!\n");
+    fprintf(stderr, "Available benchmarks:\n");
+    for (auto b : *gBenchmarks) {
+      fprintf(stderr, "  %s\n", b->Name());
+    }
+    exit(EXIT_FAILURE);
+  }
+
+  return 0;
+}

liblog/tests/liblog_benchmark.cpp

+/*
+ * Copyright (C) 2013-2014 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 <sys/socket.h>
+#include <cutils/sockets.h>
+#include <log/log.h>
+#include <log/logger.h>
+#include <log/log_read.h>
+
+#include "benchmark.h"
+
+// enhanced version of LOG_FAILURE_RETRY to add support for EAGAIN and
+// non-syscall libs. Since we are benchmarking, or using this in the emergency
+// signal to stuff a terminating code, we do NOT want to introduce
+// a syscall or usleep on EAGAIN retry.
+#define LOG_FAILURE_RETRY(exp) ({  \
+    typeof (exp) _rc;              \
+    do {                           \
+        _rc = (exp);               \
+    } while (((_rc == -1)          \
+           && ((errno == EINTR)    \
+            || (errno == EAGAIN))) \
+          || (_rc == -EINTR)       \
+          || (_rc == -EAGAIN));    \
+    _rc; })
+
+/*
+ *	Measure the fastest rate we can reliabley stuff print messages into
+ * the log at high pressure. Expect this to be less than double the process
+ * wakeup time (2ms?)
+ */
+static void BM_log_maximum_retry(int iters) {
+    StartBenchmarkTiming();
+
+    for (int i = 0; i < iters; ++i) {
+        LOG_FAILURE_RETRY(
+            __android_log_print(ANDROID_LOG_INFO,
+                                "BM_log_maximum_retry", "%d", i));
+    }
+
+    StopBenchmarkTiming();
+}
+BENCHMARK(BM_log_maximum_retry);
+
+/*
+ *	Measure the fastest rate we can stuff print messages into the log
+ * at high pressure. Expect this to be less than double the process wakeup
+ * time (2ms?)
+ */
+static void BM_log_maximum(int iters) {
+    StartBenchmarkTiming();
+
+    for (int i = 0; i < iters; ++i) {
+        __android_log_print(ANDROID_LOG_INFO, "BM_log_maximum", "%d", i);
+    }
+
+    StopBenchmarkTiming();
+}
+BENCHMARK(BM_log_maximum);
+
+/*
+ *	Measure the time it takes to submit the android logging call using
+ * discrete acquisition under light load. Expect this to be a pair of
+ * syscall periods (2us).
+ */
+static void BM_clock_overhead(int iters) {
+    for (int i = 0; i < iters; ++i) {
+       StartBenchmarkTiming();
+       StopBenchmarkTiming();
+    }
+}
+BENCHMARK(BM_clock_overhead);
+
+/*
+ *	Measure the time it takes to submit the android logging call using
+ * discrete acquisition under light load. Expect this to be a dozen or so
+ * syscall periods (40us).
+ */
+static void BM_log_overhead(int iters) {
+    for (int i = 0; i < iters; ++i) {
+       StartBenchmarkTiming();
+       __android_log_print(ANDROID_LOG_INFO, "BM_log_overhead", "%d", i);
+       StopBenchmarkTiming();
+       usleep(1000);
+    }
+}
+BENCHMARK(BM_log_overhead);
+
+static void caught_latency(int signum)
+{
+    unsigned long long v = 0xDEADBEEFA55A5AA5ULL;
+
+    LOG_FAILURE_RETRY(__android_log_btwrite(0, EVENT_TYPE_LONG, &v, sizeof(v)));
+}
+
+static unsigned long long caught_convert(char *cp)
+{
+    unsigned long long l = cp[0] & 0xFF;
+    l |= (unsigned long long) (cp[1] & 0xFF) << 8;
+    l |= (unsigned long long) (cp[2] & 0xFF) << 16;
+    l |= (unsigned long long) (cp[3] & 0xFF) << 24;
+    l |= (unsigned long long) (cp[4] & 0xFF) << 32;
+    l |= (unsigned long long) (cp[5] & 0xFF) << 40;
+    l |= (unsigned long long) (cp[6] & 0xFF) << 48;
+    l |= (unsigned long long) (cp[7] & 0xFF) << 56;
+    return l;
+}
+
+static const int alarm_time = 3;
+
+/*
+ *	Measure the time it takes for the logd posting call to acquire the
+ * timestamp to place into the internal record. Expect this to be less than
+ * 4 syscalls (3us).
+ */
+static void BM_log_latency(int iters) {
+    pid_t pid = getpid();
+
+    struct logger_list * logger_list = android_logger_list_open(LOG_ID_EVENTS,
+        O_RDONLY, 0, pid);
+
+    if (!logger_list) {
+        fprintf(stderr, "Unable to open events log: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    signal(SIGALRM, caught_latency);
+    alarm(alarm_time);
+
+    for (int j = 0, i = 0; i < iters && j < 10*iters; ++i, ++j) {
+        log_time ts;
+        LOG_FAILURE_RETRY((
+            clock_gettime(CLOCK_REALTIME, &ts),
+            android_btWriteLog(0, EVENT_TYPE_LONG, &ts, sizeof(ts))));
+
+        for (;;) {
+            log_msg log_msg;
+            int ret = android_logger_list_read(logger_list, &log_msg);
+            alarm(alarm_time);
+
+            if (ret <= 0) {
+                iters = i;
+                break;
+            }
+            if ((log_msg.entry.len != (4 + 1 + 8))
+             || (log_msg.id() != LOG_ID_EVENTS)) {
+                continue;
+            }
+
+            char* eventData = log_msg.msg();
+
+            if (eventData[4] != EVENT_TYPE_LONG) {
+                continue;
+            }
+            log_time tx(eventData + 4 + 1);
+            if (ts != tx) {
+                if (0xDEADBEEFA55A5AA5ULL == caught_convert(eventData + 4 + 1)) {
+                    iters = i;
+                    break;
+                }
+                continue;
+            }
+
+            uint64_t start = ts.nsec();
+            uint64_t end = log_msg.nsec();
+            if (end >= start) {
+                StartBenchmarkTiming(start);
+                StopBenchmarkTiming(end);
+            } else {
+                --i;
+            }
+            break;
+        }
+    }
+
+    signal(SIGALRM, SIG_DFL);
+    alarm(0);
+
+    android_logger_list_free(logger_list);
+}
+BENCHMARK(BM_log_latency);
+
+static void caught_delay(int signum)
+{
+    unsigned long long v = 0xDEADBEEFA55A5AA6ULL;
+
+    LOG_FAILURE_RETRY(__android_log_btwrite(0, EVENT_TYPE_LONG, &v, sizeof(v)));
+}
+
+/*
+ *	Measure the time it takes for the logd posting call to make it into
+ * the logs. Expect this to be less than double the process wakeup time (2ms).
+ */
+static void BM_log_delay(int iters) {
+    pid_t pid = getpid();
+
+    struct logger_list * logger_list = android_logger_list_open(LOG_ID_EVENTS,
+        O_RDONLY, 0, pid);
+
+    if (!logger_list) {
+        fprintf(stderr, "Unable to open events log: %s\n", strerror(errno));
+        exit(EXIT_FAILURE);
+    }
+
+    signal(SIGALRM, caught_delay);
+    alarm(alarm_time);
+
+    StartBenchmarkTiming();
+
+    for (int i = 0; i < iters; ++i) {
+        log_time ts(CLOCK_REALTIME);
+
+        LOG_FAILURE_RETRY(
+            android_btWriteLog(0, EVENT_TYPE_LONG, &ts, sizeof(ts)));
+
+        for (;;) {
+            log_msg log_msg;
+            int ret = android_logger_list_read(logger_list, &log_msg);
+            alarm(alarm_time);
+
+            if (ret <= 0) {
+                iters = i;
+                break;
+            }
+            if ((log_msg.entry.len != (4 + 1 + 8))
+             || (log_msg.id() != LOG_ID_EVENTS)) {
+                continue;
+            }
+
+            char* eventData = log_msg.msg();
+
+            if (eventData[4] != EVENT_TYPE_LONG) {
+                continue;
+            }
+            log_time tx(eventData + 4 + 1);
+            if (ts != tx) {
+                if (0xDEADBEEFA55A5AA6ULL == caught_convert(eventData + 4 + 1)) {
+                    iters = i;
+                    break;
+                }
+                continue;
+            }
+
+            break;
+        }
+    }
+
+    signal(SIGALRM, SIG_DFL);
+    alarm(0);
+
+    StopBenchmarkTiming();
+
+    android_logger_list_free(logger_list);
+}
+BENCHMARK(BM_log_delay);

liblog/tests/liblog_test.cpp

+/*
+ * Copyright (C) 2013-2014 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 <fcntl.h>
+#include <gtest/gtest.h>
+#include <log/log.h>
+#include <log/logger.h>
+#include <log/log_read.h>
+
+TEST(liblog, __android_log_buf_print) {
+    ASSERT_LT(0, __android_log_buf_print(LOG_ID_RADIO, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_print",
+                                         "radio"));
+    usleep(1000);
+    ASSERT_LT(0, __android_log_buf_print(LOG_ID_SYSTEM, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_print",
+                                         "system"));
+    usleep(1000);
+    ASSERT_LT(0, __android_log_buf_print(LOG_ID_MAIN, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_print",
+                                         "main"));
+    usleep(1000);
+}
+
+TEST(liblog, __android_log_buf_write) {
+    ASSERT_LT(0, __android_log_buf_write(LOG_ID_RADIO, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_write",
+                                         "radio"));
+    usleep(1000);
+    ASSERT_LT(0, __android_log_buf_write(LOG_ID_SYSTEM, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_write",
+                                         "system"));
+    usleep(1000);
+    ASSERT_LT(0, __android_log_buf_write(LOG_ID_MAIN, ANDROID_LOG_INFO,
+                                         "TEST__android_log_buf_write",
+                                         "main"));
+    usleep(1000);
+}
+
+TEST(liblog, __android_log_btwrite) {
+    int intBuf = 0xDEADBEEF;
+    ASSERT_LT(0, __android_log_btwrite(0,
+                                      EVENT_TYPE_INT,
+                                      &intBuf, sizeof(intBuf)));
+    long long longBuf = 0xDEADBEEFA55A5AA5;
+    ASSERT_LT(0, __android_log_btwrite(0,
+                                      EVENT_TYPE_LONG,
+                                      &longBuf, sizeof(longBuf)));
+    usleep(1000);
+    char Buf[] = "\20\0\0\0DeAdBeEfA55a5aA5";
+    ASSERT_LT(0, __android_log_btwrite(0,
+                                      EVENT_TYPE_STRING,
+                                      Buf, sizeof(Buf) - 1));
+    usleep(1000);
+}
+
+static void* ConcurrentPrintFn(void *arg) {
+    int ret = __android_log_buf_print(LOG_ID_MAIN, ANDROID_LOG_INFO,
+                                  "TEST__android_log_print", "Concurrent %d",
+                                  reinterpret_cast<int>(arg));
+    return reinterpret_cast<void*>(ret);
+}
+
+#define NUM_CONCURRENT 64
+#define _concurrent_name(a,n) a##__concurrent##n
+#define concurrent_name(a,n) _concurrent_name(a,n)
+
+TEST(liblog, concurrent_name(__android_log_buf_print, NUM_CONCURRENT)) {
+    pthread_t t[NUM_CONCURRENT];
+    int i;
+    for (i=0; i < NUM_CONCURRENT; i++) {
+        ASSERT_EQ(0, pthread_create(&t[i], NULL,
+                                    ConcurrentPrintFn,
+                                    reinterpret_cast<void *>(i)));
+    }
+    int ret = 0;
+    for (i=0; i < NUM_CONCURRENT; i++) {
+        void* result;
+        ASSERT_EQ(0, pthread_join(t[i], &result));
+        if ((0 == ret) && (0 != reinterpret_cast<int>(result))) {
+            ret = reinterpret_cast<int>(result);
+        }
+    }
+    ASSERT_LT(0, ret);
+}
+
+TEST(liblog, __android_log_btwrite__android_logger_list_read) {
+    struct logger_list *logger_list;
+
+    pid_t pid = getpid();
+
+    ASSERT_EQ(0, NULL == (logger_list = android_logger_list_open(
+        LOG_ID_EVENTS, O_RDONLY | O_NDELAY, 1000, pid)));
+
+    log_time ts(CLOCK_MONOTONIC);
+
+    ASSERT_LT(0, __android_log_btwrite(0, EVENT_TYPE_LONG, &ts, sizeof(ts)));
+    usleep(1000000);
+
+    int count = 0;
+
+    for (;;) {
+        log_msg log_msg;
+        if (android_logger_list_read(logger_list, &log_msg) <= 0) {
+            break;
+        }
+
+        ASSERT_EQ(log_msg.entry.pid, pid);
+
+        if ((log_msg.entry.len != (4 + 1 + 8))
+         || (log_msg.id() != LOG_ID_EVENTS)) {
+            continue;
+        }
+
+        char *eventData = log_msg.msg();
+
+        if (eventData[4] != EVENT_TYPE_LONG) {
+            continue;
+        }
+
+        log_time tx(eventData + 4 + 1);
+        if (ts == tx) {
+            ++count;
+        }
+    }
+
+    ASSERT_EQ(1, count);
+
+    android_logger_list_close(logger_list);
+}
+
+TEST(liblog, android_logger_get_) {
+    struct logger_list * logger_list = android_logger_list_alloc(O_WRONLY, 0, 0);
+
+    for(int i = LOG_ID_MIN; i < LOG_ID_MAX; ++i) {
+        log_id_t id = static_cast<log_id_t>(i);
+        const char *name = android_log_id_to_name(id);
+        if (id != android_name_to_log_id(name)) {
+            continue;
+        }
+        struct logger * logger;
+        ASSERT_EQ(0, NULL == (logger = android_logger_open(logger_list, id)));
+        ASSERT_EQ(id, android_logger_get_id(logger));
+        ASSERT_LT(0, android_logger_get_log_size(logger));
+        ASSERT_LT(0, android_logger_get_log_readable_size(logger));
+        ASSERT_LT(0, android_logger_get_log_version(logger));
+    }
+
+    android_logger_list_close(logger_list);
+}