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 <fcntl.h>
#include <inttypes.h>
#include <poll.h>
#include <sys/endian.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <unistd.h>

#include <unordered_set>

#include <android-base/file.h>
#include <cutils/sockets.h>
#include <log/event_tag_map.h>
#include <log/log_transport.h>
#include <private/android_logger.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);

static void set_log_null() {
  android_set_log_transport(LOGGER_NULL);
}

static void set_log_default() {
  android_set_log_transport(LOGGER_DEFAULT);
}

static void BM_log_maximum_null(int iters) {
  set_log_null();
  BM_log_maximum(iters);
  set_log_default();
}
BENCHMARK(BM_log_maximum_null);

/*
 *	Measure the time it takes to collect the time using
 * discrete acquisition (StartBenchmarkTiming() -> StopBenchmarkTiming())
 * under light load. Expect this to be a syscall period (2us) or
 * data read time if zero-syscall.
 *
 * vdso support in the kernel and the library can allow
 * clock_gettime to be zero-syscall.
 */
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 data to pstore
 */
static void BM_pmsg_short(int iters) {
  int pstore_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY));
  if (pstore_fd < 0) {
    return;
  }

  /*
   *  struct {
   *      // what we provide to pstore
   *      android_pmsg_log_header_t pmsg_header;
   *      // what we provide to socket
   *      android_log_header_t header;
   *      // caller provides
   *      union {
   *          struct {
   *              char     prio;
   *              char     payload[];
   *          } string;
   *          struct {
   *              uint32_t tag
   *              char     payload[];
   *          } binary;
   *      };
   *  };
   */

  struct timespec ts;
  clock_gettime(android_log_clockid(), &ts);

  android_pmsg_log_header_t pmsg_header;
  pmsg_header.magic = LOGGER_MAGIC;
  pmsg_header.len =
      sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t);
  pmsg_header.uid = getuid();
  pmsg_header.pid = getpid();

  android_log_header_t header;
  header.tid = gettid();
  header.realtime.tv_sec = ts.tv_sec;
  header.realtime.tv_nsec = ts.tv_nsec;

  static const unsigned nr = 1;
  static const unsigned header_length = 2;
  struct iovec newVec[nr + header_length];

  newVec[0].iov_base = (unsigned char*)&pmsg_header;
  newVec[0].iov_len = sizeof(pmsg_header);
  newVec[1].iov_base = (unsigned char*)&header;
  newVec[1].iov_len = sizeof(header);

  android_log_event_int_t buffer;

  header.id = LOG_ID_EVENTS;
  buffer.header.tag = 0;
  buffer.payload.type = EVENT_TYPE_INT;
  uint32_t snapshot = 0;
  buffer.payload.data = htole32(snapshot);

  newVec[2].iov_base = &buffer;
  newVec[2].iov_len = sizeof(buffer);

  StartBenchmarkTiming();
  for (int i = 0; i < iters; ++i) {
    ++snapshot;
    buffer.payload.data = htole32(snapshot);
    writev(pstore_fd, newVec, nr);
  }
  StopBenchmarkTiming();
  close(pstore_fd);
}
BENCHMARK(BM_pmsg_short);

/*
 * Measure the time it takes to submit the android logging data to pstore
 * best case aligned single block.
 */
static void BM_pmsg_short_aligned(int iters) {
  int pstore_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY));
  if (pstore_fd < 0) {
    return;
  }

  /*
   *  struct {
   *      // what we provide to pstore
   *      android_pmsg_log_header_t pmsg_header;
   *      // what we provide to socket
   *      android_log_header_t header;
   *      // caller provides
   *      union {
   *          struct {
   *              char     prio;
   *              char     payload[];
   *          } string;
   *          struct {
   *              uint32_t tag
   *              char     payload[];
   *          } binary;
   *      };
   *  };
   */

  struct timespec ts;
  clock_gettime(android_log_clockid(), &ts);

  struct packet {
    android_pmsg_log_header_t pmsg_header;
    android_log_header_t header;
    android_log_event_int_t payload;
  };
  alignas(8) char buf[sizeof(struct packet) + 8];
  memset(buf, 0, sizeof(buf));
  struct packet* buffer = (struct packet*)(((uintptr_t)buf + 7) & ~7);
  if (((uintptr_t)&buffer->pmsg_header) & 7) {
    fprintf(stderr, "&buffer=0x%p iters=%d\n", &buffer->pmsg_header, iters);
  }

  buffer->pmsg_header.magic = LOGGER_MAGIC;
  buffer->pmsg_header.len =
      sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t);
  buffer->pmsg_header.uid = getuid();
  buffer->pmsg_header.pid = getpid();

  buffer->header.tid = gettid();
  buffer->header.realtime.tv_sec = ts.tv_sec;
  buffer->header.realtime.tv_nsec = ts.tv_nsec;

  buffer->header.id = LOG_ID_EVENTS;
  buffer->payload.header.tag = 0;
  buffer->payload.payload.type = EVENT_TYPE_INT;
  uint32_t snapshot = 0;
  buffer->payload.payload.data = htole32(snapshot);

  StartBenchmarkTiming();
  for (int i = 0; i < iters; ++i) {
    ++snapshot;
    buffer->payload.payload.data = htole32(snapshot);
    write(pstore_fd, &buffer->pmsg_header,
          sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t) +
              sizeof(android_log_event_int_t));
  }
  StopBenchmarkTiming();
  close(pstore_fd);
}
BENCHMARK(BM_pmsg_short_aligned);

/*
 * Measure the time it takes to submit the android logging data to pstore
 * best case aligned single block.
 */
static void BM_pmsg_short_unaligned1(int iters) {
  int pstore_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY));
  if (pstore_fd < 0) {
    return;
  }

  /*
   *  struct {
   *      // what we provide to pstore
   *      android_pmsg_log_header_t pmsg_header;
   *      // what we provide to socket
   *      android_log_header_t header;
   *      // caller provides
   *      union {
   *          struct {
   *              char     prio;
   *              char     payload[];
   *          } string;
   *          struct {
   *              uint32_t tag
   *              char     payload[];
   *          } binary;
   *      };
   *  };
   */

  struct timespec ts;
  clock_gettime(android_log_clockid(), &ts);

  struct packet {
    android_pmsg_log_header_t pmsg_header;
    android_log_header_t header;
    android_log_event_int_t payload;
  };
  alignas(8) char buf[sizeof(struct packet) + 8];
  memset(buf, 0, sizeof(buf));
  struct packet* buffer = (struct packet*)((((uintptr_t)buf + 7) & ~7) + 1);
  if ((((uintptr_t)&buffer->pmsg_header) & 7) != 1) {
    fprintf(stderr, "&buffer=0x%p iters=%d\n", &buffer->pmsg_header, iters);
  }

  buffer->pmsg_header.magic = LOGGER_MAGIC;
  buffer->pmsg_header.len =
      sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t);
  buffer->pmsg_header.uid = getuid();
  buffer->pmsg_header.pid = getpid();

  buffer->header.tid = gettid();
  buffer->header.realtime.tv_sec = ts.tv_sec;
  buffer->header.realtime.tv_nsec = ts.tv_nsec;

  buffer->header.id = LOG_ID_EVENTS;
  buffer->payload.header.tag = 0;
  buffer->payload.payload.type = EVENT_TYPE_INT;
  uint32_t snapshot = 0;
  buffer->payload.payload.data = htole32(snapshot);

  StartBenchmarkTiming();
  for (int i = 0; i < iters; ++i) {
    ++snapshot;
    buffer->payload.payload.data = htole32(snapshot);
    write(pstore_fd, &buffer->pmsg_header,
          sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t) +
              sizeof(android_log_event_int_t));
  }
  StopBenchmarkTiming();
  close(pstore_fd);
}
BENCHMARK(BM_pmsg_short_unaligned1);

/*
 * Measure the time it takes to submit the android logging data to pstore
 * best case aligned single block.
 */
static void BM_pmsg_long_aligned(int iters) {
  int pstore_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY));
  if (pstore_fd < 0) {
    return;
  }

  /*
   *  struct {
   *      // what we provide to pstore
   *      android_pmsg_log_header_t pmsg_header;
   *      // what we provide to socket
   *      android_log_header_t header;
   *      // caller provides
   *      union {
   *          struct {
   *              char     prio;
   *              char     payload[];
   *          } string;
   *          struct {
   *              uint32_t tag
   *              char     payload[];
   *          } binary;
   *      };
   *  };
   */

  struct timespec ts;
  clock_gettime(android_log_clockid(), &ts);

  struct packet {
    android_pmsg_log_header_t pmsg_header;
    android_log_header_t header;
    android_log_event_int_t payload;
  };
  alignas(8) char buf[sizeof(struct packet) + 8 + LOGGER_ENTRY_MAX_PAYLOAD];
  memset(buf, 0, sizeof(buf));
  struct packet* buffer = (struct packet*)(((uintptr_t)buf + 7) & ~7);
  if (((uintptr_t)&buffer->pmsg_header) & 7) {
    fprintf(stderr, "&buffer=0x%p iters=%d\n", &buffer->pmsg_header, iters);
  }

  buffer->pmsg_header.magic = LOGGER_MAGIC;
  buffer->pmsg_header.len =
      sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t);
  buffer->pmsg_header.uid = getuid();
  buffer->pmsg_header.pid = getpid();

  buffer->header.tid = gettid();
  buffer->header.realtime.tv_sec = ts.tv_sec;
  buffer->header.realtime.tv_nsec = ts.tv_nsec;

  buffer->header.id = LOG_ID_EVENTS;
  buffer->payload.header.tag = 0;
  buffer->payload.payload.type = EVENT_TYPE_INT;
  uint32_t snapshot = 0;
  buffer->payload.payload.data = htole32(snapshot);

  StartBenchmarkTiming();
  for (int i = 0; i < iters; ++i) {
    ++snapshot;
    buffer->payload.payload.data = htole32(snapshot);
    write(pstore_fd, &buffer->pmsg_header, LOGGER_ENTRY_MAX_PAYLOAD);
  }
  StopBenchmarkTiming();
  close(pstore_fd);
}
BENCHMARK(BM_pmsg_long_aligned);

/*
 * Measure the time it takes to submit the android logging data to pstore
 * best case aligned single block.
 */
static void BM_pmsg_long_unaligned1(int iters) {
  int pstore_fd = TEMP_FAILURE_RETRY(open("/dev/pmsg0", O_WRONLY));
  if (pstore_fd < 0) {
    return;
  }

  /*
   *  struct {
   *      // what we provide to pstore
   *      android_pmsg_log_header_t pmsg_header;
   *      // what we provide to socket
   *      android_log_header_t header;
   *      // caller provides
   *      union {
   *          struct {
   *              char     prio;
   *              char     payload[];
   *          } string;
   *          struct {
   *              uint32_t tag
   *              char     payload[];
   *          } binary;
   *      };
   *  };
   */

  struct timespec ts;
  clock_gettime(android_log_clockid(), &ts);

  struct packet {
    android_pmsg_log_header_t pmsg_header;
    android_log_header_t header;
    android_log_event_int_t payload;
  };
  alignas(8) char buf[sizeof(struct packet) + 8 + LOGGER_ENTRY_MAX_PAYLOAD];
  memset(buf, 0, sizeof(buf));
  struct packet* buffer = (struct packet*)((((uintptr_t)buf + 7) & ~7) + 1);
  if ((((uintptr_t)&buffer->pmsg_header) & 7) != 1) {
    fprintf(stderr, "&buffer=0x%p iters=%d\n", &buffer->pmsg_header, iters);
  }

  buffer->pmsg_header.magic = LOGGER_MAGIC;
  buffer->pmsg_header.len =
      sizeof(android_pmsg_log_header_t) + sizeof(android_log_header_t);
  buffer->pmsg_header.uid = getuid();
  buffer->pmsg_header.pid = getpid();

  buffer->header.tid = gettid();
  buffer->header.realtime.tv_sec = ts.tv_sec;
  buffer->header.realtime.tv_nsec = ts.tv_nsec;

  buffer->header.id = LOG_ID_EVENTS;
  buffer->payload.header.tag = 0;
  buffer->payload.payload.type = EVENT_TYPE_INT;
  uint32_t snapshot = 0;
  buffer->payload.payload.data = htole32(snapshot);

  StartBenchmarkTiming();
  for (int i = 0; i < iters; ++i) {
    ++snapshot;
    buffer->payload.payload.data = htole32(snapshot);
    write(pstore_fd, &buffer->pmsg_header, LOGGER_ENTRY_MAX_PAYLOAD);
  }
  StopBenchmarkTiming();
  close(pstore_fd);
}
BENCHMARK(BM_pmsg_long_unaligned1);

/*
 *	Measure the time it takes to form sprintf plus time using
 * discrete acquisition (StartBenchmarkTiming() -> StopBenchmarkTiming())
 * under light load. Expect this to be a syscall period (2us) or sprintf
 * time if zero-syscall time.
 */
/* helper function */
static void test_print(const char* fmt, ...) {
  va_list ap;
  char buf[1024];

  va_start(ap, fmt);
  vsnprintf(buf, sizeof(buf), fmt, ap);
  va_end(ap);
}

#define logd_yield() sched_yield()  // allow logd to catch up
#define logd_sleep() usleep(50)     // really allow logd to catch up

/* performance test */
static void BM_sprintf_overhead(int iters) {
  for (int i = 0; i < iters; ++i) {
    StartBenchmarkTiming();
    test_print("BM_sprintf_overhead:%d", i);
    StopBenchmarkTiming();
    logd_yield();
  }
}
BENCHMARK(BM_sprintf_overhead);

/*
 *	Measure the time it takes to submit the android printing logging call
 * using discrete acquisition discrete acquisition (StartBenchmarkTiming() ->
 * StopBenchmarkTiming()) under light load. Expect this to be a dozen or so
 * syscall periods (40us) plus time to run *printf
 */
static void BM_log_print_overhead(int iters) {
  for (int i = 0; i < iters; ++i) {
    StartBenchmarkTiming();
    __android_log_print(ANDROID_LOG_INFO, "BM_log_overhead", "%d", i);
    StopBenchmarkTiming();
    logd_yield();
  }
}
BENCHMARK(BM_log_print_overhead);

/*
 *	Measure the time it takes to submit the android event logging call
 * using discrete acquisition (StartBenchmarkTiming() -> StopBenchmarkTiming())
 * under light load. Expect this to be a dozen or so syscall periods (40us)
 */
static void BM_log_event_overhead(int iters) {
  for (unsigned long long i = 0; i < (unsigned)iters; ++i) {
    StartBenchmarkTiming();
    __android_log_btwrite(0, EVENT_TYPE_LONG, &i, sizeof(i));
    StopBenchmarkTiming();
    logd_yield();
  }
}
BENCHMARK(BM_log_event_overhead);

static void BM_log_event_overhead_null(int iters) {
  set_log_null();
  BM_log_event_overhead(iters);
  set_log_default();
}
BENCHMARK(BM_log_event_overhead_null);

/*
 *	Measure the time it takes to submit the android event logging call
 * using discrete acquisition (StartBenchmarkTiming() -> StopBenchmarkTiming())
 * under very-light load (<1% CPU utilization).
 */
static void BM_log_light_overhead(int iters) {
  for (unsigned long long i = 0; i < (unsigned)iters; ++i) {
    StartBenchmarkTiming();
    __android_log_btwrite(0, EVENT_TYPE_LONG, &i, sizeof(i));
    StopBenchmarkTiming();
    usleep(10000);
  }
}
BENCHMARK(BM_log_light_overhead);

static void BM_log_light_overhead_null(int iters) {
  set_log_null();
  BM_log_light_overhead(iters);
  set_log_default();
}
BENCHMARK(BM_log_light_overhead_null);

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, ANDROID_LOG_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((ts = log_time(CLOCK_REALTIME),
                       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 || (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, ANDROID_LOG_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 || (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);

/*
 *	Measure the time it takes for __android_log_is_loggable.
 */
static void BM_is_loggable(int iters) {
  static const char logd[] = "logd";

  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    __android_log_is_loggable_len(ANDROID_LOG_WARN, logd, strlen(logd),
                                  ANDROID_LOG_VERBOSE);
  }

  StopBenchmarkTiming();
}
BENCHMARK(BM_is_loggable);

/*
 *	Measure the time it takes for android_log_clockid.
 */
static void BM_clockid(int iters) {
  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    android_log_clockid();
  }

  StopBenchmarkTiming();
}
BENCHMARK(BM_clockid);

/*
 *	Measure the time it takes for __android_log_security.
 */
static void BM_security(int iters) {
  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    __android_log_security();
  }

  StopBenchmarkTiming();
}
BENCHMARK(BM_security);

// Keep maps around for multiple iterations
static std::unordered_set<uint32_t> set;
static EventTagMap* map;

static bool prechargeEventMap() {
  if (map) return true;

  fprintf(stderr, "Precharge: start\n");

  map = android_openEventTagMap(NULL);
  for (uint32_t tag = 1; tag < USHRT_MAX; ++tag) {
    size_t len;
    if (android_lookupEventTag_len(map, &len, tag) == NULL) continue;
    set.insert(tag);
  }

  fprintf(stderr, "Precharge: stop %zu\n", set.size());

  return true;
}

/*
 *	Measure the time it takes for android_lookupEventTag_len
 */
static void BM_lookupEventTag(int iters) {
  prechargeEventMap();

  std::unordered_set<uint32_t>::const_iterator it = set.begin();

  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    size_t len;
    android_lookupEventTag_len(map, &len, (*it));
    ++it;
    if (it == set.end()) it = set.begin();
  }

  StopBenchmarkTiming();
}
BENCHMARK(BM_lookupEventTag);

/*
 *	Measure the time it takes for android_lookupEventTag_len
 */
static uint32_t notTag = 1;

static void BM_lookupEventTag_NOT(int iters) {
  prechargeEventMap();

  while (set.find(notTag) != set.end()) {
    ++notTag;
    if (notTag >= USHRT_MAX) notTag = 1;
  }

  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    size_t len;
    android_lookupEventTag_len(map, &len, notTag);
  }

  StopBenchmarkTiming();

  ++notTag;
  if (notTag >= USHRT_MAX) notTag = 1;
}
BENCHMARK(BM_lookupEventTag_NOT);

/*
 *	Measure the time it takes for android_lookupEventFormat_len
 */
static void BM_lookupEventFormat(int iters) {
  prechargeEventMap();

  std::unordered_set<uint32_t>::const_iterator it = set.begin();

  StartBenchmarkTiming();

  for (int i = 0; i < iters; ++i) {
    size_t len;
    android_lookupEventFormat_len(map, &len, (*it));
    ++it;
    if (it == set.end()) it = set.begin();
  }

  StopBenchmarkTiming();
}
BENCHMARK(BM_lookupEventFormat);

/*
 *	Measure the time it takes for android_lookupEventTagNum plus above
 */
static void BM_lookupEventTagNum(int iters) {
  prechargeEventMap();

  std::unordered_set<uint32_t>::const_iterator it = set.begin();

  for (int i = 0; i < iters; ++i) {
    size_t len;
    const char* name = android_lookupEventTag_len(map, &len, (*it));
    std::string Name(name, len);
    const char* format = android_lookupEventFormat_len(map, &len, (*it));
    std::string Format(format, len);
    StartBenchmarkTiming();
    android_lookupEventTagNum(map, Name.c_str(), Format.c_str(),
                              ANDROID_LOG_UNKNOWN);
    StopBenchmarkTiming();
    ++it;
    if (it == set.end()) it = set.begin();
  }
}
BENCHMARK(BM_lookupEventTagNum);

// Must be functionally identical to liblog internal __send_log_msg.
static void send_to_control(char* buf, size_t len) {
  int sock = socket_local_client("logd", ANDROID_SOCKET_NAMESPACE_RESERVED,
                                 SOCK_STREAM);
  if (sock < 0) return;
  size_t writeLen = strlen(buf) + 1;

  ssize_t ret = TEMP_FAILURE_RETRY(write(sock, buf, writeLen));
  if (ret <= 0) {
    close(sock);
    return;
  }
  while ((ret = read(sock, buf, len)) > 0) {
    if (((size_t)ret == len) || (len < PAGE_SIZE)) {
      break;
    }
    len -= ret;
    buf += ret;

    struct pollfd p = {.fd = sock, .events = POLLIN, .revents = 0 };

    ret = poll(&p, 1, 20);
    if ((ret <= 0) || !(p.revents & POLLIN)) {
      break;
    }
  }
  close(sock);
}

static void BM_lookupEventTagNum_logd_new(int iters) {
  fprintf(stderr,
          "WARNING: "
          "This test can cause logd to grow in size and hit DOS limiter\n");
  // Make copies
  static const char empty_event_log_tags[] = "# content owned by logd\n";
  static const char dev_event_log_tags_path[] = "/dev/event-log-tags";
  std::string dev_event_log_tags;
  if (android::base::ReadFileToString(dev_event_log_tags_path,
                                      &dev_event_log_tags) &&
      (dev_event_log_tags.length() == 0)) {
    dev_event_log_tags = empty_event_log_tags;
  }
  static const char data_event_log_tags_path[] =
      "/data/misc/logd/event-log-tags";
  std::string data_event_log_tags;
  if (android::base::ReadFileToString(data_event_log_tags_path,
                                      &data_event_log_tags) &&
      (data_event_log_tags.length() == 0)) {
    data_event_log_tags = empty_event_log_tags;
  }

  for (int i = 0; i < iters; ++i) {
    char buffer[256];
    memset(buffer, 0, sizeof(buffer));
    log_time now(CLOCK_MONOTONIC);
    char name[64];
    snprintf(name, sizeof(name), "a%" PRIu64, now.nsec());
    snprintf(buffer, sizeof(buffer), "getEventTag name=%s format=\"(new|1)\"",
             name);
    StartBenchmarkTiming();
    send_to_control(buffer, sizeof(buffer));
    StopBenchmarkTiming();
  }

  // Restore copies (logd still know about them, until crash or reboot)
  if (dev_event_log_tags.length() &&
      !android::base::WriteStringToFile(dev_event_log_tags,
                                        dev_event_log_tags_path)) {
    fprintf(stderr,
            "WARNING: "
            "failed to restore %s\n",
            dev_event_log_tags_path);
  }
  if (data_event_log_tags.length() &&
      !android::base::WriteStringToFile(data_event_log_tags,
                                        data_event_log_tags_path)) {
    fprintf(stderr,
            "WARNING: "
            "failed to restore %s\n",
            data_event_log_tags_path);
  }
  fprintf(stderr,
          "WARNING: "
          "Restarting logd to make it forget what we just did\n");
  system("stop logd ; start logd");
}
BENCHMARK(BM_lookupEventTagNum_logd_new);

static void BM_lookupEventTagNum_logd_existing(int iters) {
  prechargeEventMap();

  std::unordered_set<uint32_t>::const_iterator it = set.begin();

  for (int i = 0; i < iters; ++i) {
    size_t len;
    const char* name = android_lookupEventTag_len(map, &len, (*it));
    std::string Name(name, len);
    const char* format = android_lookupEventFormat_len(map, &len, (*it));
    std::string Format(format, len);

    char buffer[256];
    snprintf(buffer, sizeof(buffer), "getEventTag name=%s format=\"%s\"",
             Name.c_str(), Format.c_str());

    StartBenchmarkTiming();
    send_to_control(buffer, sizeof(buffer));
    StopBenchmarkTiming();
    ++it;
    if (it == set.end()) it = set.begin();
  }
}
BENCHMARK(BM_lookupEventTagNum_logd_existing);