Refactor the benchmark code.

Changes:
- Modify the benchmarks to derive from a single Benchmark object.
- Rewrite the main iteration code. This includes changing the iteration
  code to use the actual total time calculated by the benchmark as a basis
  for determining whether there are enough iterations instead of using
  the time it takes to run the benchmark.
- Allow benchmarks to take no argument, int, or double.
- Fix the PrettyInt printer for negative integers.
- Modify the max column width name to include the whole name including
  the arg part.
- Reformat property_benchmark.cpp in line with the rest of the code.
- Modify a few of the math benchmarks to take an argument instead of
  separate benchmarks for the same function with different args.
- Create a vector of regex_t structs to represent the args all at
  once instead of when running each benchmark.

This change is in preparation for adding new math based benchmarks.

Tested by running on a nexus flo running at max using the new code
and the old code and comparing. All of the numbers are similar, but
some of the iterations are different due to the slightly different
algorithm used.

Change-Id: I57ad1f3ff083282b9ffeb72e687cab369ce3523a

1 files changed, 8 insertions, 106 deletions

diff --git a/benchmarks/semaphore_benchmark.cpp b/benchmarks/semaphore_benchmark.cpp
index 974b0460e..8dd56849d 100644
--- a/benchmarks/semaphore_benchmark.cpp
+++ b/benchmarks/semaphore_benchmark.cpp
@@ -14,14 +14,15 @@
  * limitations under the License.
  */
 
-#include "benchmark.h"
-
 #include <pthread.h>
 #include <semaphore.h>
 #include <stdatomic.h>
 #include <stdio.h>
 
-static void BM_semaphore_sem_getvalue(int iters) {
+#include <benchmark/Benchmark.h>
+
+BENCHMARK_NO_ARG(BM_semaphore_sem_getvalue);
+void BM_semaphore_sem_getvalue::Run(int iters) {
   StopBenchmarkTiming();
   sem_t semaphore;
   sem_init(&semaphore, 1, 1);
@@ -34,9 +35,9 @@ static void BM_semaphore_sem_getvalue(int iters) {
 
   StopBenchmarkTiming();
 }
-BENCHMARK(BM_semaphore_sem_getvalue);
 
-static void BM_semaphore_sem_wait_sem_post(int iters) {
+BENCHMARK_NO_ARG(BM_semaphore_sem_wait_sem_post);
+void BM_semaphore_sem_wait_sem_post::Run(int iters) {
   StopBenchmarkTiming();
   sem_t semaphore;
   sem_init(&semaphore, 1, 1);
@@ -49,7 +50,6 @@ static void BM_semaphore_sem_wait_sem_post(int iters) {
 
   StopBenchmarkTiming();
 }
-BENCHMARK(BM_semaphore_sem_wait_sem_post);
 
 /*
  *    This test reports the overhead of the underlying futex wake syscall on
@@ -87,7 +87,8 @@ static void *BM_semaphore_sem_post_start_thread(void *obj) {
     return NULL;
 }
 
-static void BM_semaphore_sem_post(int iters) {
+BENCHMARK_NO_ARG(BM_semaphore_sem_post);
+void BM_semaphore_sem_post::Run(int iters) {
   StopBenchmarkTiming();
 
   sem_t semaphore;
@@ -100,9 +101,6 @@ static void BM_semaphore_sem_post(int iters) {
   pthread_attr_setschedparam(&attr, &param);
   pthread_attr_setschedpolicy(&attr, SCHED_OTHER);
   pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-#ifdef PTHREAD_SET_INHERIT_SCHED
-  pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
-#endif
   pthread_t pthread;
   pthread_create(&pthread, &attr, BM_semaphore_sem_post_start_thread, &semaphore);
   pthread_attr_destroy(&attr);
@@ -143,99 +141,3 @@ static void BM_semaphore_sem_post(int iters) {
     sched_yield();
   } while (!BM_semaphore_sem_post_running);
 }
-BENCHMARK(BM_semaphore_sem_post);
-
-/*
- *    This test reports the overhead of sem_post to sem_wake. A circle of
- * num_semaphore - 1 threads are run on a set of semaphores to measure the
- * activity. One can calculate the sem_wake overhead alone by:
- *
- * BM_semaphore_sem_post_sem_wait - BM_semaphore_sem_post - BM_time_clock_gettime
- *
- * Differences will result if there are more threads than active processors,
- * there will be delay induced when scheduling the processes. This cost is
- * measured by trying different values of num_semaphore. The governor selected
- * will have a major impact on the results for a large number of threads.
- *
- *     To reduce the chances for threads racing ahead and not triggering the
- * futex, for example the background threads finish their job before the
- * sem_wait is hit in the main thread, the background threads will run at
- * batch priority and the main thread at fifo priority. This should generally
- * guarantee the main thread completes its task of priming itself with the
- * sem_wait before the other threads can start. In practice without the
- * sched mechanics here, this works on Android configured kernels, this is
- * insurance for wacky(tm) sched configurations.
- */
-static void *BM_semaphore_sem_post_sem_wait_start_thread(void *obj) {
-  sem_t *semaphore = reinterpret_cast<sem_t *>(obj);
-
-  while ((BM_semaphore_sem_post_running > 0) && !sem_wait(semaphore)) {
-    sem_post(semaphore + 1);
-  }
-  --BM_semaphore_sem_post_running;
-  return NULL;
-}
-
-static void BM_semaphore_sem_post_sem_wait_num(int iters, int num_semaphore) {
-  StopBenchmarkTiming();
-
-  sem_t semaphore[num_semaphore];
-
-  for (int i = 0; i < num_semaphore; ++i) {
-    sem_init(semaphore + i, 0, 0);
-  }
-
-  pthread_attr_t attr;
-  pthread_attr_init(&attr);
-  BM_semaphore_sem_post_running = 1;
-  struct sched_param param = { 0, };
-  pthread_attr_setschedparam(&attr, &param);
-  pthread_attr_setschedpolicy(&attr, SCHED_BATCH);
-  pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED);
-#ifdef PTHREAD_SET_INHERIT_SCHED
-  pthread_attr_setinheritsched(&attr, PTHREAD_EXPLICIT_SCHED);
-#endif
-  for (int i = 0; i < (num_semaphore - 1); ++i) {
-    pthread_t pthread;
-    pthread_create(&pthread, &attr, BM_semaphore_sem_post_sem_wait_start_thread, semaphore + i);
-  }
-  pthread_attr_destroy(&attr);
-  sched_yield();
-
-  param.sched_priority = 1;
-  sched_setscheduler((pid_t)0, SCHED_FIFO, &param);
-
-  StartBenchmarkTiming();
-
-  for (int i = 0; i < iters; i += num_semaphore) {
-    sem_post(semaphore);
-    sem_wait(semaphore + num_semaphore - 1);
-  }
-
-  StopBenchmarkTiming();
-
-  param.sched_priority = 0;
-  sched_setscheduler((pid_t)0, SCHED_OTHER, &param);
-
-  if (BM_semaphore_sem_post_running > 0) {
-    BM_semaphore_sem_post_running = 0;
-  }
-  for (int i = 0;
-       (i < (10 * num_semaphore)) && (BM_semaphore_sem_post_running > (1 - num_semaphore));
-       ++i) {
-    for (int j = 0; j < (num_semaphore - 1); ++j) {
-      sem_post(semaphore + j);
-    }
-    sched_yield();
-  }
-}
-
-static void BM_semaphore_sem_post_sem_wait_low(int iters) {
-    BM_semaphore_sem_post_sem_wait_num(iters, 2);
-}
-BENCHMARK(BM_semaphore_sem_post_sem_wait_low);
-
-static void BM_semaphore_sem_post_sem_wait_high(int iters) {
-    BM_semaphore_sem_post_sem_wait_num(iters, 100);
-}
-BENCHMARK(BM_semaphore_sem_post_sem_wait_high);