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, 27 insertions, 23 deletions

diff --git a/benchmarks/stdio_benchmark.cpp b/benchmarks/stdio_benchmark.cpp
index 5658a506e..342e56154 100644
--- a/benchmarks/stdio_benchmark.cpp
+++ b/benchmarks/stdio_benchmark.cpp
@@ -14,11 +14,11 @@
  * limitations under the License.
  */
 
-#include "benchmark.h"
-
 #include <stdio.h>
 #include <stdio_ext.h>
 
+#include <benchmark/Benchmark.h>
+
 #define KB 1024
 #define MB 1024*KB
 
@@ -27,12 +27,12 @@
     Arg(1*KB)->Arg(4*KB)->Arg(8*KB)->Arg(16*KB)->Arg(64*KB)
 
 template <typename Fn>
-static void ReadWriteTest(int iters, int chunk_size, Fn f, bool buffered) {
-  StopBenchmarkTiming();
+void ReadWriteTest(::testing::Benchmark* benchmark, int iters, int chunk_size, Fn f, bool buffered) {
+  benchmark->StopBenchmarkTiming();
   FILE* fp = fopen("/dev/zero", "rw");
   __fsetlocking(fp, FSETLOCKING_BYCALLER);
   char* buf = new char[chunk_size];
-  StartBenchmarkTiming();
+  benchmark->StartBenchmarkTiming();
 
   if (!buffered) {
     setvbuf(fp, 0, _IONBF, 0);
@@ -42,31 +42,31 @@ static void ReadWriteTest(int iters, int chunk_size, Fn f, bool buffered) {
     f(buf, chunk_size, 1, fp);
   }
 
-  StopBenchmarkTiming();
-  SetBenchmarkBytesProcessed(int64_t(iters) * int64_t(chunk_size));
+  benchmark->StopBenchmarkTiming();
+  benchmark->SetBenchmarkBytesProcessed(int64_t(iters) * int64_t(chunk_size));
   delete[] buf;
   fclose(fp);
 }
 
-static void BM_stdio_fread(int iters, int chunk_size) {
-  ReadWriteTest(iters, chunk_size, fread, true);
+BENCHMARK_WITH_ARG(BM_stdio_fread, int)->AT_COMMON_SIZES;
+void BM_stdio_fread::Run(int iters, int chunk_size) {
+  ReadWriteTest(this, iters, chunk_size, fread, true);
 }
-BENCHMARK(BM_stdio_fread)->AT_COMMON_SIZES;
 
-static void BM_stdio_fwrite(int iters, int chunk_size) {
-  ReadWriteTest(iters, chunk_size, fwrite, true);
+BENCHMARK_WITH_ARG(BM_stdio_fwrite, int)->AT_COMMON_SIZES;
+void BM_stdio_fwrite::Run(int iters, int chunk_size) {
+  ReadWriteTest(this, iters, chunk_size, fwrite, true);
 }
-BENCHMARK(BM_stdio_fwrite)->AT_COMMON_SIZES;
 
-static void BM_stdio_fread_unbuffered(int iters, int chunk_size) {
-  ReadWriteTest(iters, chunk_size, fread, false);
+BENCHMARK_WITH_ARG(BM_stdio_fread_unbuffered, int)->AT_COMMON_SIZES;
+void BM_stdio_fread_unbuffered::Run(int iters, int chunk_size) {
+  ReadWriteTest(this, iters, chunk_size, fread, false);
 }
-BENCHMARK(BM_stdio_fread_unbuffered)->AT_COMMON_SIZES;
 
-static void BM_stdio_fwrite_unbuffered(int iters, int chunk_size) {
-  ReadWriteTest(iters, chunk_size, fwrite, false);
+BENCHMARK_WITH_ARG(BM_stdio_fwrite_unbuffered, int)->AT_COMMON_SIZES;
+void BM_stdio_fwrite_unbuffered::Run(int iters, int chunk_size) {
+  ReadWriteTest(this, iters, chunk_size, fwrite, false);
 }
-BENCHMARK(BM_stdio_fwrite_unbuffered)->AT_COMMON_SIZES;
 
 static void FopenFgetsFclose(int iters, bool no_locking) {
   char buf[1024];
@@ -78,12 +78,16 @@ static void FopenFgetsFclose(int iters, bool no_locking) {
   }
 }
 
-static void BM_stdio_fopen_fgets_fclose_locking(int iters) {
+BENCHMARK_NO_ARG(BM_stdio_fopen_fgets_fclose_locking);
+void BM_stdio_fopen_fgets_fclose_locking::Run(int iters) {
+  StartBenchmarkTiming();
   FopenFgetsFclose(iters, false);
+  StopBenchmarkTiming();
 }
-BENCHMARK(BM_stdio_fopen_fgets_fclose_locking);
 
-static void BM_stdio_fopen_fgets_fclose_no_locking(int iters) {
+BENCHMARK_NO_ARG(BM_stdio_fopen_fgets_fclose_no_locking);
+void BM_stdio_fopen_fgets_fclose_no_locking::Run(int iters) {
+  StartBenchmarkTiming();
   FopenFgetsFclose(iters, true);
+  StopBenchmarkTiming();
 }
-BENCHMARK(BM_stdio_fopen_fgets_fclose_no_locking);