ParallelMapBenchmark.cpp File Reference

#include <algorithm>
#include <atomic>
#include <thread>
#include <vector>
#include <folly/Benchmark.h>
#include <folly/gen/Base.h>
#include <folly/gen/ParallelMap.h>
#include <folly/portability/Unistd.h>

Go to the source code of this file.

Functions
	DEFINE_int32 (threads, std::max(1,(int32_t) sysconf(_SC_NPROCESSORS_CONF)/2),"Num threads.")
size_t	fib (int n)
	BENCHMARK (FibSumMap, n)
	BENCHMARK_RELATIVE (FibSumPmap, n)
	BENCHMARK_RELATIVE (FibSumThreads, n)
int	main (int argc, char *argv[])

Variables
constexpr int	kFib = 35

Function Documentation

BENCHMARK	(	FibSumMap	,
		n
	)

Definition at line 39 of file ParallelMapBenchmark.cpp.

References folly::doNotOptimizeAway(), fib(), folly::gen::map(), folly::gen::seq(), and folly::gen::sum.

                        {
  auto result = seq(1, (int)n) | map([](int) { return fib(kFib); }) | sum;
  folly::doNotOptimizeAway(result);
}

BENCHMARK_RELATIVE	(	FibSumPmap	,
		n
	)

Definition at line 44 of file ParallelMapBenchmark.cpp.

References folly::doNotOptimizeAway(), fib(), kNumThreads, folly::gen::pmap(), folly::gen::seq(), and folly::gen::sum.

                                  {
  // Schedule more work: enough so that each worker thread does the
  // same amount as one FibSumMap.
  const size_t kNumThreads = FLAGS_threads;
  // clang-format off
  auto result =
    seq(1, (int)(n * kNumThreads))
    | pmap([](int) { return fib(kFib); }, kNumThreads)
    | sum;
  // clang-format on
  folly::doNotOptimizeAway(result);
}

BENCHMARK_RELATIVE	(	FibSumThreads	,
		n
	)

Definition at line 57 of file ParallelMapBenchmark.cpp.

References folly::doNotOptimizeAway(), fib(), i, kNumThreads, folly::gen::map(), folly::gen::seq(), and folly::gen::sum.

                                     {
  // Schedule kNumThreads to execute the same code as FibSumMap.
  const size_t kNumThreads = FLAGS_threads;
  std::vector<std::thread> workers;
  workers.reserve(kNumThreads);
  auto fn = [n] {
    auto result = seq(1, (int)n) | map([](int) { return fib(kFib); }) | sum;
    folly::doNotOptimizeAway(result);
  };
  for (size_t i = 0; i < kNumThreads; i++) {
    workers.push_back(std::thread(fn));
  }
  for (auto& w : workers) {
    w.join();
  }
}

DEFINE_int32	(	threads	,
		std::max(1,(int32_t) sysconf(_SC_NPROCESSORS_CONF)/2)	,
		"Num threads."
	)

size_t fib

(

int

n

)

Definition at line 35 of file ParallelMapBenchmark.cpp.

Referenced by BENCHMARK(), and BENCHMARK_RELATIVE().

                  {
  return n <= 1 ? 1 : fib(n - 1) * fib(n - 2);
}

int main	(	int	argc,
		char *	argv[]
	)

Definition at line 88 of file ParallelMapBenchmark.cpp.

References folly::runBenchmarks().

                                 {
  gflags::ParseCommandLineFlags(&argc, &argv, true);
  folly::runBenchmarks();
  return 0;
}

Variable Documentation

constexpr int kFib = 35

Definition at line 34 of file ParallelMapBenchmark.cpp.