/*
//@HEADER
// ************************************************************************
//
//                        Kokkos v. 2.0
//              Copyright (2014) Sandia Corporation
//
// Under the terms of Contract DE-AC04-94AL85000 with Sandia Corporation,
// the U.S. Government retains certain rights in this software.
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// modification, are permitted provided that the following conditions are
// met:
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// 1. Redistributions of source code must retain the above copyright
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//
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// this software without specific prior written permission.
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// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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*/

#include "Kokkos_Core.hpp"
#include <cstdio>
#include <cstdlib>
#include <cmath>

#include <sys/time.h>

#define HLINE "-------------------------------------------------------------\n"

#if defined(KOKKOS_ENABLE_CUDA)
typedef Kokkos::View<int64_t*, Kokkos::CudaSpace>::HostMirror GUPSHostArray;
typedef Kokkos::View<int64_t*, Kokkos::CudaSpace> GUPSDeviceArray;
#else
typedef Kokkos::View<int64_t*, Kokkos::HostSpace>::HostMirror GUPSHostArray;
typedef Kokkos::View<int64_t*, Kokkos::HostSpace> GUPSDeviceArray;
#endif

typedef int GUPSIndex;

double now() {
	struct timeval now;
	gettimeofday(&now, NULL);

	return (double) now.tv_sec + ((double) now.tv_usec * 1.0e-6);
}

void randomize_indices(GUPSHostArray& indices, GUPSDeviceArray& dev_indices, const int64_t dataCount) {
	for( GUPSIndex i = 0; i < indices.extent(0); ++i ) {
		indices[i] = lrand48() % dataCount;
	}

	Kokkos::deep_copy(dev_indices, indices);
}

void run_gups(GUPSDeviceArray& indices, GUPSDeviceArray& data, const int64_t datum,
	const bool performAtomics) {

	if( performAtomics ) {
		Kokkos::parallel_for("bench-gups-atomic", indices.extent(0), KOKKOS_LAMBDA(const GUPSIndex i) {
			Kokkos::atomic_fetch_xor( &data[indices[i]], datum );
		});
	} else {
		Kokkos::parallel_for("bench-gups-non-atomic", indices.extent(0), KOKKOS_LAMBDA(const GUPSIndex i) {
			data[indices[i]] ^= datum;
		});
	}

	Kokkos::fence();
}

int run_benchmark(const GUPSIndex indicesCount, const GUPSIndex dataCount, const int repeats,
	const bool useAtomics) {

	printf("Reports fastest timing per kernel\n");
	printf("Creating Views...\n");

	printf("Memory Sizes:\n");
	printf("- Elements:      %15" PRIu64 " (%12.4f MB)\n", static_cast<uint64_t>(dataCount),
		1.0e-6 * ((double) dataCount * (double) sizeof(int64_t)));
	printf("- Indices:       %15" PRIu64 " (%12.4f MB)\n", static_cast<uint64_t>(indicesCount),
		1.0e-6 * ((double) indicesCount * (double) sizeof(int64_t)));
	printf(" - Atomics:      %15s\n", (useAtomics ? "Yes" : "No") );
	printf("Benchmark kernels will be performed for %d iterations.\n", repeats);

	printf(HLINE);

	GUPSDeviceArray dev_indices("indices", indicesCount);
	GUPSDeviceArray dev_data("data", dataCount);
	int64_t datum = -1;

	GUPSHostArray indices = Kokkos::create_mirror_view(dev_indices);
	GUPSHostArray data    = Kokkos::create_mirror_view(dev_data);

	double gupsTime  = 0.0;

	printf("Initializing Views...\n");

#if defined(KOKKOS_HAVE_OPENMP)
	Kokkos::parallel_for("init-data", Kokkos::RangePolicy<Kokkos::OpenMP>(0, dataCount),
#else
	Kokkos::parallel_for("init-data", Kokkos::RangePolicy<Kokkos::Serial>(0, dataCount),
#endif
		KOKKOS_LAMBDA(const int i) {

		data[i] = 10101010101;
	});

#if defined(KOKKOS_HAVE_OPENMP)
	Kokkos::parallel_for("init-indices", Kokkos::RangePolicy<Kokkos::OpenMP>(0, indicesCount),
#else
	Kokkos::parallel_for("init-indices", Kokkos::RangePolicy<Kokkos::Serial>(0, indicesCount),
#endif
		KOKKOS_LAMBDA(const int i) {

		indices[i] = 0;
	});

	Kokkos::deep_copy(dev_data, data);
	Kokkos::deep_copy(dev_indices, indices);
	double start;

	printf("Starting benchmarking...\n");

	for( GUPSIndex k = 0; k < repeats; ++k ) {
		randomize_indices(indices, dev_indices, data.extent(0));

		start = now();
		run_gups(dev_indices, dev_data, datum, useAtomics);
		gupsTime += now() - start;
	}

	Kokkos::deep_copy(indices, dev_indices);
	Kokkos::deep_copy(data, dev_data);

	printf(HLINE);
	printf("GUP/s Random:      %18.6f\n",
		(1.0e-9 * ((double) repeats) * (double) dev_indices.extent(0)) / gupsTime);
	printf(HLINE);

	return 0;
}

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

	printf(HLINE);
	printf("Kokkos GUPS Benchmark\n");
	printf(HLINE);

	srand48(1010101);

	Kokkos::initialize(argc, argv);

	int64_t indices = 8192;
	int64_t data    = 33554432;
	int64_t repeats = 10;
	bool useAtomics = false;

	for( int i = 1; i < argc; ++i ) {
		if( strcmp( argv[i], "--indices" ) == 0 ) {
			indices = std::atoll(argv[i+1]);
			++i;
		} else if( strcmp( argv[i], "--data" ) == 0 ) {
			data = std::atoll(argv[i+1]);
			++i;
		} else if( strcmp( argv[i], "--repeats" ) == 0 ) {
			repeats = std::atoll(argv[i+1]);
			++i;
		} else if( strcmp( argv[i], "--atomics" ) == 0 ) {
			useAtomics = true;
		}
	}

	const int rc = run_benchmark(indices, data, repeats, useAtomics);

	Kokkos::finalize();

	return rc;
}