BabelStream/HCStream.cpp
2017-03-24 15:19:48 +01:00

286 lines
9.0 KiB
C++

// Copyright (c) 2015-16 Peter Steinbach, MPI CBG Scientific Computing Facility
//
// For full license terms please see the LICENSE file distributed with this
// source code
#include <codecvt>
#include <vector>
#include <locale>
#include <numeric>
#include "HCStream.h"
#define TBSIZE 1024
std::string getDeviceName(const hc::accelerator& _acc)
{
std::wstring_convert<std::codecvt_utf8<wchar_t>, wchar_t> converter;
std::string value = converter.to_bytes(_acc.get_description());
return value;
}
void listDevices(void)
{
// Get number of devices
std::vector<hc::accelerator> accs = hc::accelerator::get_all();
// Print device names
if (accs.empty())
{
std::cerr << "No devices found." << std::endl;
}
else
{
std::cout << std::endl;
std::cout << "Devices:" << std::endl;
for (int i = 0; i < accs.size(); i++)
{
std::cout << i << ": " << getDeviceName(accs[i]) << std::endl;
}
std::cout << std::endl;
}
}
template <class T>
HCStream<T>::HCStream(const unsigned int ARRAY_SIZE, const int device_index):
array_size(ARRAY_SIZE),
d_a(ARRAY_SIZE),
d_b(ARRAY_SIZE),
d_c(ARRAY_SIZE)
{
// The array size must be divisible by TBSIZE for kernel launches
if (ARRAY_SIZE % TBSIZE != 0)
{
std::stringstream ss;
ss << "Array size must be a multiple of " << TBSIZE;
throw std::runtime_error(ss.str());
}
// // Set device
std::vector<hc::accelerator> accs = hc::accelerator::get_all();
auto current = accs[device_index];
hc::accelerator::set_default(current.get_device_path());
std::cout << "Using HC device " << getDeviceName(current) << std::endl;
}
template <class T>
HCStream<T>::~HCStream()
{
}
template <class T>
void HCStream<T>::init_arrays(T _a, T _b, T _c)
{
hc::array_view<T,1> view_a(this->d_a);
hc::array_view<T,1> view_b(this->d_b);
hc::array_view<T,1> view_c(this->d_c);
hc::completion_future future_a= hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_a[i] = _a;
});
hc::completion_future future_b= hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_b[i] = _b;
});
hc::completion_future future_c= hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_c[i] = _c;
});
try{
future_a.wait();
future_b.wait();
future_c.wait();
}
catch(std::exception& e){
std::cout << __FILE__ << ":" << __LINE__ << "\t future_{a,b,c} " << e.what() << std::endl;
throw;
}
}
template <class T>
void HCStream<T>::read_arrays(std::vector<T>& a, std::vector<T>& b, std::vector<T>& c)
{
hc::copy(d_a,a.begin());
hc::copy(d_b,b.begin());
hc::copy(d_c,c.begin());
}
template <class T>
void HCStream<T>::copy()
{
hc::array_view<T,1> view_a = this->d_a;
hc::array_view<T,1> view_c = this->d_c;
try{
hc::completion_future future_kernel = hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> index) [[hc]] {
view_c[index] = view_a[index];
});
future_kernel.wait();
}
catch(std::exception& e){
std::cerr << __FILE__ << ":" << __LINE__ << "\t" << e.what() << std::endl;
throw;
}
}
template <class T>
void HCStream<T>::mul()
{
const T scalar = 0.3;
hc::array_view<T,1> view_b = this->d_b;
hc::array_view<T,1> view_c = this->d_c;
try{
hc::completion_future future_kernel = hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_b[i] = scalar*view_c[i];
});
future_kernel.wait();
}
catch(std::exception& e){
std::cerr << __FILE__ << ":" << __LINE__ << "\t" << e.what() << std::endl;
throw;
}
}
template <class T>
void HCStream<T>::add()
{
hc::array_view<T,1> view_a(this->d_a);
hc::array_view<T,1> view_b(this->d_b);
hc::array_view<T,1> view_c(this->d_c);
try{
hc::completion_future future_kernel = hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_c[i] = view_a[i]+view_b[i];
});
future_kernel.wait();
}
catch(std::exception& e){
std::cerr << __FILE__ << ":" << __LINE__ << "\t" << e.what() << std::endl;
throw;
}
}
template <class T>
void HCStream<T>::triad()
{
const T scalar = 0.3;
hc::array_view<T,1> view_a(this->d_a);
hc::array_view<T,1> view_b(this->d_b);
hc::array_view<T,1> view_c(this->d_c);
try{
hc::completion_future future_kernel = hc::parallel_for_each(hc::extent<1>(array_size)
, [=](hc::index<1> i) [[hc]] {
view_a[i] = view_b[i] + scalar*view_c[i];
});
future_kernel.wait();
}
catch(std::exception& e){
std::cerr << __FILE__ << ":" << __LINE__ << "\t" << e.what() << std::endl;
throw;
}
}
template <class T>
T HCStream<T>::dot()
{
//implementation adapted from
//https://ampbook.codeplex.com/SourceControl/latest
// ->Samples/CaseStudies/Reduction
// ->CascadingReduction.h
hc::array_view<T,1> view_a(this->d_a);
hc::array_view<T,1> view_b(this->d_b);
auto ex = view_a.get_extent();
hc::tiled_extent<1> tiled_ex = ex.tile(TBSIZE);
const size_t n_tiles = 64;
const size_t n_elements = array_size;
// hc::array<T,1> d_product(array_size);
// hc::array_view<T,1> view_p(d_product) ;
hc::array<T, 1> partial(n_tiles*TBSIZE);
hc::array_view<T,1> partialv(partial) ;
hc::completion_future dot_kernel = hc::parallel_for_each(tiled_ex,
[=](hc::tiled_index<1> tidx) [[hc]] {
std::size_t tid = tidx.local[0];//index in the tile
tile_static T tileData[TBSIZE];
std::size_t i = (tidx.tile[0] * 2 * TBSIZE) + tid;
std::size_t stride = TBSIZE * 2 * n_tiles;
// Load and add many elements, rather than just two
T sum = 0;
do
{
T near = view_a[i]*view_b[i];
T far = view_a[i+TBSIZE]*view_b[i+TBSIZE];
sum += (far + near);
i += stride;
}
while (i < n_elements);
tileData[tid] = sum;
tidx.barrier.wait();
// Reduce values for data on this tile
for (stride = (TBSIZE / 2); stride > 0; stride >>= 1)
{
// Remember that this is a branch within a loop and all threads will have to execute
// this but only threads with a tid < stride will do useful work.
if (tid < stride)
tileData[tid] += tileData[tid + stride];
tidx.barrier.wait_with_tile_static_memory_fence();
}
// Write the result for this tile back to global memory
if (tid == 0)
partialv[tidx.tile[0]] = tileData[tid];
});
try{
dot_kernel.wait();
}
catch(std::exception& e){
std::cerr << __FILE__ << ":" << __LINE__ << "\t" << e.what() << std::endl;
throw;
}
std::vector<T> h_partial(n_tiles);
hc::copy(partial, h_partial.begin());
T result = std::accumulate(h_partial.begin(), h_partial.end(), 0.);
return result;
}
template class HCStream<float>;
template class HCStream<double>;