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Add an OpenCL dot kernel

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We have to name the kernel stream_dot (for example) because the
"dot" kernel already exists.
This commit is contained in:
Tom Deakin 2016-10-14 17:07:55 +01:00
parent 8a100f07b4
commit 2085cacea0
2 changed files with 50 additions and 0 deletions
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41
OCLStream.cpp
View File

@ -50,6 +50,29 @@ std::string kernels{R"CLC(
a[i] = b[i] + scalar * c[i];
}
kernel void stream_dot(
global const TYPE * restrict a,
global const TYPE * restrict b,
global TYPE * restrict sum,
local TYPE * restrict wg_sum)
{
const size_t i = get_global_id(0);
const size_t local_i = get_local_id(0);
wg_sum[local_i] = a[i] * b[i];
for (int offset = get_local_size(0) / 2; offset > 0; offset /= 2)
{
barrier(CLK_LOCAL_MEM_FENCE);
if (local_i < offset)
{
wg_sum[local_i] += wg_sum[local_i+offset];
}
}
if (local_i == 0)
sum[get_group_id(0)] = wg_sum[local_i];
}
)CLC"};
@ -99,6 +122,7 @@ OCLStream<T>::OCLStream(const unsigned int ARRAY_SIZE, const int device_index)
mul_kernel = new cl::KernelFunctor<cl::Buffer, cl::Buffer>(program, "mul");
add_kernel = new cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer>(program, "add");
triad_kernel = new cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer>(program, "triad");
dot_kernel = new cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer, cl::LocalSpaceArg>(program, "stream_dot");
array_size = ARRAY_SIZE;
@ -114,6 +138,7 @@ OCLStream<T>::OCLStream(const unsigned int ARRAY_SIZE, const int device_index)
d_a = cl::Buffer(context, CL_MEM_READ_WRITE, sizeof(T) * ARRAY_SIZE);
d_b = cl::Buffer(context, CL_MEM_READ_WRITE, sizeof(T) * ARRAY_SIZE);
d_c = cl::Buffer(context, CL_MEM_READ_WRITE, sizeof(T) * ARRAY_SIZE);
d_sum = cl::Buffer(context, CL_MEM_WRITE_ONLY, sizeof(T) * WGSIZE);
}
@ -166,6 +191,22 @@ void OCLStream<T>::triad()
queue.finish();
}
template <class T>
T OCLStream<T>::dot()
{
(*dot_kernel)(
cl::EnqueueArgs(queue, cl::NDRange(array_size), cl::NDRange(WGSIZE)),
d_a, d_b, d_sum, cl::Local(sizeof(T) * WGSIZE)
);
cl::copy(queue, d_sum, sums.begin(), sums.end());
T sum = 0.0;
for (T val : sums)
sum += val;
return sum;
}
template <class T>
void OCLStream<T>::write_arrays(const std::vector<T>& a, const std::vector<T>& b, const std::vector<T>& c)
{

9
OCLStream.h
View File

@ -20,17 +20,24 @@
#define IMPLEMENTATION_STRING "OpenCL"
// Local work-group size for dot kernel
#define WGSIZE 1024
template <class T>
class OCLStream : public Stream<T>
{
protected:
// Size of arrays
unsigned int array_size;
// Host array for partial sums for dot kernel
std::vector<T> sums;
// Device side pointers to arrays
cl::Buffer d_a;
cl::Buffer d_b;
cl::Buffer d_c;
cl::Buffer d_sum;
// OpenCL objects
cl::Device device;
@ -41,6 +48,7 @@ class OCLStream : public Stream<T>
cl::KernelFunctor<cl::Buffer, cl::Buffer> * mul_kernel;
cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer> *add_kernel;
cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer> *triad_kernel;
cl::KernelFunctor<cl::Buffer, cl::Buffer, cl::Buffer, cl::LocalSpaceArg> *dot_kernel;
public:
@ -51,6 +59,7 @@ class OCLStream : public Stream<T>
virtual void add() override;
virtual void mul() override;
virtual void triad() override;
virtual T dot() override;
virtual void write_arrays(const std::vector<T>& a, const std::vector<T>& b, const std::vector<T>& c) override;
virtual void read_arrays(std::vector<T>& a, std::vector<T>& b, std::vector<T>& c) override;