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hpc-2022-g3/atax/atax.cu
2022-12-01 01:12:07 +01:00

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#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <math.h>
#include <iostream>
/* Include polybench common header. */
#include "polybench.hu"
/* Include benchmark-specific header. */
/* Default data type is double, default size is 4000. */
#include "atax.hu"
// Workaround for the editor not finding M_PI
// It is exclusive to the GNU C compiler
// https://www.gnu.org/software/libc/manual/html_node/Mathematical-Constants.html
#ifndef M_PI
#define M_PI 3.141
#endif
// Default if CUDA_NTHREADS is not set
#ifndef CUDA_NTHREADS
#define CUDA_NTHREADS 128
#endif
// Enable syntax highlighting for the CUDA mode
// TODO: Remove this, as it will be set by .bench.sh
#define HPC_USE_CUDA
// Enable syntax highlighting for the stride mode
// TODO: Remove this, as it will be set by .bench.sh
#define HPC_USE_STRIDE
// Create macro for debug logging
#define debug(txt) std::cerr << txt << std::endl
/**
* Initialize the arrays to be used in the computation:
*
* - `X` is filled with multiples of `M_PI`;
* - `Y` is zeroed;
* - `A` is filled with sample data.
*
* To be called on the CPU (uses the `__host__` qualifier).
*/
#ifndef HPC_USE_CUDA
__host__ static void init_array(DATA_TYPE** A, DATA_TYPE* X, DATA_TYPE* Y)
{
/* X = [ 3.14, 6.28, 9.42, ... ] */
for (unsigned int y = 0; y < NY; y++)
{
X[y] = y * M_PI;
}
/* Y = [ 0.00, 0.00, 0.00, ... ] */
for (unsigned int x = 0; x < NY; x++)
{
Y[x] = 0;
}
/*
* A = [
* [ 0, 0, 0, 0, ... ],
* [ 1 / NX, 2 / NX, 3 / NX, 4 / NX, ... ],
* [ 2 / NX, 4 / NX, 6 / NX, 8 / NX, ... ],
* [ 3 / NX, 6 / NX, 9 / NX, 12 / NX, ... ],
* ...
* ]
*/
for (unsigned int x = 0; x < NX; x++)
{
for (unsigned int y = 0; y < NY; y++)
{
A[x][y] = (DATA_TYPE)(x * (y + 1)) / NX;
}
}
}
#endif
/**
* Initialize the `X` array.
*
* Runs on the device.
*/
#ifdef HPC_USE_CUDA
__device__ static void init_array_cuda_x(DATA_TYPE* X, unsigned int threads)
{
// Find how many iterations should be performed by each thread
unsigned int perThread = NY / threads;
// Find the index of the current thread, even if threads span multiple blocks
int blockThreadIdx = blockIdx.x * blockDim.x + threadIdx.x;
// Have each thread perform the previously determined number of iterations
for(int stride = 0; stride < perThread; stride++) {
// Find the index of the current iteration
// This is equal to `y` of the init_array function
int iterationIdx = blockThreadIdx * stride;
// Prevent the thread from accessing unallocated memory
if(iterationIdx < NY) {
// Set the array element
X[iterationIdx] = iterationIdx * M_PI;
}
}
}
#endif
/**
* Initialize the `Y` array.
*
* Runs on the device.
*/
#ifdef HPC_USE_CUDA
__device__ static void init_array_cuda_y(DATA_TYPE* Y, unsigned int threads)
{
// Find how many iterations should be performed by each thread
unsigned int perThread = NX / threads;
// Find the index of the current thread, even if threads span multiple blocks
int blockThreadIdx = blockIdx.x * blockDim.x + threadIdx.x;
// Have each thread perform the previously determined number of iterations
for(int stride = 0; stride < perThread; stride++) {
// Find the index of the current iteration
// This is equal to `y` of the init_array function
int iterationIdx = blockThreadIdx * stride;
// Prevent the thread from accessing unallocated memory
if(iterationIdx < NX) {
// Set the array element
Y[iterationIdx] = 0;
}
}
}
#endif
/**
* Initialize the `A` array.
*
* Runs on the device.
*/
#ifdef HPC_USE_CUDA
__device__ static void init_array_cuda_a(DATA_TYPE* A, unsigned int threads)
{
// Find how many elements should be written in total
unsigned int elements = NX * NY;
// Find how many iterations should be performed by each thread
unsigned int perThread = elements / threads;
// Find the index of the current thread, even if threads span multiple blocks
int blockThreadIdx = blockIdx.x * blockDim.x + threadIdx.x;
/* TODO */
}
#endif
/**
* Initialize the arrays to be used in the computation:
*
* - `X` is filled with multiples of `M_PI`;
* - `Y` is zeroed;
* - `A` is filled with sample data.
*
* Beware that `A` here is a simple array, it is not a matrix, so elements are accessed via [y * NX + x] (I think?).
*
* It is called by the host, runs on the device, and calls the other init_arrays on the device.
*/
#ifdef HPC_USE_CUDA
__global__ static void init_array_cuda(DATA_TYPE* A, DATA_TYPE* X, DATA_TYPE* Y)
{
unsigned int threads = gridDim.x * blockDim.x;
init_array_cuda_x(X, threads);
init_array_cuda_y(Y, threads);
init_array_cuda_a(A, threads);
}
#endif
/**
* Print the given array.
*
* Cannot be parallelized, as the elements of the array should be
*
* To be called on the CPU (uses the `__host__` qualifier).
*/
__host__ static void print_array(DATA_TYPE* Y)
{
for (unsigned int x = 0; x < NX; x++)
{
fprintf(stderr, DATA_PRINTF_MODIFIER, Y[x]);
}
fprintf(stderr, "\n");
}
/**
* Compute ATAX :
* - A is the input matrix
* - X is an input vector
* - Y is the result vector
*
* In particular:
* ```
* A * (A * X) = Y
* ```
* Wait, there's no transposition here?!?
*
* Parallelizing this is the goal of the assignment.
*
* Currently to be called on the CPU (uses the `__host__` qualifier), but we may probably want to change that soon.
*/
__host__ static void kernel_atax(DATA_TYPE** A, DATA_TYPE* X, DATA_TYPE* Y)
{
for (unsigned int x = 0; x < NX; x++)
{
DATA_TYPE tmp = 0;
for (unsigned int y = 0; y < NY; y++)
{
tmp += A[x][y] * X[y];
}
for (unsigned int y = 0; y < NY; y++)
{
Y[y] += A[x][y] * tmp;
}
}
}
/**
* The main function of the benchmark, which sets up tooling to measure the time spent computing `kernel_atax`.
*
* We should probably avoid editing this.
*/
__host__ int main(int argc, char** argv)
{
debug("Starting main...");
#ifndef HPC_USE_CUDA
debug("[Mode] Host-only");
debug("[Pointers] Allocating...");
// A[NX][NY]
DATA_TYPE** A = new DATA_TYPE*[NX] {};
for(unsigned int x = 0; x < NX; x++)
{
A[x] = new DATA_TYPE[NY] {};
}
// X[NY]
DATA_TYPE* X = new DATA_TYPE[NY] {};
// Y[NX]
DATA_TYPE* Y = new DATA_TYPE[NX] {};
debug("[Pointers] Allocated!");
#ifdef HPC_INCLUDE_INIT
debug("[Benchmark] Starting...");
polybench_start_instruments;
#endif
debug("[Init] Initializing...");
init_array(A, X, Y);
debug("[Init] Initialized!");
#ifndef HPC_INCLUDE_INIT
debug("[Benchmark] Starting...");
polybench_start_instruments;
#endif
debug("[Kernel] Running...");
kernel_atax(A, X, Y);
debug("[Kernel] Completed!");
debug("[Benchmark] Stopping...");
polybench_stop_instruments;
polybench_print_instruments;
debug("[Benchmark] Complete!");
debug("[Verify] Printing...")
polybench_prevent_dce(
print_array(Y)
);
debug("[Verify] Done!")
#else
debug("[Mode] Host-and-device, CUDA");
debug("[Pointers] Allocating...");
DATA_TYPE* A;
DATA_TYPE* X;
DATA_TYPE* Y;
debug("[CUDA] Allocating A...");
if(cudaMalloc((void**)&A, sizeof(DATA_TYPE) * NX * NY))
{
debug("[CUDA] Could not allocate A!");
return 1;
}
debug("[CUDA] Allocated A!");
debug("[CUDA] Allocating X...");
if(cudaMalloc((void**)&X, sizeof(DATA_TYPE) * NY))
{
debug("[CUDA] Could not allocate X!");
return 1;
}
debug("[CUDA] Allocated X!");
debug("[CUDA] Allocating Y...");
if(cudaMalloc((void**)&Y, sizeof(DATA_TYPE) * NX))
{
debug("[CUDA] Could not allocate Y!");
return 1;
}
debug("[CUDA] Allocated Y!");
#ifdef POLYBENCH_INCLUDE_INIT
debug("[Benchmark] Starting...");
polybench_start_instruments;
#endif
debug("[Init] Initializing...");
init_array_cuda<<<32, 32>>>((double*) A, (double*) X, (double*) Y);
if(cudaGetLastError())
{
debug("[Init] Failed to execute kernel!");
return 1;
}
debug("[Init] Initialized!");
#ifndef POLYBENCH_INCLUDE_INIT
debug("[Benchmark] Starting...");
polybench_start_instruments;
#endif
// kernel_atax_cuda<<<1, 1>>>();
polybench_stop_instruments;
polybench_print_instruments;
// Y = cudaMemcpy();
/*
polybench_prevent_dce(
print_array(Y)
);
*/
#endif
return 0;
}