C++ CUDA：填充列主矩阵
我是CUDA的新手，我正试图将我为一个性能关键项目所做的一些繁琐的计算工作转移到GPU上。在我的电脑上，我有两个NVS 510图形卡，但我目前只试验一个 我有一些大列主矩阵（1000-5000行x 1-5m列）需要填充。到目前为止，我已经能够编写代码来填充矩阵，就像它是一个数组一样，并且对于相对较小的矩阵来说效果很好C++ CUDA：填充列主矩阵,c++,cuda,C++,Cuda,我是CUDA的新手，我正试图将我为一个性能关键项目所做的一些繁琐的计算工作转移到GPU上。在我的电脑上，我有两个NVS 510图形卡，但我目前只试验一个 我有一些大列主矩阵（1000-5000行x 1-5m列）需要填充。到目前为止，我已经能够编写代码来填充矩阵，就像它是一个数组一样，并且对于相对较小的矩阵来说效果很好 __global__ void interp_kernel(fl_type * d_matrix, fl_type* weights, [other params], int n
__global__ void interp_kernel(fl_type * d_matrix, fl_type* weights, [other params],
int n_rows, int num_cols) {
int index = blockIdx.x * blockDim.x + threadIdx.x;
int column = index / n_rows;
int row = index % n_rows;
if (row > n_sim || column > num_cols) return;
d_matrix[index] = …something(row, column,[other params]);
}
fl_type *res;
cudaMalloc((void**)&res, n_columns*n_rows*fl_size);
int block_size = 1024;
int num_blocks = (n_rows* n_columns + block_size - 1) / block_size;
std::cout << "num_blocks:" << num_blocks << std::endl;
interp_kernel << < num_blocks, block_size >> > (res,[other params], n_rows,n_columns);
int block_size2 = 32; //each block will have block_size2*block_size2 threads
dim3 num_blocks2(block_size2, block_size2);
int x_grid = (n_columns + block_size2 - 1) / block_size2;
int y_grid = (n_rows + block_size2 - 1) / block_size2;
dim3 grid_size2(x_grid, y_grid);
interp_kernel2D <<< grid_size2, num_blocks2 >>> (res,[other params], n_rows,n_columns);
int block_size2=32//每个块将具有块大小2*块大小2线程
dim3 num_blocks2（block_size2，block_size2）；
int x_grid=（n_列+块大小2-1）/块大小2；
int y_网格=（n_行+块大小2-1）/块大小2；
dim3网格尺寸2（x网格、y网格）；
interp_kernel2D>（res[其他参数]，n_行，n_列）；
#include "cuda_runtime.h"
#include "device_launch_parameters.h"
#include <stdio.h>
#include <assert.h>
#include <iostream>
#include <random>
#include <chrono>
typedef float fl_type;
typedef int pos_type;
typedef std::chrono::milliseconds ms;
//declaration of the cuda function
void cuda_interpolation_function(fl_type* interp_value_back, int result_size, fl_type * grid_values, int grid_values_size, fl_type* weights, pos_type* node_map, int total_action_number, int interp_dim, int n_sim);
fl_type iterp_cpu(fl_type* weights, pos_type* node_map, fl_type* grid_values, int& row, int& column, int& interp_dim, int& n_sim) {
int w_p = column*interp_dim;
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[node_map[w_p + inter_point] * n_sim + row];
}
return res;
}
__global__ void interp_kernel(fl_type * d_matrix, fl_type* weights, pos_type* node_map, fl_type* grid_values, int interp_dim, int n_sim, int num_cols) {
int index = blockIdx.x * blockDim.x + threadIdx.x;
int column = index / n_sim;
int row = index % n_sim;
int w_p = column*interp_dim;
if (row > n_sim || column > num_cols) return;
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[row + node_map[w_p + inter_point] * n_sim];
}
d_matrix[index] = res;
}
__global__ void interp_kernel2D(fl_type * d_matrix, fl_type* weights, pos_type* node_map, fl_type* grid_values, int interp_dim, int n_sim, int num_cols) {
int column = blockIdx.x * blockDim.x + threadIdx.x;
int row = blockIdx.y * blockDim.y + threadIdx.y;
int index = column*n_sim + row;
int w_p = column*interp_dim;
if (row > n_sim || column > num_cols) return;
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[row + node_map[w_p + inter_point] * n_sim];
}
d_matrix[index] = res;
}
void verify(fl_type *host, fl_type *device, int size) {
int count = 0;
int count_zero = 0;
for (int i = 0; i < size; i++) {
if (host[i] != device[i]) {
count++;
//std::cout <<"pos: " <<i<< " CPU:" <<h[i] << ", GPU: " << d[i] <<std::endl;
assert(host[i] == device[i]);
if (device[i] == 0.0)
count_zero++;
}
}
if (count) {
std::cout << "Non matching: " << count << "out of " << size << "(" << (float(count) / size * 100) << "%)" << std::endl;
std::cout << "Zeros returned from the device: " << count_zero <<"(" << (float(count_zero) / size * 100) << "%)" << std::endl;
}
else
std::cout << "Perfect match!" << std::endl;
}
int main() {
int fl_size = sizeof(fl_type);
int pos_size = sizeof(pos_type);
int dim = 5; // range: 2-5
int number_nodes = 5500; // range: 10.000-500.000
int max_actions = 12; // range: 6-200
int n_sim = 1000; // range: 1.000-10.000
int interp_dim = std::pow(2, dim);
int grid_values_size = n_sim*number_nodes;
std::default_random_engine generator;
std::normal_distribution<fl_type> normal_dist(0.0, 1);
std::uniform_int_distribution<> uniform_dist(0, number_nodes - 1);
double bit_allocated = 0;
fl_type * grid_values; //flattened 2d array, containing the value of the grid (n_sims x number_nodes)
grid_values = (fl_type *)malloc(grid_values_size * fl_size);
bit_allocated += grid_values_size * fl_size;
for (int i = 0; i < grid_values_size; i++)
grid_values[i] = normal_dist(generator);
pos_type * map_node2values_start; //vector that maps each node to the first column of the result matrix regarding that done
pos_type * map_node2values_how_many; //vector that stores how many action we have per node
map_node2values_start = (pos_type *)malloc(number_nodes * pos_size);
map_node2values_how_many = (pos_type *)malloc(number_nodes * pos_size);
bit_allocated += 2 * (number_nodes * pos_size);
for (int i = 0; i < number_nodes; i++) {
//each node as simply max_actions
map_node2values_start[i] = max_actions*i;
map_node2values_how_many[i] = max_actions;
}
//total number of actions, which is amount of column of the results
int total_action_number = map_node2values_start[number_nodes - 1] + map_node2values_how_many[number_nodes - 1];
//vector that keep tracks of the columnt to grab, and their weight in the interpolation
fl_type* weights;
pos_type * node_map;
weights = (fl_type *)malloc(total_action_number*interp_dim * pos_size);
bit_allocated += total_action_number * fl_size;
node_map = (pos_type *)malloc(total_action_number*interp_dim * pos_size);
bit_allocated += total_action_number * pos_size;
//filling with random numbers
for (int i = 0; i < total_action_number*interp_dim; i++) {
node_map[i] = uniform_dist(generator); // picking random column
weights[i] = 1.0 / interp_dim; // uniform weights
}
std::cout << "done filling!" << std::endl;
std::cout << bit_allocated / 8 / 1024 / 1024 << "MB allocated" << std::endl;
int result_size = n_sim*total_action_number;
fl_type *interp_value_cpu;
bit_allocated += result_size* fl_size;
interp_value_cpu = (fl_type *)malloc(result_size* fl_size);
auto start = std::chrono::steady_clock::now();
for (int row = 0; row < n_sim; row++) {
for (int column = 0; column < total_action_number; column++) {
auto zz = iterp_cpu(weights, node_map, grid_values, row, column, interp_dim, n_sim);
interp_value_cpu[column*n_sim + row] = zz;
}
}
auto elapsed_cpu = std::chrono::steady_clock::now() - start;
std::cout << "Crunching values on the CPU (serial): " << std::chrono::duration_cast<ms>(elapsed_cpu).count() / 1000.0 << "s" << std::endl;
int * pp;
cudaMalloc((void**)&pp, sizeof(int)); //initializing the device, to not affect the benchmark
fl_type *interp_value_gpu;
interp_value_gpu = (fl_type *)malloc(result_size* fl_size);
start = std::chrono::steady_clock::now();
cuda_interpolation_function(interp_value_gpu, result_size, grid_values, grid_values_size, weights, node_map, total_action_number, interp_dim, n_sim);
auto elapsed_gpu = std::chrono::steady_clock::now() - start;
std::cout << "Crunching values on the GPU: " << std::chrono::duration_cast<ms>(elapsed_gpu).count() / 1000.0 << "s" << std::endl;
float ms_cpu = std::chrono::duration_cast<ms>(elapsed_cpu).count();
float ms_gpu = std::chrono::duration_cast<ms>(elapsed_gpu).count();
int n_proc = 4;
std::cout << "Performance: " << (ms_gpu- ms_cpu / n_proc) / (ms_cpu / n_proc) * 100 << " % less time than parallel CPU!" << std::endl;
verify(interp_value_cpu, interp_value_gpu, result_size);
free(interp_value_cpu);
free(interp_value_gpu);
free(grid_values);
free(node_map);
free(weights);
}
void cuda_interpolation_function(fl_type* interp_value_gpu, int result_size, fl_type * grid_values, int grid_values_size, fl_type* weights, pos_type* node_map, int total_action_number, int interp_dim, int n_sim) {
int fl_size = sizeof(fl_type);
int pos_size = sizeof(pos_type);
auto start = std::chrono::steady_clock::now();
//device versions of the inputs
fl_type * grid_values_device;
fl_type* weights_device;
pos_type * node_map_device;
fl_type *interp_value_device;
int lenght_node_map = interp_dim*total_action_number;
std::cout << "size grid_values: " << grid_values_size <<std::endl;
std::cout << "size weights: " << lenght_node_map << std::endl;
std::cout << "size interp_value: " << result_size << std::endl;
//allocating and moving to the GPU the inputs
auto error_code=cudaMalloc((void**)&grid_values_device, grid_values_size*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of the grid_values" << std::endl;
}
error_code=cudaMemcpy(grid_values_device, grid_values, grid_values_size*fl_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of the grid_values" << std::endl;
}
error_code=cudaMalloc((void**)&weights_device, lenght_node_map*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of the weights" << std::endl;
}
error_code=cudaMemcpy(weights_device, weights, lenght_node_map*fl_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of the weights" << std::endl;
}
error_code=cudaMalloc((void**)&node_map_device, lenght_node_map*pos_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of node_map" << std::endl;
}
error_code=cudaMemcpy(node_map_device, node_map, lenght_node_map*pos_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of node_map" << std::endl;
}
error_code=cudaMalloc((void**)&interp_value_device, result_size*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of interp_value_device " << std::endl;
}
auto elapsed_moving = std::chrono::steady_clock::now() - start;
float ms_moving = std::chrono::duration_cast<ms>(elapsed_moving).count();
cudaDeviceSynchronize();
//1d
int block_size = 1024;
int num_blocks = (result_size + block_size - 1) / block_size;
std::cout << "num_blocks:" << num_blocks << std::endl;
interp_kernel << < num_blocks, block_size >> > (interp_value_device, weights_device, node_map_device, grid_values_device, interp_dim, n_sim, total_action_number);
//2d
//int block_size2 = 32; //each block will have block_size2*block_size2 threads
//dim3 num_blocks2(block_size2, block_size2);
//int x_grid = (total_action_number + block_size2 - 1) / block_size2;
//int y_grid = (n_sim + block_size2 - 1) / block_size2;
//dim3 grid_size2(x_grid, y_grid);
//std::cout <<"grid:"<< x_grid<<" x "<< y_grid<<std::endl;
//interp_kernel2D <<< grid_size2, num_blocks2 >>> (interp_value_device, weights_device, node_map_device, grid_values_device, interp_dim, n_sim, total_action_number);
cudaDeviceSynchronize();
cudaError err = cudaGetLastError();
if (cudaSuccess != err)
{
std::cout << "Cuda kernel failed! " << cudaGetErrorString(err) <<std::endl;
}
start = std::chrono::steady_clock::now();
cudaMemcpy(interp_value_gpu, interp_value_device, result_size*fl_size, cudaMemcpyDeviceToHost);
auto elapsed_moving_back = std::chrono::steady_clock::now() - start;
float ms_moving_back = std::chrono::duration_cast<ms>(elapsed_moving_back).count();
std::cout << "Time spent moving the data to the GPU:" << ms_moving << " ms"<<std::endl;
std::cout << "Time spent moving the results back to the host: " << ms_moving_back << " ms" << std::endl;
cudaFree(interp_value_device);
cudaFree(weights_device);
cudaFree(node_map_device);
cudaFree(grid_values_device);
}
#包括“cuda_runtime.h”
#包括“设备启动参数.h”
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类型DEF浮动fl_类型；
typedef int pos_type；
typedef std:：chrono:：毫秒ms；
//cuda功能声明
void cuda_插值函数（fl_类型*内部值_back、int结果_size、fl_类型*网格值、int网格值_size、fl_类型*权重、pos_类型*节点图、int总动作_编号、int内部尺寸、int n_sim）；
fl_类型iterp_cpu（fl_类型*权重、pos_类型*节点图、fl_类型*网格值、int和row、int和column、int和interp dim、int和n sim）{
int w_p=列*内部尺寸；
fl_type res=权重[w_p]*网格值[row+节点映射[w_p]*n_sim]；
用于（int int int_point=1；int_pointn|sim | column>num|cols）返回；
fl_type res=权重[w_p]*网格值[row+节点映射[w_p]*n_sim]；
用于（int int int_point=1；int_pointn|sim | column>num|cols）返回；
fl_type res=权重[w_p]*网格值[row+节点映射[w_p]*n_sim]；
用于（int int int_point=1；int_pointCUDA memcheck
运行您的代码。最后一个实用程序类似于“启用内存检查器”在Nsight VSE中，但不完全相同。但是，Nsight VSE内存检查器可能会给出相同的指示
在C（或C++）中，数组的索引通常从0开始。因此，要测试越界索引，我必须检查生成的索引是否等于或大于数组的大小。但在您的情况下，您只测试大于：
if (row > n_sim || column > num_cols) return;
您在1D内核和2D内核中都犯了类似的错误，尽管您认为1D内核工作正常，但它实际上正在进行越界访问。如果您使用前面提到的cuda memcheck
实用程序（或者可能还使用可以在Nsight VSE中启用的内存检查器）运行，您可以验证这一点
当我在pastebin链接中修改您的代码以使用适当的范围/边界检查时，cuda memcheck
不会报告错误，并且您的程序会报告正确的结果。我已经测试了这两种情况，但下面的代码已从您的pastebin链接修改为取消注释2D情况，并使用该情况而不是1D情况：
$ cat t375.cu | more
#include "cuda_runtime.h"
#include "device_launch_parameters.h"
#include <stdio.h>
#include <assert.h>
#include <iostream>
#include <random>
#include <chrono>
typedef float fl_type;
typedef int pos_type;
typedef std::chrono::milliseconds ms;
//declaration of the cuda function
void cuda_interpolation_function(fl_type* interp_value_back, int result_size, fl
_type * grid_values, int grid_values_size, fl_type* weights, pos_type* node_map,
int total_action_number, int interp_dim, int n_sim);
fl_type iterp_cpu(fl_type* weights, pos_type* node_map, fl_type* grid_values, in
t& row, int& column, int& interp_dim, int& n_sim) {
int w_p = column*interp_dim;
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[node_map[w_p + inter_poi
nt] * n_sim + row];
}
return res;
}
__global__ void interp_kernel(fl_type * d_matrix, fl_type* weights, pos_type* no
de_map, fl_type* grid_values, int interp_dim, int n_sim, int num_cols) {
int index = blockIdx.x * blockDim.x + threadIdx.x;
int column = index / n_sim;
int row = index % n_sim;
int w_p = column*interp_dim;
if (row >= n_sim || column >= num_cols) return; // modified
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[row + node_map[w_p + int
er_point] * n_sim];
}
d_matrix[index] = res;
}
__global__ void interp_kernel2D(fl_type * d_matrix, fl_type* weights, pos_type*
node_map, fl_type* grid_values, int interp_dim, int n_sim, int num_cols) {
int column = blockIdx.x * blockDim.x + threadIdx.x;
int row = blockIdx.y * blockDim.y + threadIdx.y;
int index = column*n_sim + row;
int w_p = column*interp_dim;
if (row >= n_sim || column >= num_cols) return; // modified
fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
res += weights[w_p + inter_point] * grid_values[row + node_map[w_p + int
er_point] * n_sim];
}
d_matrix[index] = res;
}
void verify(fl_type *host, fl_type *device, int size) {
int count = 0;
int count_zero = 0;
for (int i = 0; i < size; i++) {
if (host[i] != device[i]) {
count++;
//std::cout <<"pos: " <<i<< " CPU:" <<h[i] << ", GPU: " << d[
i] <<std::endl;
assert(host[i] == device[i]);
if (device[i] == 0.0)
count_zero++;
}
}
if (count) {
std::cout << "Non matching: " << count << "out of " << size << "(" << (f
loat(count) / size * 100) << "%)" << std::endl;
std::cout << "Zeros returned from the device: " << count_zero <<"(" << (
float(count_zero) / size * 100) << "%)" << std::endl;
}
else
std::cout << "Perfect match!" << std::endl;
}
int main() {
int fl_size = sizeof(fl_type);
int pos_size = sizeof(pos_type);
int dim = 5; // range: 2-5
int number_nodes = 5500; // range: 10.000-500.000
int max_actions = 12; // range: 6-200
int n_sim = 1000; // range: 1.000-10.000
int interp_dim = std::pow(2, dim);
int grid_values_size = n_sim*number_nodes;
std::default_random_engine generator;
std::normal_distribution<fl_type> normal_dist(0.0, 1);
std::uniform_int_distribution<> uniform_dist(0, number_nodes - 1);
double bit_allocated = 0;
fl_type * grid_values; //flattened 2d array, containing the value of the grid (n_sims x number_nodes)
grid_values = (fl_type *)malloc(grid_values_size * fl_size);
bit_allocated += grid_values_size * fl_size;
for (int i = 0; i < grid_values_size; i++)
grid_values[i] = normal_dist(generator);
pos_type * map_node2values_start; //vector that maps each node to the first column of the result matrix regarding that done
pos_type * map_node2values_how_many; //vector that stores how many action we have per node
map_node2values_start = (pos_type *)malloc(number_nodes * pos_size);
map_node2values_how_many = (pos_type *)malloc(number_nodes * pos_size);
bit_allocated += 2 * (number_nodes * pos_size);
for (int i = 0; i < number_nodes; i++) {
//each node as simply max_actions
map_node2values_start[i] = max_actions*i;
map_node2values_how_many[i] = max_actions;
}
//total number of actions, which is amount of column of the results
int total_action_number = map_node2values_start[number_nodes - 1] + map_node2values_how_many[number_nodes - 1];
//vector that keep tracks of the columnt to grab, and their weight in the interpolation
fl_type* weights;
pos_type * node_map;
weights = (fl_type *)malloc(total_action_number*interp_dim * pos_size);
bit_allocated += total_action_number * fl_size;
node_map = (pos_type *)malloc(total_action_number*interp_dim * pos_size);
bit_allocated += total_action_number * pos_size;
//filling with random numbers
for (int i = 0; i < total_action_number*interp_dim; i++) {
node_map[i] = uniform_dist(generator); // picking random column
weights[i] = 1.0 / interp_dim; // uniform weights
}
std::cout << "done filling!" << std::endl;
std::cout << bit_allocated / 8 / 1024 / 1024 << "MB allocated" << std::endl;
int result_size = n_sim*total_action_number;
fl_type *interp_value_cpu;
bit_allocated += result_size* fl_size;
interp_value_cpu = (fl_type *)malloc(result_size* fl_size);
auto start = std::chrono::steady_clock::now();
for (int row = 0; row < n_sim; row++) {
for (int column = 0; column < total_action_number; column++) {
auto zz = iterp_cpu(weights, node_map, grid_values, row, column, interp_dim, n_sim);
interp_value_cpu[column*n_sim + row] = zz;
}
}
auto elapsed_cpu = std::chrono::steady_clock::now() - start;
std::cout << "Crunching values on the CPU (serial): " << std::chrono::duration_cast<ms>(elapsed_cpu).count() / 1000.0 << "s" << std::endl;
int * pp;
cudaMalloc((void**)&pp, sizeof(int)); //initializing the device, to not affect the benchmark
fl_type *interp_value_gpu;
interp_value_gpu = (fl_type *)malloc(result_size* fl_size);
start = std::chrono::steady_clock::now();
cuda_interpolation_function(interp_value_gpu, result_size, grid_values, grid_values_size, weights, node_map, total_action_number, interp_dim, n_sim);
auto elapsed_gpu = std::chrono::steady_clock::now() - start;
std::cout << "Crunching values on the GPU: " << std::chrono::duration_cast<ms>(elapsed_gpu).count() / 1000.0 << "s" << std::endl;
float ms_cpu = std::chrono::duration_cast<ms>(elapsed_cpu).count();
float ms_gpu = std::chrono::duration_cast<ms>(elapsed_gpu).count();
int n_proc = 4;
std::cout << "Performance: " << (ms_gpu- ms_cpu / n_proc) / (ms_cpu / n_proc) * 100 << " % less time than parallel CPU!" << std::endl;
verify(interp_value_cpu, interp_value_gpu, result_size);
free(interp_value_cpu);
free(interp_value_gpu);
free(grid_values);
free(node_map);
free(weights);
}
void cuda_interpolation_function(fl_type* interp_value_gpu, int result_size, fl_type * grid_values, int grid_values_size, fl_type* weights, pos_type* node_map, int total_action_number, int interp_dim, int n_sim) {
int fl_size = sizeof(fl_type);
int pos_size = sizeof(pos_type);
auto start = std::chrono::steady_clock::now();
//device versions of the inputs
fl_type * grid_values_device;
fl_type* weights_device;
pos_type * node_map_device;
fl_type *interp_value_device;
int lenght_node_map = interp_dim*total_action_number;
std::cout << "size grid_values: " << grid_values_size <<std::endl;
std::cout << "size weights: " << lenght_node_map << std::endl;
std::cout << "size interp_value: " << result_size << std::endl;
//allocating and moving to the GPU the inputs
auto error_code=cudaMalloc((void**)&grid_values_device, grid_values_size*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of the grid_values" << std::endl;
}
error_code=cudaMemcpy(grid_values_device, grid_values, grid_values_size*fl_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of the grid_values" << std::endl;
}
error_code=cudaMalloc((void**)&weights_device, lenght_node_map*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of the weights" << std::endl;
}
error_code=cudaMemcpy(weights_device, weights, lenght_node_map*fl_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of the weights" << std::endl;
}
error_code=cudaMalloc((void**)&node_map_device, lenght_node_map*pos_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of node_map" << std::endl;
}
error_code=cudaMemcpy(node_map_device, node_map, lenght_node_map*pos_size, cudaMemcpyHostToDevice);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMemcpy of node_map" << std::endl;
}
error_code=cudaMalloc((void**)&interp_value_device, result_size*fl_size);
if (error_code != cudaSuccess) {
std::cout << "Error during cudaMalloc of interp_value_device " << std::endl;
}
auto elapsed_moving = std::chrono::steady_clock::now() - start;
float ms_moving = std::chrono::duration_cast<ms>(elapsed_moving).count();
cudaDeviceSynchronize();
//1d
#if 0
int block_size = 1024;
int num_blocks = (result_size + block_size - 1) / block_size;
std::cout << "num_blocks:" << num_blocks << std::endl;
interp_kernel << < num_blocks, block_size >> > (interp_value_device, weights_device, node_map_device, grid_values_device, interp_dim, n_sim, total_action_number);
#endif
//2d
int block_size2 = 32; //each block will have block_size2*block_size2 threads
dim3 num_blocks2(block_size2, block_size2);
int x_grid = (total_action_number + block_size2 - 1) / block_size2;
int y_grid = (n_sim + block_size2 - 1) / block_size2;
dim3 grid_size2(x_grid, y_grid);
std::cout <<"grid:"<< x_grid<<" x "<< y_grid<<std::endl;
interp_kernel2D <<< grid_size2, num_blocks2 >>> (interp_value_device, weights_device, node_map_device, grid_values_device, interp_dim, n_sim, total_action_number);
cudaDeviceSynchronize();
cudaError err = cudaGetLastError();
if (cudaSuccess != err)
{
std::cout << "Cuda kernel failed! " << cudaGetErrorString(err) <<std::endl;
}
start = std::chrono::steady_clock::now();
cudaMemcpy(interp_value_gpu, interp_value_device, result_size*fl_size, cudaMemcpyDeviceToHost);
auto elapsed_moving_back = std::chrono::steady_clock::now() - start;
float ms_moving_back = std::chrono::duration_cast<ms>(elapsed_moving_back).count();
std::cout << "Time spent moving the data to the GPU:" << ms_moving << " ms"<<std::endl;
std::cout << "Time spent moving the results back to the host: " << ms_moving_back << " ms" << std::endl;
cudaFree(interp_value_device);
cudaFree(weights_device);
cudaFree(node_map_device);
cudaFree(grid_values_device);
}
$ nvcc -arch=sm_52 -o t375 t375.cu -std=c++11
$ cuda-memcheck ./t375
========= CUDA-MEMCHECK
done filling!
2.69079MB allocated
Crunching values on the CPU (serial): 30.081s
size grid_values: 5500000
size weights: 2112000
size interp_value: 66000000
grid:2063 x 32
Time spent moving the data to the GPU:31 ms
Time spent moving the results back to the host: 335 ms
Crunching values on the GPU: 7.089s
Performance: -5.73452 % less time than parallel CPU!
Perfect match!
========= ERROR SUMMARY: 0 errors
$
每当您在使用CUDA代码时遇到问题，我建议您进行适当的CUDA错误检查（这似乎是您经常做的），并使用CUDA memcheck
运行代码。最后一个实用程序类似于“启用内存检查器”在Nsight VSE中，但不完全相同。但是，Nsight VSE内存检查器可能会给出相同的指示
在C（或C++）中，数组的索引通常从0开始。因此，要测试越界索引，我必须检查生成的索引是否等于或大于数组的大小。但在您的情况下，您只测试大于：
if (row > n_sim || column > num_cols) return;
您在1D内核和2D内核中都犯了类似的错误，尽管您认为1D内核工作正常，但它实际上正在进行越界访问。如果您使用前面提到的cuda memcheck
实用程序（或者可能还使用可以在Nsight VSE中启用的内存检查器）运行，您可以验证这一点
当我在pastebin链接中修改您的代码以使用适当的范围/边界检查时，cuda memcheck
不会报告er
$ ./t375
done filling!
2.69079MB allocated
Crunching values on the CPU (serial): 30.273s
size grid_values: 5500000
size weights: 2112000
size interp_value: 66000000
grid:2063 x 32
Time spent moving the data to the GPU:32 ms
Time spent moving the results back to the host: 332 ms
Crunching values on the GPU: 1.161s
Performance: -84.6596 % less time than parallel CPU!
Perfect match!
$
if (row >= n_rows || column >= num_cols) return; // Do this
if (row > n_rows || column > num_cols) return; // Instead of this
int row = blockIdx.y * blockDim.y + threadIdx.y;
44. fl_type res = weights[w_p] * grid_values[row + node_map[w_p] * n_sim];
^^^
45. for (int inter_point = 1; inter_point < interp_dim; inter_point++) {
46. res += weights[w_p + inter_point] * \
grid_values[row + node_map[w_p + inter_point] * n_sim];
^^^
47. }