OpenACC 与 CUDA 的相互调用

▶ 按照书上的代码完成了 OpenACC 与CUDA 的相互调用，以及 OpenACC 调用 cuBLAS。便于过程遇到了很多问题，注入 CUDA 版本，代码版本，计算能力指定等，先放在这里，以后填坑。

● 代码，OpenACC 调用 CUDA

 // kernel.cu
 __global__ void saxpy_kernel(const int n, const float a, float *x, float *y)
 {
     int id = blockIdx.x * blockDim.x + threadIdx.x;
     if (id < n)
         y[id] += a * x[id];
 }

 extern "C" void saxpy(const int n, const float a, float *x, float *y)
 {
     saxpy_kernel << < (n +  - ) / ,  >> > (n, a, x, y);
 }

 // main.c
 #include <stdio.h>
 #include <stdlib.h>

 #define N   1024

 #pragma acc routine seq
 extern void saxpy(int n, float a, float *x, float *y);

 int main()
 {
     float *x = (float *)malloc(sizeof(float)*N);
     float *y = (float *)malloc(sizeof(float)*N);

 #pragma acc data create(x[0:N]) copyout(y[0:N])
     {
 #pragma acc kernels
 #pragma acc loop independent
         for (int i = ; i < N; i++)
         {
             x[i] = 1.0f;
             y[i] = 4.0f;
         }
 #pragma acc host_data use_device(x, y)
         saxpy(N, 2.0f, x, y);
     }
 #pragma wait

     printf("\ny[0] = %f\n", y[]);
     free(x);
     free(y);
     //getchar();
     return ;
 }

● 输出结果，代码在 win10上不能链接，报错：LINK : fatal error LNK1104: 无法打开文件“libcudapgi.lib”，WSL上输出结果不正确，在 Ubuntu 中报链接错误。参考了 参考https://blog.csdn.net/wcj0626/article/details/12611689?locationNum=12&fps=1 和 https://stackoverflow.com/questions/31737024/openacc-calling-cuda-device-kernel-from-openacc-parallel-loop，还是没有解决问题

WSL:
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ nvcc -c kernel.cu -rdc=true
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -acc -c main.c
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -ta=tesla:rdc,cuda9. -Mcuda -o acc.exe main.o kernel.o
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ ./acc.exe

y[] = 4.000000

Ubuntu:
@E@nvlink fatal   : elfLink fatbinary error
pgacclnk: child process exit status : /usr/local/pgi/linux86-/18.4/bin/pgnvd

● 代码，OpenACC 调用 CUDA

 // fun.c
 void set(const int n, const float c, float *x)
 {
 #pragma acc kernels deviceptr(x)
     for (int i = ; i < n; i++)
         x[i] = c;
 }

 void saxpy(const int n, const float a, float *restrict x, float *restrict y)
 {
 #pragma acc kernels deviceptr(x, y)
     for (int i = ; i < n; i++)
         y[i] += a * x[i];
 }

 // main.cu
 #include <stdio.h>
 #include <cuda.h>
 #include "cuda_runtime.h"
 #include "device_launch_parameters.h"

 #define N   1024

 extern "C" void set(int, float, float *);
 extern "C" void saxpy(int, float, float *, float *);

 int main()
 {
     float *x, *y, y0;
     cudaMalloc((void**)&x, sizeof(float)*N);
     cudaMalloc((void**)&y, sizeof(float)*N);

     set(N, 1.0f, x);
     set(N, 0.0f, y);
     saxpy(N, 2.0f, x, y);
     cudaMemcpy(&y0, y, sizeof(float), cudaMemcpyDeviceToHost);

     printf("\ny[0] = %f\n", y0);
     cudaFree(x);
     cudaFree(y);
     //getchar();
     return ;
 }

● 输出结果，代码在 win10上不能链接，WSL 和 Ubuntu 中报链接错误

WSL:
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ nvcc -c main.cu -rdc=true
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -acc -c fun.c
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -ta=tesla:rdc,cuda9. -Mcuda -o acc.exe main.o fun.o
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ ./acc.exe
Segmentation fault (core dumped)

Ubuntu:
cuan@CUAN:~/Temp$ nvcc -c main.cu -rdc=true
cuan@CUAN:~/Temp$ pgcc -acc -c fun.c
cuan@CUAN:~/Temp$ pgcc -ta=tesla:rdc,cuda9. -Mcuda -o acc.exe main.o fun.o
@E@nvlink fatal   : elfLink fatbinary error
pgacclnk: child process exit status : /usr/local/pgi/linux86-/18.4/bin/pgnvd

● 代码，CUDA 调用 OpenACC，捆绑变量地址

 // fun.c
 #include <openacc.h>

 void map(float *restrict pHost, float *restrict pDevice, int sizeByte)
 {
     acc_map_data(pHost, pDevice, sizeByte);
 }

 void set(int n, float c, float *x)
 {
 #pragma acc kernels present(x)
     for (int i = ; i < n; i++)
         x[i] = c;
 }

 void saxpy(int n, float a, float *restrict x, float *restrict y)
 {
 #pragma acc kernels deviceptr(x,y)
     for (int i = ; i < n; i++)
         y[i] += a * x[i];
 }

 // main.cu
 #include <stdio.h>
 #include <stdlib.h>

 #define N   1024

 extern "C" void map(float *, float *, int);
 extern "C" void set(int, float, float *);
 extern "C" void saxpy(int, float, float *, float *);

 int main()
 {

     float *x = (float *)malloc(sizeof(float)*N);
     float *y = (float *)malloc(sizeof(float)*N);
     float *dx, *dy, y0;
     cudaMalloc((void**)&dx, sizeof(float)*N);
     cudaMalloc((void**)&dy, sizeof(float)*N);

     map(x, dx, sizeof(float)*N);
     map(y, dy, sizeof(float)*N);
     set(N, 1.0f, x);
     set(N, 4.0f, y);
     saxpy(N, 2.0f, x, y);
     cudaMemcpy(&y0, y, sizeof(float), cudaMemcpyDeviceToHost);

     printf("\ny[0] = %f\n",y0);
     free(x);
     free(y);
     cudaFree(x);
     cudaFree(y);
     //getchar();
     return ;
 }

● 输出结果，代码在 win10上不能链接，在 WSL 上结果正确，在 Ubuntu 中未尝试

WSL:
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ nvcc -c main.cu -rdc=true
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -c fun.c -acc
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -acc -Mcuda -o acc.exe main.o fun.o -ta=tesla:rdc,cuda9.
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ ./acc.exe

y[] = 6.000000

● 代码，OpenACC 调用 cuBLAS

 #include <stdio.h>
 #include <stdlib.h>

 #define N   1024

 extern void cublasSaxpy(int, float, float *, int, float *, int);

 int main()
 {
     float *x = (float *)malloc(sizeof(float)*N);
     float *y = (float *)malloc(sizeof(float)*N);

 #pragma acc data create(x[0:N]) copyout(y[0:N])
     {
 #pragma acc kernels
         for (int i = ; i < N; i++)
         {
             x[i] = 1.0f;
             y[i] = 4.0f;
         }
 #pragma acc host_data use_device(x,y)
         {
             cublasSaxpy(N, 2.0f, x, , y, );
         }
     }

     printf("\ny[0] = %f\n", y[]);
     free(x);
     free(y);
     //getchar();
     return ;
 }

● 输出结果，代码在 win10上不能链接，在 WSL 中结果错误，在 Ubuntu 中结果正确

WSL:
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ nvcc -c fun.c -rdc=true
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -acc -c main.c
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ pgcc -acc -Mcuda -lcublas -o acc.exe main.o
cuan@CUAN:/mnt/d/Code/CUDA/cudaProject/cudaProject$ ./acc.exe

y[] = 4.000000

Ubuntu:
cuan@CUAN:~/Temp$ nvcc -c fun.c -rdc=true
cuan@CUAN:~/Temp$ pgcc -acc -c main.c
cuan@CUAN:~/Temp$ pgcc -acc -Mcuda -lcublas -o acc.exe main.o
cuan@CUAN:~/Temp$ ./acc.exe

y[] = 6.000000