something i have trouble about cuda runtime version

my system is this

CUDA 8.0

UBUNTU 16.04 LTS

nvcc: NVIDIA ® Cuda compiler driver
Copyright © 2005-2016 NVIDIA Corporation
Built on Tue_Jan_10_13:22:03_CST_2017
Cuda compilation tools, release 8.0, V8.0.61

in bash.rc
export CUDA_HOME=/usr/local/cuda-8.0
export PATH=/usr/local/cuda-8.0/bin${PATH:+:{PATH}} export LD_LIBRARY_PATH=/usr/local/cuda-8.0/lib64{LD_LIBRARY_PATH:+:${LD_LIBRARY_PATH}}

i spend time about cuda tutorial

first i write ex1.cu

#include
#include <stdio.h>
#include “common/book.h”
global void add(int a, int b, int *c){
*c=a+b;

}

int main(){

int c;
int *dev_c;
HANDLE_ERROR(cudaMalloc( (void**)&dev_c, sizeof(int) ) );
add<<<1,1>>>(2,7, dev_c);
HANDLE_ERROR( cudaMemcpy( &c, dev_c, sizeof(int),cudaMemcpyDeviceToHost));

printf("2+7 = %d",c);
cudaFree(dev_c);
return 0;

}

and i compiled then it occured

won@won-desktop:~/cuda_example$ nvcc ex1.cu
nvcc warning : The ‘compute_20’, ‘sm_20’, and ‘sm_21’ architectures are deprecated, and may be removed in a future release (Use -Wno-deprecated-gpu-targets to suppress warning).
won@won-desktop:~/cuda_example$ ./a.out
CUDA driver version is insufficient for CUDA runtime version in ex1.cu at line 14

Your CUDA install is broken. If you google that error message:

CUDA driver version is insufficient for CUDA runtime version

you will find many descriptions/writeups.

then i should be reinstall vga driver or cuda 8.0?

either will fix it, if you do it correctly

You must install a driver revision which contains CUDA 8.0 runtime (or newer, but matching is always best)

The SDK is only the SDK, no runtime. However the SDK suggests/includes an optional driver which matches the SDK version, which brings in the runtime (so I guess a runtime does come with the SDK but it’s an additional step really)

You must not have installed a proprietary driver / still on nouveau or such else useless 2D open-source drivers.