Timing CUDA GPU code. Source: https://github.com/udacity/cs344/blob/master/Unit2%20Code%20Snippets/gputimer.h

gputimer.cuh

#ifndef __GPU_TIMER_H__
#define __GPU_TIMER_H__

#include <cuda_runtime.h>

struct GpuTimer
{
      cudaEvent_t start;
      cudaEvent_t stop;
 
      GpuTimer()
      {
            cudaEventCreate(&start);
            cudaEventCreate(&stop);
      }
 
      ~GpuTimer()
      {
            cudaEventDestroy(start);
            cudaEventDestroy(stop);
      }
 
      void Start()
      {
            cudaEventRecord(start, 0);
      }
 
      void Stop()
      {
            cudaEventRecord(stop, 0);
      }
 
      float Elapsed()
      {
            // Returns elapsed time in msecs.
            float elapsed;
            cudaEventSynchronize(stop);
            cudaEventElapsedTime(&elapsed, start, stop);
            return elapsed;
      }
};

typedef struct GpuTimer GpuTimer;

#endif /* __GPU_TIMER_H__ */