#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <libpmem.h>
#include <sys/time.h>
//编译运行
//g++ DRAM_NVM_Bandwidth.cpp -o DRAM_NVM_Bandwidth -lpmem

//NOTE：
//每次运行后，去PATH路径下删除生成的文件，才可以运行第二次。

//详情：
//https://pmem.io/pmdk/

/* using 4k of pmem for this example */
// 1GB
#define PMEM_LEN 1073741824
// #define PMEM_LEN 16384
#define PATH "/mnt/pmem/test_lz"

int main(int argc, char *argv[])
{
    struct timeval tvs,tve;
    char *pmemaddr1;       //这个就是NVM上的地址
    char *pmemaddr2;       //这个就是NVM上的地址
    size_t mapped_len; //NVM文件的总大小
    int is_pmem1;      //是否识别为持久性内存，1 是 ，0 否。 假如为0的话表示PATH这个地址现在不是在NVM上（要重新挂载一下） -命令： mount -o dax,noatime /dev/pmem0 /mnt/pmem/
    int is_pmem2;
    char *dramaddr1;
    char *dramaddr2;
    dramaddr1 = (char *)malloc(PMEM_LEN);
    dramaddr2 = (char *)malloc(PMEM_LEN);
    /* create a pmem file and memory map it */
    if ((pmemaddr1 = (char *)pmem_map_file(PATH, PMEM_LEN, PMEM_FILE_CREATE,
                                          0666, &mapped_len, &is_pmem1)) == NULL)
    {
        perror("pmem_map_file");
        exit(1);
    }

    if ((pmemaddr2 = (char *)pmem_map_file(PATH, PMEM_LEN, PMEM_FILE_CREATE,
                                          0666, &mapped_len, &is_pmem2)) == NULL)
    {
        perror("pmem_map_file");
        exit(1);
    }

    printf("%d   %d\n", is_pmem1,is_pmem2); //假如为 1 ，后面就可以用这个指针了

    /* store a string to the persistent memory */
    // pmem_memset_persist(pmemaddr1, '1', PMEM_LEN); 
    /*
        ***************************************************************************
        ************************* DRAM -> NVM *************************************
        ***************************************************************************

    */
    memset(dramaddr1, 'b', PMEM_LEN); 

    gettimeofday(&tvs,NULL);
    // memcpy(pmemaddr1,dramaddr,PMEM_LEN);
    pmem_memcpy(pmemaddr1,dramaddr1,PMEM_LEN,0);
    // pmem_memcpy_nodrain(pmemaddr1,dramaddr,PMEM_LEN);
    gettimeofday(&tve,NULL);
    // second
    double span = tve.tv_sec-tvs.tv_sec + (tve.tv_usec-tvs.tv_usec)/1000000.0;
    printf("DRAM -> NVM time: %.4f\n",span);
    printf("The DRAM to NVM bandwidth is: %.4f GB/s\n",PMEM_LEN/1024/1024/1024/span);
    // printf("%c\n",pmemaddr1[0]);
    /*
        ***************************************************************************
        ************************* NVM -> DRAM *************************************
        ***************************************************************************

    */

    // pmem_memset_persist(pmemaddr, '1', PMEM_LEN); 
    memset(pmemaddr2, 'c', PMEM_LEN); 
    gettimeofday(&tvs,NULL);
    pmem_memcpy(dramaddr2,pmemaddr2,PMEM_LEN,0);
    gettimeofday(&tve,NULL);
    // second
    span = tve.tv_sec-tvs.tv_sec + (tve.tv_usec-tvs.tv_usec)/1000000.0;
    printf("NVM -> DRAM time: %.4f\n",span);
    printf("The NVM to DRAM bandwidth is: %.4f GB/s\n",PMEM_LEN/1024/1024/1024/span);
    printf("%c\n",dramaddr2[0]);
}