sender.c

#include "T.h"
#include <stdio.h>
#include <unistd.h>
#include <string.h>
#include <time.h>

#define NUM_SAMPLES 50000

FILE *fd;
long int collected_samples[2][NUM_SAMPLES];

double get_freq(void)
{
  FILE *cmd = popen("lscpu | grep max | awk '{print $4}' ", "r");
  if (cmd == NULL)
  {
    printf("Error reading file");
    return -1;
  }
  size_t n;
  char buff[80];
  if ((n = fread(buff, 1, sizeof(buff) - 1, cmd)) <= 0)
    return -1;
  char *token = strtok(buff, "\n");
  double ret = 0.0;
  sscanf(token, "%lf", &ret);
  return ret;
}

/*Get the value of rdtsc*/
unsigned long int timestamp(void)
{
  unsigned long int result;
  unsigned int bottom;
  unsigned int top;
  asm volatile("rdtsc"
               : "=a"(bottom), "=d"(top));
  result = top;
  result = (result << 32) & 0xFFFFFFFF00000000UL;
  return (result | bottom);
}

/*Get the value of a memory location*/
long int mem_access(long int *v)
{
  long int rv = 0;
  asm volatile(
      "movq (%1), %0"
      : "+r"(rv)
      : "r"(v)
      :);
  return rv;
}

/*Measure read time*/
int access_timed(long int *pos_data)
{
  volatile unsigned int time;
  asm __volatile__(
      //" mfence \n"
      //" lfence \n"
      " rdtsc \n"
      " lfence \n"
      " movl %%eax, %%esi \n"
      " movl (%1), %%eax \n"
      " lfence \n"
      " rdtsc \n"
      " subl %%esi, %%eax \n"
      : "=a"(time)
      : "c"(pos_data)
      : "%esi", "%edx");
  return time;
}

int main()
{
  int i;
  int target;
  long int sleep_time; //nanoseconds
  long int wait_time;  //cycles
  long int *target_address;
  char *quixote;
  char file_name[40];
  double cpu_time_used;
  struct timespec request, remain;
  clock_t start, end;

  double p = get_freq();

  printf("Enter target address (int)\n");
  scanf("%d", &target);
  //quixote = (char *)get_address_quixote(target);
  target_address = (long int *)get_address_table(target);
  printf("Target address %lx \n", (long int)target_address);
  //printf("%c \n", *quixote);
  while (1)
  {
    printf("Enter sleep time \n");
    scanf("%ld", &sleep_time);
    /*Setup timer*/
    if (sleep_time > 50000)
    {
      request.tv_sec = (int)((sleep_time - 10) / 1000000000);
      request.tv_nsec = (long)((sleep_time - 10) % 1000000000);
    }
    else
    {
      wait_time = (long int)(((p) * sleep_time) / 1000);
    }
    snprintf(file_name, 40, "sender_%d_%ld.txt", target, sleep_time);
    printf("Saving results to %s %lu %lu\n", file_name, request.tv_sec, request.tv_nsec);
    fd = fopen(file_name, "w");
    if (fd == NULL)
      fprintf(stderr, "Unable to open file\n");
    for (i = 0; i < NUM_SAMPLES; i++)
    {
      if (sleep_time > 50000)
      {
        nanosleep(&request, &remain);
      }
      else
      {
        unsigned long int t1 = timestamp() + wait_time;
        while (timestamp() < t1)
          ;
      }
      //collected_samples[0][i] = mem_access(target_address);
      collected_samples[0][i] = access_timed(target_address);
      //mem_access(target_address + 1);
      //access_timed(target_address+1);
      //access_timed(target_address+2);
      collected_samples[1][i] = timestamp();
    }
    for (i = 0; i < NUM_SAMPLES; i++)
    {
      fprintf(fd, "%lu %lu\n", collected_samples[0][i], collected_samples[1][i]);
    }
    fclose(fd);
  }
  return 0;
}