HM-MOD-UART-RPI latency test

aculfw_latencytest.cpp

#include <iostream>
#include <errno.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdexcept>
#include <string.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

#include <chrono>


using namespace std;

int main(int argc, char *argv[]) {
  if (argc != 2) {
    std::cout << "not enough parameters" << std::endl;
  }

  const unsigned char reqCredits[] = {0xfd, 0x00, 0x03, 0x00, 0x50, 0x08, 0xf8, 0x36};

  const std::string iface = argv[1];

  int fd = open(iface.c_str(), O_RDWR);
  if (fd < 0)
    throw std::runtime_error(
        std::string("Could not open device: ") + iface);

  srand (time(NULL));
  //  close(fd);
  //  return 0;
  unsigned long writeCount = 0;

  std::cout << "Starting..." << std::endl;

  char buffer[256];
  while (true) {
    int sl = 1500 + (rand() % 2000);
    sl *= 1000;
    usleep(sl);

    auto start = std::chrono::system_clock::now();

    int writeRc = write(fd, reqCredits, sizeof(reqCredits));
    int readCount = read(fd, buffer, 256);

    auto end = std::chrono::system_clock::now();
    auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);

    std::cout << "Slept: " << sl / 1000000.0f << " s \t\tRRT: " << elapsed.count() << std::endl;

  }
  return 0;
}