Initial commit.

[collect-bench] / benchspt.c

#include <errno.h>
#include <stdlib.h>
#include <time.h>

#if defined(__GNUC__) && (defined(__i386__) || defined (__x86_64__))

struct cycle_counter {
  char dummy;
};

static int init_counter(struct cycle_counter *cy) { return (0); }
static void teardown_counter(struct cycle_counter *cy) { ; }

int cycles(struct cycle_counter *cy, unsigned long long *t_out)
{
  unsigned lo, hi;

  __asm__("rdtsc" : "=a"(lo), "=d"(hi));
  *t_out = lo | ((unsigned long long)hi << 32);
  return (0);
}

#elif defined(__linux__)

#include <unistd.h>
#include <linux/perf_event.h>
#include <asm/unistd.h>

struct cycle_counter {
  int fd;
};

static int init_counter(struct cycle_counter *cy)
{
  struct perf_event_attr attr = { 0 };

  attr.type = PERF_TYPE_HARDWARE;
  attr.size = sizeof(attr);
  attr.config = PERF_COUNT_HW_CPU_CYCLES;
  attr.disabled = 0;
  attr.exclude_kernel = 1;
  attr.exclude_hv = 1;

  cy->fd = syscall(__NR_perf_event_open, &attr, 0, -1, -1, 0);
  if (cy->fd < 0) return (-1);
  return (0);
}

static void teardown_counter(struct cycle_counter *cy)
  { if (cy->fd >= 0) close(cy->fd); }

int cycles(struct cycle_counter *cy, unsigned long long *t_out)
{
  ssize_t n;

  if (cy->fd < 0) { errno = EBADF; return (-1); }
  n = read(cy->fd, t_out, sizeof(*t_out));
  if (n < sizeof(*t_out)) {
    if (n >= 0) errno = ENODATA;
    close(cy->fd); cy->fd = -1;
    return (-1);
  }
  return (0);
}

#else

struct cycle_counter {
  char dummy;
};

static int init_counter(struct cycle_counter *cy)
  { errno = ENOSYS; return (-1); }
static void teardown_counter(struct cycle_counter *cy) { ; }
int cycles(struct cycle_counter *cy, unsigned long long *t_out)
  { return (-1); }

#endif

struct cycle_counter *open_cycle_counter(void)
{
  struct cycle_counter *cy = 0, *cy_ret = 0;

  cy = malloc(sizeof(*cy)); if (!cy) goto end;
  if (init_counter(cy)) goto end;
  cy_ret = cy; cy = 0;
end:
  free(cy);
  return (cy_ret);
}

void close_cycle_counter(struct cycle_counter *cy)
  { teardown_counter(cy); free(cy); }

struct clock {
  long long sec;
  unsigned nsec;
};

int thread_clock(struct clock *clk_out)
{
  struct timespec tv;

  if (clock_gettime(CLOCK_THREAD_CPUTIME_ID, &tv)) return (-1);
  clk_out->sec = tv.tv_sec; clk_out->nsec = tv.tv_nsec;
  return (0);
}

int get_errno(void) { return (errno); }