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Sourcecode: fio version File versions

gettime.c

/*
 * Clock functions
 */

#include <unistd.h>
#include <sys/time.h>

#include "fio.h"
#include "smalloc.h"

#include "hash.h"

static int clock_gettime_works;
static struct timeval last_tv;
static int last_tv_valid;

static struct timeval *fio_tv;
int fio_gtod_offload = 0;
int fio_gtod_cpu = -1;

#ifdef FIO_DEBUG_TIME

#define HASH_BITS 8
#define HASH_SIZE (1 << HASH_BITS)

static struct flist_head hash[HASH_SIZE];
static int gtod_inited;

struct gtod_log {
      struct flist_head list;
      void *caller;
      unsigned long calls;
};

static struct gtod_log *find_hash(void *caller)
{
      unsigned long h = hash_ptr(caller, HASH_BITS);
      struct flist_head *entry;

      flist_for_each(entry, &hash[h]) {
            struct gtod_log *log = flist_entry(entry, struct gtod_log,
                                                      list);

            if (log->caller == caller)
                  return log;
      }

      return NULL;
}

static struct gtod_log *find_log(void *caller)
{
      struct gtod_log *log = find_hash(caller);

      if (!log) {
            unsigned long h;

            log = malloc(sizeof(*log));
            INIT_FLIST_HEAD(&log->list);
            log->caller = caller;
            log->calls = 0;

            h = hash_ptr(caller, HASH_BITS);
            flist_add_tail(&log->list, &hash[h]);
      }

      return log;
}

static void gtod_log_caller(void *caller)
{
      if (gtod_inited) {
            struct gtod_log *log = find_log(caller);

            log->calls++;
      }
}

static void fio_exit fio_dump_gtod(void)
{
      unsigned long total_calls = 0;
      int i;

      for (i = 0; i < HASH_SIZE; i++) {
            struct flist_head *entry;
            struct gtod_log *log;

            flist_for_each(entry, &hash[i]) {
                  log = flist_entry(entry, struct gtod_log, list);

                  printf("function %p, calls %lu\n", log->caller,
                                                log->calls);
                  total_calls += log->calls;
            }
      }

      printf("Total %lu gettimeofday\n", total_calls);
}

static void fio_init gtod_init(void)
{
      int i;

      for (i = 0; i < HASH_SIZE; i++)
            INIT_FLIST_HEAD(&hash[i]);

      gtod_inited = 1;
}

#endif /* FIO_DEBUG_TIME */

#ifdef FIO_DEBUG_TIME
void fio_gettime(struct timeval *tp, void *caller)
#else
void fio_gettime(struct timeval *tp, void fio_unused *caller)
#endif
{
#ifdef FIO_DEBUG_TIME
      if (!caller)
            caller = __builtin_return_address(0);

      gtod_log_caller(caller);
#endif
      if (fio_tv) {
            memcpy(tp, fio_tv, sizeof(*tp));
            return;
      } else if (!clock_gettime_works) {
gtod:
            gettimeofday(tp, NULL);
      } else {
            struct timespec ts;

            if (clock_gettime(CLOCK_MONOTONIC, &ts) < 0) {
                  clock_gettime_works = 0;
                  goto gtod;
            }

            tp->tv_sec = ts.tv_sec;
            tp->tv_usec = ts.tv_nsec / 1000;
      }

      /*
       * If Linux is using the tsc clock on non-synced processors,
       * sometimes time can appear to drift backwards. Fix that up.
       */
      if (last_tv_valid) {
            if (tp->tv_sec < last_tv.tv_sec)
                  tp->tv_sec = last_tv.tv_sec;
            else if (last_tv.tv_sec == tp->tv_sec &&
                   tp->tv_usec < last_tv.tv_usec)
                  tp->tv_usec = last_tv.tv_usec;
      }
      last_tv_valid = 1;
      memcpy(&last_tv, tp, sizeof(*tp));
}

void fio_gtod_init(void)
{
      fio_tv = smalloc(sizeof(struct timeval));
      assert(fio_tv);
}

void fio_gtod_update(void)
{
      gettimeofday(fio_tv, NULL);
}

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