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Sourcecode: fio version File versions

null.c

/*
 * null engine
 *
 * IO engine that doesn't do any real IO transfers, it just pretends to.
 * The main purpose is to test fio itself.
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>

#include "../fio.h"

struct null_data {
      struct io_u **io_us;
      int queued;
      int events;
};

static struct io_u *fio_null_event(struct thread_data *td, int event)
{
      struct null_data *nd = td->io_ops->data;

      return nd->io_us[event];
}

static int fio_null_getevents(struct thread_data *td, unsigned int min_events,
                        unsigned int fio_unused max,
                        struct timespec fio_unused *t)
{
      struct null_data *nd = td->io_ops->data;
      int ret = 0;
      
      if (min_events) {
            ret = nd->events;
            nd->events = 0;
      }

      return ret;
}

static int fio_null_commit(struct thread_data *td)
{
      struct null_data *nd = td->io_ops->data;

      if (!nd->events) {
            io_u_mark_submit(td, nd->queued);
            nd->events = nd->queued;
            nd->queued = 0;
      }

      return 0;
}

static int fio_null_queue(struct thread_data fio_unused *td, struct io_u *io_u)
{
      struct null_data *nd = td->io_ops->data;

      fio_ro_check(td, io_u);

      if (td->io_ops->flags & FIO_SYNCIO)
            return FIO_Q_COMPLETED;
      if (nd->events)
            return FIO_Q_BUSY;

      nd->io_us[nd->queued++] = io_u;
      return FIO_Q_QUEUED;
}

static int fio_null_open(struct thread_data fio_unused *td,
                   struct fio_file fio_unused *f)
{
      return 0;
}

static void fio_null_cleanup(struct thread_data *td)
{
      struct null_data *nd = td->io_ops->data;

      if (nd) {
            if (nd->io_us)
                  free(nd->io_us);
            free(nd);
      }
}

static int fio_null_init(struct thread_data *td)
{
      struct null_data *nd = malloc(sizeof(*nd));

      memset(nd, 0, sizeof(*nd));

      if (td->o.iodepth != 1) {
            nd->io_us = malloc(td->o.iodepth * sizeof(struct io_u *));
            memset(nd->io_us, 0, td->o.iodepth * sizeof(struct io_u *));
      } else
            td->io_ops->flags |= FIO_SYNCIO;

      td->io_ops->data = nd;
      return 0;
}

static struct ioengine_ops ioengine = {
      .name       = "null",
      .version    = FIO_IOOPS_VERSION,
      .queue            = fio_null_queue,
      .commit           = fio_null_commit,
      .getevents  = fio_null_getevents,
      .event            = fio_null_event,
      .init       = fio_null_init,
      .cleanup    = fio_null_cleanup,
      .open_file  = fio_null_open,
      .flags            = FIO_DISKLESSIO,
};

static void fio_init fio_null_register(void)
{
      register_ioengine(&ioengine);
}

static void fio_exit fio_null_unregister(void)
{
      unregister_ioengine(&ioengine);
}

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