Merge branch 'doc-patches' of https://github.com/vincentkfu/fio

[fio.git] / engines / null.c

diff --git a/engines/null.c b/engines/null.c
index cd446b99971c5ada0cd283348877203717585217..812cadfe5ba8910018e6d98ca75ce7f3f88fe66e 100644 (file)
--- a/engines/null.c
+++ b/engines/null.c
@@ -1,5 +1,12 @@
 /*
- * null engine - doesn't do any transfers. Used to test fio.
+ * null engine
+ *
+ * IO engine that doesn't do any real IO transfers, it just pretends to.
+ * The main purpose is to test fio itself.
+ *
+ * It also can act as external C++ engine - compiled with:
+ *
+ * g++ -O2 -g -shared -rdynamic -fPIC -o null.so null.c -DFIO_EXTERNAL_ENGINE
  *
  */
 #include <stdio.h>
@@ -9,50 +16,109 @@
 #include <assert.h>
 
 #include "../fio.h"
-#include "../os.h"
 
-static int fio_null_queue(struct thread_data fio_unused *td, struct io_u *io_u)
+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)
 {
-       io_u->resid = 0;
-       io_u->error = 0;
-       return FIO_Q_COMPLETED;
+       struct null_data *nd = (struct null_data *) td->io_ops_data;
+
+       return nd->io_us[event];
 }
 
-static int fio_null_setup(struct thread_data *td)
+static int fio_null_getevents(struct thread_data *td, unsigned int min_events,
+                             unsigned int fio_unused max,
+                             const struct timespec fio_unused *t)
 {
-       struct fio_file *f;
-       int i;
-
-       if (!td->total_file_size) {
-               log_err("fio: need size= set\n");
-               return 1;
+       struct null_data *nd = (struct null_data *) td->io_ops_data;
+       int ret = 0;
+       
+       if (min_events) {
+               ret = nd->events;
+               nd->events = 0;
        }
 
-       td->io_size = td->total_file_size;
-       td->total_io_size = td->io_size;
+       return ret;
+}
+
+static int fio_null_commit(struct thread_data *td)
+{
+       struct null_data *nd = (struct null_data *) td->io_ops_data;
 
-       for_each_file(td, f, i) {
-               f->real_file_size = td->total_io_size / td->nr_files;
-               f->file_size = f->real_file_size;
+       if (!nd->events) {
+#ifndef FIO_EXTERNAL_ENGINE
+               io_u_mark_submit(td, nd->queued);
+#endif
+               nd->events = nd->queued;
+               nd->queued = 0;
        }
 
        return 0;
 }
 
+static int fio_null_queue(struct thread_data *td, struct io_u *io_u)
+{
+       struct null_data *nd = (struct null_data *) 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)
 {
-       f->fd = 0;
        return 0;
 }
 
+static void fio_null_cleanup(struct thread_data *td)
+{
+       struct null_data *nd = (struct null_data *) td->io_ops_data;
+
+       if (nd) {
+               free(nd->io_us);
+               free(nd);
+       }
+}
+
+static int fio_null_init(struct thread_data *td)
+{
+       struct null_data *nd = (struct null_data *) malloc(sizeof(*nd));
+
+       memset(nd, 0, sizeof(*nd));
+
+       if (td->o.iodepth != 1) {
+               nd->io_us = (struct io_u **) 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;
+}
+
+#ifndef __cplusplus
 static struct ioengine_ops ioengine = {
        .name           = "null",
        .version        = FIO_IOOPS_VERSION,
-       .setup          = fio_null_setup,
        .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_SYNCIO | FIO_DISKLESSIO,
+       .flags          = FIO_DISKLESSIO | FIO_FAKEIO,
 };
 
 static void fio_init fio_null_register(void)
@@ -64,3 +130,28 @@ static void fio_exit fio_null_unregister(void)
 {
        unregister_ioengine(&ioengine);
 }
+
+#else
+
+#ifdef FIO_EXTERNAL_ENGINE
+extern "C" {
+static struct ioengine_ops ioengine;
+void get_ioengine(struct ioengine_ops **ioengine_ptr)
+{
+       *ioengine_ptr = &ioengine;
+
+       ioengine.name           = "cpp_null";
+       ioengine.version        = FIO_IOOPS_VERSION;
+       ioengine.queue          = fio_null_queue;
+       ioengine.commit         = fio_null_commit;
+       ioengine.getevents      = fio_null_getevents;
+       ioengine.event          = fio_null_event;
+       ioengine.init           = fio_null_init;
+       ioengine.cleanup        = fio_null_cleanup;
+       ioengine.open_file      = fio_null_open;
+       ioengine.flags          = FIO_DISKLESSIO | FIO_FAKEIO;
+}
+}
+#endif /* FIO_EXTERNAL_ENGINE */
+
+#endif /* __cplusplus */