**external**
Prefix to specify loading an external I/O engine object file. Append
the engine filename, e.g. ``ioengine=external:/tmp/foo.o`` to load
- ioengine :file:`foo.o` in :file:`/tmp`.
+ ioengine :file:`foo.o` in :file:`/tmp`. The path can be either
+ absolute or relative. See :file:`engines/skeleton_external.c` for
+ details of writing an external I/O engine.
I/O engine specific parameters
*
* Should be compiled with:
*
- * gcc -Wall -O2 -g -shared -rdynamic -fPIC -o engine.o engine.c
+ * gcc -Wall -O2 -g -shared -rdynamic -fPIC -o skeleton_external.o skeleton_external.c
+ * (also requires -D_GNU_SOURCE -DCONFIG_STRSEP on Linux)
*
*/
#include <stdio.h>
#include <assert.h>
#include "../fio.h"
+#include "../optgroup.h"
/*
* The core of the module is identical to the ones included with fio,
* for external modules, they should be gotten through dlsym()
*/
+/*
+ * The io engine can define its own options within the io engine source.
+ * The option member must not be at offset 0, due to the way fio parses
+ * the given option. Just add a padding pointer unless the io engine has
+ * something usable.
+ */
+struct fio_skeleton_options {
+ void *pad; /* avoid ->off1 of fio_option becomes 0 */
+ unsigned int dummy;
+};
+
+static struct fio_option options[] = {
+ {
+ .name = "dummy",
+ .lname = "ldummy",
+ .type = FIO_OPT_STR_SET,
+ .off1 = offsetof(struct fio_skeleton_options, dummy),
+ .help = "Set dummy",
+ .category = FIO_OPT_C_ENGINE, /* always use this */
+ .group = FIO_OPT_G_INVALID, /* this can be different */
+ },
+ {
+ .name = NULL,
+ },
+};
+
/*
* The ->event() hook is called to match an event number with an io_u.
* After the core has called ->getevents() and it has returned eg 3,
.cleanup = fio_skeleton_cleanup,
.open_file = fio_skeleton_open,
.close_file = fio_skeleton_close,
+ .options = options,
+ .option_struct_size = sizeof(struct fio_skeleton_options),
};
.B external
Prefix to specify loading an external I/O engine object file. Append
the engine filename, e.g. `ioengine=external:/tmp/foo.o' to load
-ioengine `foo.o' in `/tmp'.
+ioengine `foo.o' in `/tmp'. The path can be either
+absolute or relative. See `engines/skeleton_external.c' in the fio source for
+details of writing an external I/O engine.
.SS "I/O engine specific parameters"
In addition, there are some parameters which are only valid when a specific
\fBioengine\fR is in use. These are used identically to normal parameters,