From d243fd6ddefe748e307170d464120c962d5938a4 Mon Sep 17 00:00:00 2001 From: Tomohiro Kusumi Date: Thu, 31 Aug 2017 23:13:04 +0300 Subject: [PATCH 1/1] skeleton: add option example Add an example of ioengine specific options, which can/should exist within each ioengine code. Also fix/add documentation. Also see e59b9e11('move skip_bad= option to engines/mtd.c'). Signed-off-by: Tomohiro Kusumi Signed-off-by: Jens Axboe --- HOWTO | 4 +++- engines/skeleton_external.c | 32 +++++++++++++++++++++++++++++++- fio.1 | 4 +++- 3 files changed, 37 insertions(+), 3 deletions(-) diff --git a/HOWTO b/HOWTO index 3a720c35..2a70b7c6 100644 --- a/HOWTO +++ b/HOWTO @@ -1791,7 +1791,9 @@ I/O engine **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 diff --git a/engines/skeleton_external.c b/engines/skeleton_external.c index 4bebcc45..56f89f95 100644 --- a/engines/skeleton_external.c +++ b/engines/skeleton_external.c @@ -3,7 +3,8 @@ * * 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 @@ -13,6 +14,7 @@ #include #include "../fio.h" +#include "../optgroup.h" /* * The core of the module is identical to the ones included with fio, @@ -20,6 +22,32 @@ * 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, @@ -140,4 +168,6 @@ struct ioengine_ops ioengine = { .cleanup = fio_skeleton_cleanup, .open_file = fio_skeleton_open, .close_file = fio_skeleton_close, + .options = options, + .option_struct_size = sizeof(struct fio_skeleton_options), }; diff --git a/fio.1 b/fio.1 index 5b63dfd7..97133dac 100644 --- a/fio.1 +++ b/fio.1 @@ -1572,7 +1572,9 @@ Read and write using device DAX to a persistent memory device (e.g., .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, -- 2.25.1