engines/libblkio: Add option libblkio_force_enable_completion_eventfd

[fio.git] / engines / libblkio.c

diff --git a/engines/libblkio.c b/engines/libblkio.c
index 8a4828c394800873e47bbed2235caea0c139b93e..7f5dcf36bbc0a7145c6e9a00a14806eb9353d8d9 100644 (file)
--- a/engines/libblkio.c
+++ b/engines/libblkio.c
@@ -24,7 +24,7 @@
 struct fio_blkio_data {
        struct blkio *b;
        struct blkioq *q;
-       int completion_fd; /* -1 if not FIO_BLKIO_WAIT_MODE_EVENTFD */
+       int completion_fd; /* may be -1 if not FIO_BLKIO_WAIT_MODE_EVENTFD */
 
        bool has_mem_region; /* whether mem_region is valid */
        struct blkio_mem_region mem_region; /* only if allocated by libblkio */
@@ -50,6 +50,7 @@ struct fio_blkio_options {
        unsigned int vectored;
        unsigned int write_zeroes_on_trim;
        enum fio_blkio_wait_mode wait_mode;
+       unsigned int force_enable_completion_eventfd;
 };
 
 static struct fio_option options[] = {
@@ -132,6 +133,16 @@ static struct fio_option options[] = {
                .category = FIO_OPT_C_ENGINE,
                .group  = FIO_OPT_G_LIBBLKIO,
        },
+       {
+               .name   = "libblkio_force_enable_completion_eventfd",
+               .lname  = "Force enable the completion eventfd, even if unused",
+               .type   = FIO_OPT_STR_SET,
+               .off1   = offsetof(struct fio_blkio_options,
+                                  force_enable_completion_eventfd),
+               .help   = "This can impact performance",
+               .category = FIO_OPT_C_ENGINE,
+               .group  = FIO_OPT_G_LIBBLKIO,
+       },
        {
                .name = NULL,
        },
@@ -276,6 +287,11 @@ static int fio_blkio_setup(struct thread_data *td)
                return 1;
        }
 
+       if (options->hipri && options->force_enable_completion_eventfd) {
+               log_err("fio: option hipri is incompatible with option libblkio_force_enable_completion_eventfd\n");
+               return 1;
+       }
+
        if (fio_blkio_create_and_connect(td, &b) != 0)
                return 1;
 
@@ -342,7 +358,8 @@ static int fio_blkio_init(struct thread_data *td)
        else
                data->q = blkio_get_queue(data->b, 0);
 
-       if (options->wait_mode == FIO_BLKIO_WAIT_MODE_EVENTFD) {
+       if (options->wait_mode == FIO_BLKIO_WAIT_MODE_EVENTFD ||
+               options->force_enable_completion_eventfd) {
                /* enable completion fd and make it blocking */
                blkioq_set_completion_fd_enabled(data->q, true);
                data->completion_fd = blkioq_get_completion_fd(data->q);