On 2021/11/09 9:28, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@xxxxxxx>
>
> The default priority (which is either 0 or the value set by "prio" and
> "prioclass" options) is now saved in td->ioprio.
>
> The simplest thing is therefore to unconditionally set the async IO
> priority to td->ioprio fio_ioring_prep(), and let fio_ioring_prio_prep()
...to td->ioprio in fio_ioring_prep(), ...
> only handle the case where cmdprio_percentage/cmdprio_bssplit is enabled.
>
> Therefore, fio_ioring_prio_prep() doesn't need to care if prio/prioclass
> was enabled or not, we can simply think that fio_ioring_prio_prep()
> might "override" the default priority, whatever the default priority may
> be.
>
> Doing it this way also has the advantage that the prio_prep() function
> in io_uring will now look identical to the prio_prep() function in
> libaio.
>
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxx>
> ---
> engines/io_uring.c | 51 ++++++++++++++++++++++------------------------
> 1 file changed, 24 insertions(+), 27 deletions(-)
>
> diff --git a/engines/io_uring.c b/engines/io_uring.c
> index 27a4a678..8f3d6c39 100644
> --- a/engines/io_uring.c
> +++ b/engines/io_uring.c
> @@ -338,6 +338,18 @@ static int fio_ioring_prep(struct thread_data *td, struct io_u *io_u)
> sqe->rw_flags |= RWF_UNCACHED;
> if (o->nowait)
> sqe->rw_flags |= RWF_NOWAIT;
> +
> + /*
> + * Since io_uring can have a submission context (sqthread_poll)
> + * that is different from the process context, we cannot rely on
> + * the the IO priority set by ioprio_set()
You have two "the" here.
> + * (option prio/prioclass) to be inherited.
> + * td->ioprio will have the value of the "default prio", so set
> + * this unconditionally. This value might get overriden by
> + * fio_ioring_prio_prep() if cmdprio_percentage/cmdprio_bssplit
> + * is enabled.
...if the options cmdprio_percentage or cmdprio_bssplit are used.
> + */
> + sqe->ioprio = td->ioprio;
> sqe->off = io_u->offset;
> } else if (ddir_sync(io_u->ddir)) {
> sqe->ioprio = 0;
> @@ -456,29 +468,25 @@ static void fio_ioring_prio_prep(struct thread_data *td, struct io_u *io_u)
> ioprio_value(cmdprio->class[ddir], cmdprio->level[ddir]);
>
> if (p && rand_between(&td->prio_state, 0, 99) < p) {
> + io_u->ioprio = cmdprio_value;
> sqe->ioprio = cmdprio_value;
> if (!td->ioprio || cmdprio_value < td->ioprio) {
> /*
> * The async IO priority is higher (has a lower value)
> - * than the priority set by "prio" and "prioclass"
> - * options.
> - */
> - io_u->flags |= IO_U_F_HIGH_PRIO;
> - }
> - } else {
> - sqe->ioprio = td->ioprio;
> - if (cmdprio_value && td->ioprio && td->ioprio < cmdprio_value) {
> - /*
> - * The IO will be executed with the priority set by
> - * "prio" and "prioclass" options, and this priority
> - * is higher (has a lower value) than the async IO
> - * priority.
> + * than the default priority (which is either 0 or the
> + * value set by "prio" and "prioclass" options).
> */
> io_u->flags |= IO_U_F_HIGH_PRIO;
> }
> + } else if (td->ioprio && td->ioprio < cmdprio_value) {
> + /*
> + * The IO will be executed with the default priority (which is
> + * either 0 or the value set by "prio" and "prioclass options),
> + * and this priority is higher (has a lower value) than the
> + * async IO priority.
> + */
> + io_u->flags |= IO_U_F_HIGH_PRIO;
> }
> -
> - io_u->ioprio = sqe->ioprio;
> }
>
> static enum fio_q_status fio_ioring_queue(struct thread_data *td,
> @@ -820,7 +828,6 @@ static int fio_ioring_init(struct thread_data *td)
> struct ioring_options *o = td->eo;
> struct ioring_data *ld;
> struct cmdprio *cmdprio = &o->cmdprio;
> - bool has_cmdprio = false;
> int ret;
>
> /* sqthread submission requires registered files */
> @@ -845,22 +852,12 @@ static int fio_ioring_init(struct thread_data *td)
>
> td->io_ops_data = ld;
>
> - ret = fio_cmdprio_init(td, cmdprio, &has_cmdprio);
> + ret = fio_cmdprio_init(td, cmdprio, &ld->use_cmdprio);
> if (ret) {
> td_verror(td, EINVAL, "fio_ioring_init");
> return 1;
> }
>
> - /*
> - * Since io_uring can have a submission context (sqthread_poll) that is
> - * different from the process context, we cannot rely on the the IO
> - * priority set by ioprio_set() (option prio/prioclass) to be inherited.
> - * Therefore, we set the sqe->ioprio field when prio/prioclass is used.
> - */
> - ld->use_cmdprio = has_cmdprio ||
> - fio_option_is_set(&td->o, ioprio_class) ||
> - fio_option_is_set(&td->o, ioprio);
> -
> return 0;
> }
>
>
--
Damien Le Moal
Western Digital Research
