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On 2018年08月02日 14:01, Nayan Deshmukh
wrote:
Hi David,
Another big question:
I agree the general idea is good
to balance scheduler load for same ring family.
But, when same entity job run on
different scheduler, that means the later job could
be completed ahead of front, Right?
Really good question. To avoid this senario we do not
move an entity which already has a job in the hardware
queue. We only move entities whose last_scheduled fence
has been signalled which means that the last submitted job
of this entity has finished executing.
Good handling I missed when reviewing them.
Cheers,
David Zhou
Moving an entity which already has a job in the
hardware queue will hinder the dependency optimization
that we are using and hence will not anyway lead to a
better performance. I have talked about the issue in more
detail here [1]. Please let me know if you have any more
doubts regarding this.
Cheers,
That will break fence design,
later fence must be signaled after front fence in
same fence context.
Anything I missed?
Regards,
David Zhou
From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx>
On Behalf Of Nayan Deshmukh
Sent: Thursday, August 02, 2018 12:07 AM
To: Grodzovsky, Andrey <Andrey.Grodzovsky@xxxxxxx>
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx;
Maling list - DRI developers <dri-devel@xxxxxxxxxxxxxxxxxxxxx>;
Koenig, Christian <Christian.Koenig@xxxxxxx>
Subject: Re: [PATCH 3/4] drm/scheduler: add
new function to get least loaded sched v2
Clarification
question - if the run queues belong to
different
schedulers they effectively point to different
rings,
it means we allow to move (reschedule) a
drm_sched_entity from one ring
to another - i assume that the idea int the
first place, that
you have a set of HW rings and you can utilize
any of them for your jobs
(like compute rings). Correct ?
Andrey
On 08/01/2018 04:20 AM, Nayan Deshmukh wrote:
> The function selects the run queue from the
rq_list with the
> least load. The load is decided by the
number of jobs in a
> scheduler.
>
> v2: avoid using atomic read twice
consecutively, instead store
> it locally
>
> Signed-off-by: Nayan Deshmukh <nayan26deshmukh@xxxxxxxxx>
> ---
> drivers/gpu/drm/scheduler/gpu_scheduler.c
| 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git
a/drivers/gpu/drm/scheduler/gpu_scheduler.c
b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> index 375f6f7f6a93..fb4e542660b0 100644
> ---
a/drivers/gpu/drm/scheduler/gpu_scheduler.c
> +++
b/drivers/gpu/drm/scheduler/gpu_scheduler.c
> @@ -255,6 +255,31 @@ static bool
drm_sched_entity_is_ready(struct
drm_sched_entity *entity)
> return true;
> }
>
> +/**
> + * drm_sched_entity_get_free_sched - Get
the rq from rq_list with least load
> + *
> + * @entity: scheduler entity
> + *
> + * Return the pointer to the rq with least
load.
> + */
> +static struct drm_sched_rq *
> +drm_sched_entity_get_free_sched(struct
drm_sched_entity *entity)
> +{
> + struct drm_sched_rq *rq = NULL;
> + unsigned int min_jobs = UINT_MAX,
num_jobs;
> + int i;
> +
> + for (i = 0; i <
entity->num_rq_list; ++i) {
> + num_jobs =
atomic_read(&entity->rq_list[i]->sched->num_jobs);
> + if (num_jobs < min_jobs) {
> + min_jobs = num_jobs;
> + rq =
entity->rq_list[i];
> + }
> + }
> +
> + return rq;
> +}
> +
> static void
drm_sched_entity_kill_jobs_cb(struct dma_fence
*f,
> struct
dma_fence_cb *cb)
> {
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