[PATCH 16/16] drm/amdkfd: use a high priority workqueue for IH work

[Oded Gabbay]

On Sat, Oct 21, 2017 at 3:23 AM, Felix Kuehling <Felix.Kuehling at amd.com> wrote:
> From: Andres Rodriguez <andres.rodriguez at amd.com>
>
> In systems under heavy load the IH work may experience significant
> scheduling delays.
>
> Under load + system workqueue:
>     Max Latency: 7.023695 ms
>     Avg Latency: 0.263994 ms
>
> Under load + high priority workqueue:
>     Max Latency: 1.162568 ms
>     Avg Latency: 0.163213 ms
>
> Further work is required to measure the impact of per-cpu settings on IH
> performance.
>
> Signed-off-by: Andres Rodriguez <andres.rodriguez at amd.com>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
> ---
>  drivers/gpu/drm/amd/amdkfd/kfd_device.c    | 2 +-
>  drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c | 3 ++-
>  drivers/gpu/drm/amd/amdkfd/kfd_priv.h      | 1 +
>  3 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device.c b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> index 46049f0..621a3b5 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device.c
> @@ -403,7 +403,7 @@ void kgd2kfd_interrupt(struct kfd_dev *kfd, const void *ih_ring_entry)
>         if (kfd->interrupts_active
>             && interrupt_is_wanted(kfd, ih_ring_entry)
>             && enqueue_ih_ring_entry(kfd, ih_ring_entry))
> -               schedule_work(&kfd->interrupt_work);
> +               queue_work(kfd->ih_wq, &kfd->interrupt_work);
>
>         spin_unlock(&kfd->interrupt_lock);
>  }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> index 9c08d46..035c351 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_interrupt.c
> @@ -61,6 +61,7 @@ int kfd_interrupt_init(struct kfd_dev *kfd)
>                 return r;
>         }
>
> +       kfd->ih_wq = alloc_workqueue("KFD IH", WQ_HIGHPRI, 1);
>         spin_lock_init(&kfd->interrupt_lock);
>
>         INIT_WORK(&kfd->interrupt_work, interrupt_wq);
> @@ -95,7 +96,7 @@ void kfd_interrupt_exit(struct kfd_dev *kfd)
>          * work-queue items that will access interrupt_ring. New work items
>          * can't be created because we stopped interrupt handling above.
>          */
> -       flush_work(&kfd->interrupt_work);
> +       flush_workqueue(kfd->ih_wq);
>
>         kfifo_free(&kfd->ih_fifo);
>  }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index e8d6c0e..bf29021 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -184,6 +184,7 @@ struct kfd_dev {
>
>         /* Interrupts */
>         struct kfifo ih_fifo;
> +       struct workqueue_struct *ih_wq;
>         struct work_struct interrupt_work;
>         spinlock_t interrupt_lock;
>
> --
> 2.7.4
>

This patch is:
Acked-by: Oded Gabbay <oded.gabbay at gmail.com>