[PATCH 5/5] drm/amdkfd: Optimize out sdma doorbell array in kgd2kfd_shared_resources
Kuehling, Felix
Felix.Kuehling at amd.com
Fri Feb 8 22:06:01 UTC 2019
Some nit-picks inline. Looks good otherwise.
On 2019-02-05 3:31 p.m., Zhao, Yong wrote:
> We can directly calculate the sdma doorbell index in the process doorbell
> pages through the doorbell_index structure in amdgpu_device, so no need
> to cache them in kgd2kfd_shared_resources any more, resulting in more
> portable code.
What do you mean by "portable" here? Portable to what? Other
architectures? Kernels? GPUs?
>
> Change-Id: Ic657799856ed0256f36b01e502ef0cab263b1f49
> Signed-off-by: Yong Zhao <Yong.Zhao at amd.com>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c | 55 ++++++-------------
> .../drm/amd/amdkfd/kfd_device_queue_manager.c | 18 ++++--
> .../gpu/drm/amd/include/kgd_kfd_interface.h | 2 +-
> 3 files changed, 31 insertions(+), 44 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> index ee8527701731..e62c3703169a 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd.c
> @@ -131,7 +131,7 @@ static void amdgpu_doorbell_get_kfd_info(struct amdgpu_device *adev,
>
> void amdgpu_amdkfd_device_init(struct amdgpu_device *adev)
> {
> - int i, n;
> + int i;
> int last_valid_bit;
>
> if (adev->kfd.dev) {
> @@ -142,7 +142,9 @@ void amdgpu_amdkfd_device_init(struct amdgpu_device *adev)
> .gpuvm_size = min(adev->vm_manager.max_pfn
> << AMDGPU_GPU_PAGE_SHIFT,
> AMDGPU_GMC_HOLE_START),
> - .drm_render_minor = adev->ddev->render->index
> + .drm_render_minor = adev->ddev->render->index,
> + .sdma_doorbell_idx = adev->doorbell_index.sdma_engine,
> +
> };
>
> /* this is going to have a few of the MSBs set that we need to
> @@ -172,45 +174,22 @@ void amdgpu_amdkfd_device_init(struct amdgpu_device *adev)
> &gpu_resources.doorbell_aperture_size,
> &gpu_resources.doorbell_start_offset);
>
> - if (adev->asic_type < CHIP_VEGA10) {
> - kgd2kfd_device_init(adev->kfd.dev, &gpu_resources);
> - return;
> - }
> -
> - n = (adev->asic_type < CHIP_VEGA20) ? 2 : 8;
> -
> - for (i = 0; i < n; i += 2) {
> - /* On SOC15 the BIF is involved in routing
> - * doorbells using the low 12 bits of the
> - * address. Communicate the assignments to
> - * KFD. KFD uses two doorbell pages per
> - * process in case of 64-bit doorbells so we
> - * can use each doorbell assignment twice.
> + if (adev->asic_type >= CHIP_VEGA10) {
> + /* Because of the setting in registers like
> + * SDMA0_DOORBELL_RANGE etc., BIF statically uses the
> + * lower 12 bits of doorbell address for routing. In
> + * order to route the CP queue doorbells to CP engine,
> + * the doorbells allocated to CP queues have to be
> + * outside the range set for SDMA, VCN, and IH blocks
> + * Prior to SOC15, all queues use queue ID to
> + * determine doorbells.
> */
> - gpu_resources.sdma_doorbell[0][i] =
> - adev->doorbell_index.sdma_engine[0] + (i >> 1);
> - gpu_resources.sdma_doorbell[0][i+1] =
> - adev->doorbell_index.sdma_engine[0] + 0x200 + (i >> 1);
> - gpu_resources.sdma_doorbell[1][i] =
> - adev->doorbell_index.sdma_engine[1] + (i >> 1);
> - gpu_resources.sdma_doorbell[1][i+1] =
> - adev->doorbell_index.sdma_engine[1] + 0x200 + (i >> 1);
> + gpu_resources.reserved_doorbells_start =
> + adev->doorbell_index.sdma_engine[0];
> + gpu_resources.reserved_doorbells_end =
> + adev->doorbell_index.last_non_cp;
> }
>
> - /* Because of the setting in registers like
> - * SDMA0_DOORBELL_RANGE etc., BIF statically uses the
> - * lower 12 bits of doorbell address for routing. In
> - * order to route the CP queue doorbells to CP engine,
> - * the doorbells allocated to CP queues have to be
> - * outside the range set for SDMA, VCN, and IH blocks
> - * Prior to SOC15, all queues use queue ID to
> - * determine doorbells.
> - */
> - gpu_resources.reserved_doorbells_start =
> - adev->doorbell_index.sdma_engine[0];
> - gpu_resources.reserved_doorbells_end =
> - adev->doorbell_index.last_non_cp;
> -
> kgd2kfd_device_init(adev->kfd.dev, &gpu_resources);
> }
> }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> index 8372556b52eb..81280ce5aa27 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
> @@ -134,12 +134,20 @@ static int allocate_doorbell(struct qcm_process_device *qpd, struct queue *q)
> */
> q->doorbell_id = q->properties.queue_id;
> } else if (q->properties.type == KFD_QUEUE_TYPE_SDMA) {
> - /* For SDMA queues on SOC15, use static doorbell
> - * assignments based on the engine and queue.
> + /* For SDMA queues on SOC15 with 8-byte doorbell, use static
> + * doorbell assignments based on the engine and queue id.
> + * The doobell index distance between RLC (2*i) and (2*i+1)
> + * for a SDMA engine is 512.
> + * 512 8-byte doorbell distance (i.e. one page away) ensures
> + * that SDMA RLC (2*i+1) doorbell lies exactly in the doorbell
> + * OFFSET and SIZE set in register BIF_SDMA0_DOORBELL_RANGE.
> */
> - q->doorbell_id = dev->shared_resources.sdma_doorbell
> - [q->properties.sdma_engine_id]
> - [q->properties.sdma_queue_id];
> + unsigned int *idx_offset =
> + dev->shared_resources.sdma_doorbell_idx;
The type in struct amdgpu_doorbell_index is uint32_t. I'd prefer
matching the type of the pointer here.
> + q->doorbell_id = idx_offset[q->properties.sdma_engine_id]
> + + (q->properties.sdma_queue_id >> 1)
> + + (q->properties.sdma_queue_id % 2)
Be consistent with the use of bit-wise operations (x >> 1 and x & 1) or
division (x / 2 and x %2). Here you're mixing them. I prefer the
bit-wise operations for division and modulo with powers of two.
> + * KFD_QUEUE_DOORBELL_MIRROR_OFFSET;
> } else {
> /* For CP queues on SOC15 reserve a free doorbell ID */
> unsigned int found;
> diff --git a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
> index b1bf45419d93..3559170f6fb3 100644
> --- a/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
> +++ b/drivers/gpu/drm/amd/include/kgd_kfd_interface.h
> @@ -137,7 +137,7 @@ struct kgd2kfd_shared_resources {
> /* Bit n == 1 means Queue n is available for KFD */
> DECLARE_BITMAP(queue_bitmap, KGD_MAX_QUEUES);
>
> - unsigned int sdma_doorbell[2][8];
> + unsigned int *sdma_doorbell_idx;
The type in struct amdgpu_doorbell_index is uint32_t. I'd prefer
matching the type of the pointer here.
Regards,
Felix
>
> /* From SOC15 onwards, the doorbell indexes reserved for SDMA, IH,
> * and VCN
More information about the amd-gfx
mailing list