[PATCH] drm/amdgpu: Enable tunneling on high-priority compute queues

[Christian König]

Well longer story short Alex and I have been digging up the 
documentation for this and as far as we can tell this isn't correct.

You need to do quite a bit more before you can turn on this feature. 
What userspace side do you refer to?

Regards,
Christian.

Am 08.12.23 um 09:19 schrieb Friedrich Vock:
> Friendly ping on this one.
> Userspace side got merged, so would be great to land this patch too :)
>
> On 02.12.23 01:17, Friedrich Vock wrote:
>> This improves latency if the GPU is already busy with other work.
>> This is useful for VR compositors that submit highly latency-sensitive
>> compositing work on high-priority compute queues while the GPU is busy
>> rendering the next frame.
>>
>> Userspace merge request:
>> https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26462
>>
>> Signed-off-by: Friedrich Vock <friedrich.vock at gmx.de>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu.h      |  1 +
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c | 10 ++++++----
>>   drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c   |  3 ++-
>>   drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c   |  3 ++-
>>   4 files changed, 11 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> index 9505dc8f9d69..4b923a156c4e 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
>> @@ -790,6 +790,7 @@ struct amdgpu_mqd_prop {
>>       uint64_t eop_gpu_addr;
>>       uint32_t hqd_pipe_priority;
>>       uint32_t hqd_queue_priority;
>> +    bool allow_tunneling;
>>       bool hqd_active;
>>   };
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c 
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> index 231d49132a56..4d98e8879be8 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.c
>> @@ -620,6 +620,10 @@ static void amdgpu_ring_to_mqd_prop(struct 
>> amdgpu_ring *ring,
>>                       struct amdgpu_mqd_prop *prop)
>>   {
>>       struct amdgpu_device *adev = ring->adev;
>> +    bool is_high_prio_compute = ring->funcs->type == 
>> AMDGPU_RING_TYPE_COMPUTE &&
>> + amdgpu_gfx_is_high_priority_compute_queue(adev, ring);
>> +    bool is_high_prio_gfx = ring->funcs->type == 
>> AMDGPU_RING_TYPE_GFX &&
>> + amdgpu_gfx_is_high_priority_graphics_queue(adev, ring);
>>
>>       memset(prop, 0, sizeof(*prop));
>>
>> @@ -637,10 +641,8 @@ static void amdgpu_ring_to_mqd_prop(struct 
>> amdgpu_ring *ring,
>>        */
>>       prop->hqd_active = ring->funcs->type == AMDGPU_RING_TYPE_KIQ;
>>
>> -    if ((ring->funcs->type == AMDGPU_RING_TYPE_COMPUTE &&
>> -         amdgpu_gfx_is_high_priority_compute_queue(adev, ring)) ||
>> -        (ring->funcs->type == AMDGPU_RING_TYPE_GFX &&
>> -         amdgpu_gfx_is_high_priority_graphics_queue(adev, ring))) {
>> +    prop->allow_tunneling = is_high_prio_compute;
>> +    if (is_high_prio_compute || is_high_prio_gfx) {
>>           prop->hqd_pipe_priority = AMDGPU_GFX_PIPE_PRIO_HIGH;
>>           prop->hqd_queue_priority = AMDGPU_GFX_QUEUE_PRIORITY_MAXIMUM;
>>       }
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c 
>> b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>> index c8a3bf01743f..73f6d7e72c73 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v10_0.c
>> @@ -6593,7 +6593,8 @@ static int gfx_v10_0_compute_mqd_init(struct 
>> amdgpu_device *adev, void *m,
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, ENDIAN_SWAP, 1);
>>   #endif
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, UNORD_DISPATCH, 0);
>> -    tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, TUNNEL_DISPATCH, 0);
>> +    tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, TUNNEL_DISPATCH,
>> +                prop->allow_tunneling);
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, PRIV_STATE, 1);
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, KMD_QUEUE, 1);
>>       mqd->cp_hqd_pq_control = tmp;
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c 
>> b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
>> index c659ef0f47ce..bdcf96df69e6 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v11_0.c
>> @@ -3847,7 +3847,8 @@ static int gfx_v11_0_compute_mqd_init(struct 
>> amdgpu_device *adev, void *m,
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, RPTR_BLOCK_SIZE,
>>                   (order_base_2(AMDGPU_GPU_PAGE_SIZE / 4) - 1));
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, UNORD_DISPATCH, 0);
>> -    tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, TUNNEL_DISPATCH, 0);
>> +    tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, TUNNEL_DISPATCH,
>> +                prop->allow_tunneling);
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, PRIV_STATE, 1);
>>       tmp = REG_SET_FIELD(tmp, CP_HQD_PQ_CONTROL, KMD_QUEUE, 1);
>>       mqd->cp_hqd_pq_control = tmp;
>> -- 
>> 2.43.0
>>