[RFC PATCH 1/3] drm/amdgpu: implement ring init_priority for compute ring

[Christian König]

Am 28.02.20 um 04:29 schrieb Luben Tuikov:
> On 2020-02-26 3:37 p.m., Nirmoy Das wrote:
>> init_priority will set second compute queue(gfx8 and gfx9) of a pipe to high priority
>> and 1st queue to normal priority.
>>
>> Signed-off-by: Nirmoy Das <nirmoy.das at amd.com>
>> ---
>>   drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h |  1 +
>>   drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c    | 14 ++++++++++++++
>>   drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c    | 13 +++++++++++++
>>   3 files changed, 28 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> index 24caff085d00..a109373b9fe8 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ring.h
>> @@ -170,6 +170,7 @@ struct amdgpu_ring_funcs {
>>   	/* priority functions */
>>   	void (*set_priority) (struct amdgpu_ring *ring,
>>   			      enum drm_sched_priority priority);
>> +	void (*init_priority) (struct amdgpu_ring *ring);
>>   	/* Try to soft recover the ring to make the fence signal */
>>   	void (*soft_recovery)(struct amdgpu_ring *ring, unsigned vmid);
>>   	int (*preempt_ib)(struct amdgpu_ring *ring);
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
>> index fa245973de12..14bab6e08bd6 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
>> @@ -6334,6 +6334,19 @@ static void gfx_v8_0_ring_set_priority_compute(struct amdgpu_ring *ring,
>>   	gfx_v8_0_pipe_reserve_resources(adev, ring, acquire);
>>   }
>>
>> +static void gfx_v8_0_ring_init_priority_compute(struct amdgpu_ring *ring)
> Why two verbs in this function: "init" and "compute"?

Compute is not a verb here but rather the description of the ring type.

> Certainly there is no need for "compute".
> Just call it
>
> gfx_blah_ring_priority_init()

I would call it gfx_*_init_compute_ring_priority().

>
> Putting the object first and the verb last, as is commonly done.

We need to make sure that we note that this is for the compute rings.

Regards,
Christian.

>
>> +{
>> +	/* set pipe 0 to normal priority and pipe 1 to high priority*/
>> +	if (ring->queue == 1) {
>> +		gfx_v8_0_hqd_set_priority(ring->adev, ring, true);
>> +		gfx_v8_0_ring_set_pipe_percent(ring, true);
>> +	} else {
>> +		gfx_v8_0_hqd_set_priority(ring->adev, ring, false);
>> +		gfx_v8_0_ring_set_pipe_percent(ring, false);
>> +	}
>> +
>> +}
> Again. Notice that the only difference between the two outcomes
> of the conditional is the last parameter to both.
>
> So you could write your code like this:
>
> gfx_v8_0_hqd_set_priority(ring->adev, ring, ring->queue == 1);
> gfx_v8_0_ring_set_pipe_percent(ring, ring->queue == 1);
>
> Further more if "priority" had to be variable value,
> I'd parameterize it in a map (i.e. array) and use
> a computed index to index the map in order to retrieve
> the variabled "priority". This eliminates if-conditionals.
>
> Note in general that we want less if-conditionals,
> in the execution path and more streamline execution.
>
>> +
>>   static void gfx_v8_0_ring_emit_fence_compute(struct amdgpu_ring *ring,
>>   					     u64 addr, u64 seq,
>>   					     unsigned flags)
>> @@ -6967,6 +6980,7 @@ static const struct amdgpu_ring_funcs gfx_v8_0_ring_funcs_compute = {
>>   	.insert_nop = amdgpu_ring_insert_nop,
>>   	.pad_ib = amdgpu_ring_generic_pad_ib,
>>   	.set_priority = gfx_v8_0_ring_set_priority_compute,
>> +	.init_priority = gfx_v8_0_ring_init_priority_compute,
>>   	.emit_wreg = gfx_v8_0_ring_emit_wreg,
>>   };
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>> index 1c7a16b91686..0c66743fb6f5 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
>> @@ -5143,6 +5143,18 @@ static void gfx_v9_0_ring_set_priority_compute(struct amdgpu_ring *ring,
>>   	gfx_v9_0_pipe_reserve_resources(adev, ring, acquire);
>>   }
>>
>> +static void gfx_v9_0_ring_init_priority_compute(struct amdgpu_ring *ring)
> Ditto for this name as per above.
>
>> +{
>> +	/* set pipe 0 to normal priority and pipe 1 to high priority*/
>> +	if (ring->queue == 1) {
>> +		gfx_v9_0_hqd_set_priority(ring->adev, ring, true);
>> +		gfx_v9_0_ring_set_pipe_percent(ring, true);
>> +	} else {
>> +		gfx_v9_0_hqd_set_priority(ring->adev, ring, false);
>> +		gfx_v9_0_ring_set_pipe_percent(ring, true);
>> +	}
>> +}
> Note how similar this is to the v8 above?
> Those could be made the same and he vX parameterized to
> the correct implementation.
>
> For instance, if you parameterize the "gfx_vX_0_hqd_set_priority()"
> and "gfx_vX_0_ring_set_pipe_percent()". Then your code becomes,
> like this pseudo-code:
>
> ring_init_set_priority(ring)
> {
>      map = ring->property[ring->version];
>
>      map->hqd_priority_set(ring->adev, ring, ring->queue == 1);
>      map->ring_pipe_percent_set(ring, ring->queue == 1);
> }
>
> Regards,
> Luben
>
>
>> +
>>   static void gfx_v9_0_ring_set_wptr_compute(struct amdgpu_ring *ring)
>>   {
>>   	struct amdgpu_device *adev = ring->adev;
>> @@ -6514,6 +6526,7 @@ static const struct amdgpu_ring_funcs gfx_v9_0_ring_funcs_compute = {
>>   	.insert_nop = amdgpu_ring_insert_nop,
>>   	.pad_ib = amdgpu_ring_generic_pad_ib,
>>   	.set_priority = gfx_v9_0_ring_set_priority_compute,
>> +	.init_priority = gfx_v9_0_ring_init_priority_compute,
>>   	.emit_wreg = gfx_v9_0_ring_emit_wreg,
>>   	.emit_reg_wait = gfx_v9_0_ring_emit_reg_wait,
>>   	.emit_reg_write_reg_wait = gfx_v9_0_ring_emit_reg_write_reg_wait,
>> --
>> 2.25.0
>>
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