On Fri, Feb 23, 2024 at 4:48 AM Pierre-Eric Pelloux-Prayer
<pierre-eric.pelloux-prayer@xxxxxxx> wrote:
>
> Using the ring_muxer without preemption adds overhead for no
> reason since mcbp cannot be triggered.
>
> Moving back to a single queue in this case also helps when
> high priority app are used: in this case the gpu_scheduler
> priority handling will work as expected - much better than
> ring_muxer with its 2 independant schedulers competing for
> the same hardware queue.
>
> This change requires moving amdgpu_device_set_mcbp above
> amdgpu_device_ip_early_init because we use adev->gfx.mcbp.
>
> Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@xxxxxxx>
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
> ---
> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 4 ++--
> drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c | 21 ++++++++++++---------
> 2 files changed, 14 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> index d534e192e260..40516d24026c 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
> @@ -4054,13 +4054,13 @@ int amdgpu_device_init(struct amdgpu_device *adev,
> return r;
> }
>
> + amdgpu_device_set_mcbp(adev);
> +
> /* early init functions */
> r = amdgpu_device_ip_early_init(adev);
> if (r)
> return r;
>
> - amdgpu_device_set_mcbp(adev);
> -
> /* Get rid of things like offb */
> r = drm_aperture_remove_conflicting_pci_framebuffers(adev->pdev, &amdgpu_kms_driver);
> if (r)
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
> index 169d45268ef6..f682f830f7f6 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v9_0.c
> @@ -2080,7 +2080,7 @@ static int gfx_v9_0_sw_init(void *handle)
> ring->doorbell_index = adev->doorbell_index.gfx_ring0 << 1;
>
> /* disable scheduler on the real ring */
> - ring->no_scheduler = true;
> + ring->no_scheduler = adev->gfx.mcbp;
> ring->vm_hub = AMDGPU_GFXHUB(0);
> r = amdgpu_ring_init(adev, ring, 1024, &adev->gfx.eop_irq,
> AMDGPU_CP_IRQ_GFX_ME0_PIPE0_EOP,
> @@ -2090,7 +2090,7 @@ static int gfx_v9_0_sw_init(void *handle)
> }
>
> /* set up the software rings */
> - if (adev->gfx.num_gfx_rings) {
> + if (adev->gfx.mcbp && adev->gfx.num_gfx_rings) {
> for (i = 0; i < GFX9_NUM_SW_GFX_RINGS; i++) {
> ring = &adev->gfx.sw_gfx_ring[i];
> ring->ring_obj = NULL;
> @@ -2181,7 +2181,7 @@ static int gfx_v9_0_sw_fini(void *handle)
> int i;
> struct amdgpu_device *adev = (struct amdgpu_device *)handle;
>
> - if (adev->gfx.num_gfx_rings) {
> + if (adev->gfx.mcbp && adev->gfx.num_gfx_rings) {
> for (i = 0; i < GFX9_NUM_SW_GFX_RINGS; i++)
> amdgpu_ring_fini(&adev->gfx.sw_gfx_ring[i]);
> amdgpu_ring_mux_fini(&adev->gfx.muxer);
> @@ -5910,11 +5910,14 @@ static int gfx_v9_0_eop_irq(struct amdgpu_device *adev,
>
> switch (me_id) {
> case 0:
> - if (adev->gfx.num_gfx_rings &&
> - !amdgpu_mcbp_handle_trailing_fence_irq(&adev->gfx.muxer)) {
> - /* Fence signals are handled on the software rings*/
> - for (i = 0; i < GFX9_NUM_SW_GFX_RINGS; i++)
> - amdgpu_fence_process(&adev->gfx.sw_gfx_ring[i]);
> + if (adev->gfx.num_gfx_rings) {
> + if (!adev->gfx.mcbp) {
> + amdgpu_fence_process(&adev->gfx.gfx_ring[0]);
> + } else if (!amdgpu_mcbp_handle_trailing_fence_irq(&adev->gfx.muxer)) {
> + /* Fence signals are handled on the software rings*/
> + for (i = 0; i < GFX9_NUM_SW_GFX_RINGS; i++)
> + amdgpu_fence_process(&adev->gfx.sw_gfx_ring[i]);
> + }
> }
> break;
> case 1:
> @@ -7051,7 +7054,7 @@ static void gfx_v9_0_set_ring_funcs(struct amdgpu_device *adev)
> for (i = 0; i < adev->gfx.num_gfx_rings; i++)
> adev->gfx.gfx_ring[i].funcs = &gfx_v9_0_ring_funcs_gfx;
>
> - if (adev->gfx.num_gfx_rings) {
> + if (adev->gfx.mcbp && adev->gfx.num_gfx_rings) {
> for (i = 0; i < GFX9_NUM_SW_GFX_RINGS; i++)
> adev->gfx.sw_gfx_ring[i].funcs = &gfx_v9_0_sw_ring_funcs_gfx;
> }
> --
> 2.40.1
>
