diff mbox series

drm/i915/gem: Don't try to map and fence 8K/bigjoiner scanout buffers

Message ID 20211026063811.1375040-1-vivek.kasireddy@intel.com (mailing list archive)
State New, archived
Headers show
Series drm/i915/gem: Don't try to map and fence 8K/bigjoiner scanout buffers | expand

Commit Message

Kasireddy, Vivek Oct. 26, 2021, 6:38 a.m. UTC
On platforms capable of allowing 8K (7680 x 4320) modes, pinning 2 or
more framebuffers/scanout buffers results in only one that is mappable/
fenceable. Therefore, pageflipping between these 2 FBs where only one
is mappable/fenceable creates latencies large enough to miss alternate
vblanks thereby producing less optimal framerate.

This mainly happens because when i915_gem_object_pin_to_display_plane()
is called to pin one of the FB objs, the associated vma is identified
as misplaced and therefore i915_vma_unbind() is called which unbinds and
evicts it. This misplaced vma gets subseqently pinned only when
i915_gem_object_ggtt_pin_ww() is called without the mappable flag. This
results in a latency of ~10ms and happens every other vblank/repaint cycle.

Testcase:
Running Weston and weston-simple-egl on an Alderlake_S (ADLS) platform
with a 8K@60 mode results in only ~40 FPS. Since upstream Weston submits
a frame ~7ms before the next vblank, the latencies seen between atomic
commit and flip event is 7, 24 (7 + 16.66), 7, 24..... suggesting that
it misses the vblank every other frame.

Here is the ftrace snippet that shows the source of the ~10ms latency:
              i915_gem_object_pin_to_display_plane() {
0.102 us   |    i915_gem_object_set_cache_level();
                i915_gem_object_ggtt_pin_ww() {
0.390 us   |      i915_vma_instance();
0.178 us   |      i915_vma_misplaced();
                  i915_vma_unbind() {
                  __i915_active_wait() {
0.082 us   |        i915_active_acquire_if_busy();
0.475 us   |      }
                  intel_runtime_pm_get() {
0.087 us   |        intel_runtime_pm_acquire();
0.259 us   |      }
                  __i915_active_wait() {
0.085 us   |        i915_active_acquire_if_busy();
0.240 us   |      }
                  __i915_vma_evict() {
                    ggtt_unbind_vma() {
                      gen8_ggtt_clear_range() {
10507.255 us |        }
10507.689 us |      }
10508.516 us |   }

Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Manasi Navare <manasi.d.navare@intel.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 drivers/gpu/drm/i915/display/intel_fb_pin.c  | 11 +++++++++--
 drivers/gpu/drm/i915/display/intel_overlay.c | 11 ++++++++---
 drivers/gpu/drm/i915/gem/i915_gem_domain.c   |  6 ++++--
 drivers/gpu/drm/i915/gem/i915_gem_object.h   |  3 ++-
 4 files changed, 23 insertions(+), 8 deletions(-)

Comments

Ville Syrjälä Oct. 26, 2021, 9:07 a.m. UTC | #1
On Mon, Oct 25, 2021 at 11:38:11PM -0700, Vivek Kasireddy wrote:
> On platforms capable of allowing 8K (7680 x 4320) modes, pinning 2 or
> more framebuffers/scanout buffers results in only one that is mappable/
> fenceable. Therefore, pageflipping between these 2 FBs where only one
> is mappable/fenceable creates latencies large enough to miss alternate
> vblanks thereby producing less optimal framerate.
> 
> This mainly happens because when i915_gem_object_pin_to_display_plane()
> is called to pin one of the FB objs, the associated vma is identified
> as misplaced and therefore i915_vma_unbind() is called which unbinds and
> evicts it. This misplaced vma gets subseqently pinned only when
> i915_gem_object_ggtt_pin_ww() is called without the mappable flag. This
> results in a latency of ~10ms and happens every other vblank/repaint cycle.
> 
> Testcase:
> Running Weston and weston-simple-egl on an Alderlake_S (ADLS) platform
> with a 8K@60 mode results in only ~40 FPS. Since upstream Weston submits
> a frame ~7ms before the next vblank, the latencies seen between atomic
> commit and flip event is 7, 24 (7 + 16.66), 7, 24..... suggesting that
> it misses the vblank every other frame.
> 
> Here is the ftrace snippet that shows the source of the ~10ms latency:
>               i915_gem_object_pin_to_display_plane() {
> 0.102 us   |    i915_gem_object_set_cache_level();
>                 i915_gem_object_ggtt_pin_ww() {
> 0.390 us   |      i915_vma_instance();
> 0.178 us   |      i915_vma_misplaced();
>                   i915_vma_unbind() {
>                   __i915_active_wait() {
> 0.082 us   |        i915_active_acquire_if_busy();
> 0.475 us   |      }
>                   intel_runtime_pm_get() {
> 0.087 us   |        intel_runtime_pm_acquire();
> 0.259 us   |      }
>                   __i915_active_wait() {
> 0.085 us   |        i915_active_acquire_if_busy();
> 0.240 us   |      }
>                   __i915_vma_evict() {
>                     ggtt_unbind_vma() {
>                       gen8_ggtt_clear_range() {
> 10507.255 us |        }
> 10507.689 us |      }
> 10508.516 us |   }
> 
> Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_fb_pin.c  | 11 +++++++++--
>  drivers/gpu/drm/i915/display/intel_overlay.c | 11 ++++++++---
>  drivers/gpu/drm/i915/gem/i915_gem_domain.c   |  6 ++++--
>  drivers/gpu/drm/i915/gem/i915_gem_object.h   |  3 ++-
>  4 files changed, 23 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> index 3f77f3013584..53c156d9a9f9 100644
> --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> @@ -144,7 +144,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
>  
>  	if (!ret) {
>  		vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment,
> -							   view, pinctl);
> +							   view, pinctl, uses_fence);
>  		if (IS_ERR(vma)) {
>  			ret = PTR_ERR(vma);
>  			goto err_unpin;
> @@ -218,9 +218,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
>  		INTEL_INFO(dev_priv)->display.cursor_needs_physical;
>  
>  	if (!intel_fb_uses_dpt(fb)) {
> +		struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc);
> +		struct intel_crtc_state *crtc_state =
> +					to_intel_crtc_state(crtc->base.state);
> +		bool uses_fence = intel_plane_uses_fence(plane_state);
> +		bool is_bigjoiner = crtc_state->bigjoiner ||
> +				    crtc_state->bigjoiner_slave;

Bigjoiner is just an implementation detail. It is not the cause of any
of this.

> +
>  		vma = intel_pin_and_fence_fb_obj(fb, phys_cursor,
>  						 &plane_state->view.gtt,
> -						 intel_plane_uses_fence(plane_state),
> +						 uses_fence && !is_bigjoiner,
>  						 &plane_state->flags);
>  		if (IS_ERR(vma))
>  			return PTR_ERR(vma);
> diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
> index 7e3f5c6ca484..e9563b40b911 100644
> --- a/drivers/gpu/drm/i915/display/intel_overlay.c
> +++ b/drivers/gpu/drm/i915/display/intel_overlay.c
> @@ -755,10 +755,14 @@ static u32 overlay_cmd_reg(struct drm_intel_overlay_put_image *params)
>  	return cmd;
>  }
>  
> -static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo)
> +static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo,
> +					     struct intel_overlay *overlay)
>  {
>  	struct i915_gem_ww_ctx ww;
>  	struct i915_vma *vma;
> +	const struct intel_plane_state *plane_state =
> +		to_intel_plane_state(overlay->crtc->base.primary->state);
> +	bool uses_fence = intel_plane_uses_fence(plane_state);
>  	int ret;
>  
>  	i915_gem_ww_ctx_init(&ww, true);
> @@ -766,7 +770,8 @@ static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo)
>  	ret = i915_gem_object_lock(new_bo, &ww);
>  	if (!ret) {
>  		vma = i915_gem_object_pin_to_display_plane(new_bo, &ww, 0,
> -							   NULL, PIN_MAPPABLE);
> +							   NULL, PIN_MAPPABLE,
> +							   uses_fence);
>  		ret = PTR_ERR_OR_ZERO(vma);
>  	}
>  	if (ret == -EDEADLK) {
> @@ -802,7 +807,7 @@ static int intel_overlay_do_put_image(struct intel_overlay *overlay,
>  
>  	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
>  
> -	vma = intel_overlay_pin_fb(new_bo);
> +	vma = intel_overlay_pin_fb(new_bo, overlay);
>  	if (IS_ERR(vma)) {
>  		ret = PTR_ERR(vma);
>  		goto out_pin_section;
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> index b684a62bf3b0..b9108f13cc49 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> @@ -375,7 +375,8 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
>  				     struct i915_gem_ww_ctx *ww,
>  				     u32 alignment,
>  				     const struct i915_ggtt_view *view,
> -				     unsigned int flags)
> +				     unsigned int flags,
> +				     bool uses_fence)
>  {
>  	struct drm_i915_private *i915 = to_i915(obj->base.dev);
>  	struct i915_vma *vma;
> @@ -411,7 +412,8 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
>  	 */
>  	vma = ERR_PTR(-ENOSPC);
>  	if ((flags & PIN_MAPPABLE) == 0 &&
> -	    (!view || view->type == I915_GGTT_VIEW_NORMAL))
> +	    (!view || view->type == I915_GGTT_VIEW_NORMAL) &&
> +	    uses_fence)
>  		vma = i915_gem_object_ggtt_pin_ww(obj, ww, view, 0, alignment,
>  						  flags | PIN_MAPPABLE |
>  						  PIN_NONBLOCK);
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index a5479ac7a4ad..e83564fa57ca 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -534,7 +534,8 @@ i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
>  				     struct i915_gem_ww_ctx *ww,
>  				     u32 alignment,
>  				     const struct i915_ggtt_view *view,
> -				     unsigned int flags);
> +				     unsigned int flags,
> +				     bool uses_fence);
>  
>  void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj);
>  void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj);
> -- 
> 2.31.1
Kasireddy, Vivek Oct. 27, 2021, 6:41 a.m. UTC | #2
Hi Ville,

> 
> On Mon, Oct 25, 2021 at 11:38:11PM -0700, Vivek Kasireddy wrote:
> > On platforms capable of allowing 8K (7680 x 4320) modes, pinning 2 or
> > more framebuffers/scanout buffers results in only one that is mappable/
> > fenceable. Therefore, pageflipping between these 2 FBs where only one
> > is mappable/fenceable creates latencies large enough to miss alternate
> > vblanks thereby producing less optimal framerate.
> >
> > This mainly happens because when i915_gem_object_pin_to_display_plane()
> > is called to pin one of the FB objs, the associated vma is identified
> > as misplaced and therefore i915_vma_unbind() is called which unbinds and
> > evicts it. This misplaced vma gets subseqently pinned only when
> > i915_gem_object_ggtt_pin_ww() is called without the mappable flag. This
> > results in a latency of ~10ms and happens every other vblank/repaint cycle.
> >
> > Testcase:
> > Running Weston and weston-simple-egl on an Alderlake_S (ADLS) platform
> > with a 8K@60 mode results in only ~40 FPS. Since upstream Weston submits
> > a frame ~7ms before the next vblank, the latencies seen between atomic
> > commit and flip event is 7, 24 (7 + 16.66), 7, 24..... suggesting that
> > it misses the vblank every other frame.
> >
> > Here is the ftrace snippet that shows the source of the ~10ms latency:
> >               i915_gem_object_pin_to_display_plane() {
> > 0.102 us   |    i915_gem_object_set_cache_level();
> >                 i915_gem_object_ggtt_pin_ww() {
> > 0.390 us   |      i915_vma_instance();
> > 0.178 us   |      i915_vma_misplaced();
> >                   i915_vma_unbind() {
> >                   __i915_active_wait() {
> > 0.082 us   |        i915_active_acquire_if_busy();
> > 0.475 us   |      }
> >                   intel_runtime_pm_get() {
> > 0.087 us   |        intel_runtime_pm_acquire();
> > 0.259 us   |      }
> >                   __i915_active_wait() {
> > 0.085 us   |        i915_active_acquire_if_busy();
> > 0.240 us   |      }
> >                   __i915_vma_evict() {
> >                     ggtt_unbind_vma() {
> >                       gen8_ggtt_clear_range() {
> > 10507.255 us |        }
> > 10507.689 us |      }
> > 10508.516 us |   }
> >
> > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_fb_pin.c  | 11 +++++++++--
> >  drivers/gpu/drm/i915/display/intel_overlay.c | 11 ++++++++---
> >  drivers/gpu/drm/i915/gem/i915_gem_domain.c   |  6 ++++--
> >  drivers/gpu/drm/i915/gem/i915_gem_object.h   |  3 ++-
> >  4 files changed, 23 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > index 3f77f3013584..53c156d9a9f9 100644
> > --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > @@ -144,7 +144,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
> >
> >  	if (!ret) {
> >  		vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment,
> > -							   view, pinctl);
> > +							   view, pinctl, uses_fence);
> >  		if (IS_ERR(vma)) {
> >  			ret = PTR_ERR(vma);
> >  			goto err_unpin;
> > @@ -218,9 +218,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
> >  		INTEL_INFO(dev_priv)->display.cursor_needs_physical;
> >
> >  	if (!intel_fb_uses_dpt(fb)) {
> > +		struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc);
> > +		struct intel_crtc_state *crtc_state =
> > +					to_intel_crtc_state(crtc->base.state);
> > +		bool uses_fence = intel_plane_uses_fence(plane_state);
> > +		bool is_bigjoiner = crtc_state->bigjoiner ||
> > +				    crtc_state->bigjoiner_slave;
> 
> Bigjoiner is just an implementation detail. It is not the cause of any
> of this.
[Kasireddy, Vivek] Right, bigjoiner/8K is just exposing the underlying issue; which is
that sometimes, large objects/scanout buffers that fail range overflow checks and thus
are not mappable/fenceable keep getting evicted and reinserted leading to latencies. 
I guess I could mark an object/vma as permanently un-mappable/un-fenceable and try
not to map it subsequently but this would result in one scanout buffer that is mappable
but others that are not. Would this be acceptable -- assuming we are pageflipping
between multiple FBs?
Any ideas on solving this issue cleanly?

Thanks,
Vivek
 
> 
> > +
> >  		vma = intel_pin_and_fence_fb_obj(fb, phys_cursor,
> >  						 &plane_state->view.gtt,
> > -						 intel_plane_uses_fence(plane_state),
> > +						 uses_fence && !is_bigjoiner,
> >  						 &plane_state->flags);
> >  		if (IS_ERR(vma))
> >  			return PTR_ERR(vma);
> > diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c
> b/drivers/gpu/drm/i915/display/intel_overlay.c
> > index 7e3f5c6ca484..e9563b40b911 100644
> > --- a/drivers/gpu/drm/i915/display/intel_overlay.c
> > +++ b/drivers/gpu/drm/i915/display/intel_overlay.c
> > @@ -755,10 +755,14 @@ static u32 overlay_cmd_reg(struct
> drm_intel_overlay_put_image *params)
> >  	return cmd;
> >  }
> >
> > -static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo)
> > +static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo,
> > +					     struct intel_overlay *overlay)
> >  {
> >  	struct i915_gem_ww_ctx ww;
> >  	struct i915_vma *vma;
> > +	const struct intel_plane_state *plane_state =
> > +		to_intel_plane_state(overlay->crtc->base.primary->state);
> > +	bool uses_fence = intel_plane_uses_fence(plane_state);
> >  	int ret;
> >
> >  	i915_gem_ww_ctx_init(&ww, true);
> > @@ -766,7 +770,8 @@ static struct i915_vma *intel_overlay_pin_fb(struct
> drm_i915_gem_object *new_bo)
> >  	ret = i915_gem_object_lock(new_bo, &ww);
> >  	if (!ret) {
> >  		vma = i915_gem_object_pin_to_display_plane(new_bo, &ww, 0,
> > -							   NULL, PIN_MAPPABLE);
> > +							   NULL, PIN_MAPPABLE,
> > +							   uses_fence);
> >  		ret = PTR_ERR_OR_ZERO(vma);
> >  	}
> >  	if (ret == -EDEADLK) {
> > @@ -802,7 +807,7 @@ static int intel_overlay_do_put_image(struct intel_overlay
> *overlay,
> >
> >  	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
> >
> > -	vma = intel_overlay_pin_fb(new_bo);
> > +	vma = intel_overlay_pin_fb(new_bo, overlay);
> >  	if (IS_ERR(vma)) {
> >  		ret = PTR_ERR(vma);
> >  		goto out_pin_section;
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> > index b684a62bf3b0..b9108f13cc49 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
> > @@ -375,7 +375,8 @@ i915_gem_object_pin_to_display_plane(struct
> drm_i915_gem_object *obj,
> >  				     struct i915_gem_ww_ctx *ww,
> >  				     u32 alignment,
> >  				     const struct i915_ggtt_view *view,
> > -				     unsigned int flags)
> > +				     unsigned int flags,
> > +				     bool uses_fence)
> >  {
> >  	struct drm_i915_private *i915 = to_i915(obj->base.dev);
> >  	struct i915_vma *vma;
> > @@ -411,7 +412,8 @@ i915_gem_object_pin_to_display_plane(struct
> drm_i915_gem_object *obj,
> >  	 */
> >  	vma = ERR_PTR(-ENOSPC);
> >  	if ((flags & PIN_MAPPABLE) == 0 &&
> > -	    (!view || view->type == I915_GGTT_VIEW_NORMAL))
> > +	    (!view || view->type == I915_GGTT_VIEW_NORMAL) &&
> > +	    uses_fence)
> >  		vma = i915_gem_object_ggtt_pin_ww(obj, ww, view, 0, alignment,
> >  						  flags | PIN_MAPPABLE |
> >  						  PIN_NONBLOCK);
> > diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > index a5479ac7a4ad..e83564fa57ca 100644
> > --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> > @@ -534,7 +534,8 @@ i915_gem_object_pin_to_display_plane(struct
> drm_i915_gem_object *obj,
> >  				     struct i915_gem_ww_ctx *ww,
> >  				     u32 alignment,
> >  				     const struct i915_ggtt_view *view,
> > -				     unsigned int flags);
> > +				     unsigned int flags,
> > +				     bool uses_fence);
> >
> >  void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj);
> >  void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj);
> > --
> > 2.31.1
> 
> --
> Ville Syrjälä
> Intel
Ville Syrjälä Oct. 27, 2021, 8:27 a.m. UTC | #3
On Wed, Oct 27, 2021 at 06:41:25AM +0000, Kasireddy, Vivek wrote:
> Hi Ville,
> 
> > 
> > On Mon, Oct 25, 2021 at 11:38:11PM -0700, Vivek Kasireddy wrote:
> > > On platforms capable of allowing 8K (7680 x 4320) modes, pinning 2 or
> > > more framebuffers/scanout buffers results in only one that is mappable/
> > > fenceable. Therefore, pageflipping between these 2 FBs where only one
> > > is mappable/fenceable creates latencies large enough to miss alternate
> > > vblanks thereby producing less optimal framerate.
> > >
> > > This mainly happens because when i915_gem_object_pin_to_display_plane()
> > > is called to pin one of the FB objs, the associated vma is identified
> > > as misplaced and therefore i915_vma_unbind() is called which unbinds and
> > > evicts it. This misplaced vma gets subseqently pinned only when
> > > i915_gem_object_ggtt_pin_ww() is called without the mappable flag. This
> > > results in a latency of ~10ms and happens every other vblank/repaint cycle.
> > >
> > > Testcase:
> > > Running Weston and weston-simple-egl on an Alderlake_S (ADLS) platform
> > > with a 8K@60 mode results in only ~40 FPS. Since upstream Weston submits
> > > a frame ~7ms before the next vblank, the latencies seen between atomic
> > > commit and flip event is 7, 24 (7 + 16.66), 7, 24..... suggesting that
> > > it misses the vblank every other frame.
> > >
> > > Here is the ftrace snippet that shows the source of the ~10ms latency:
> > >               i915_gem_object_pin_to_display_plane() {
> > > 0.102 us   |    i915_gem_object_set_cache_level();
> > >                 i915_gem_object_ggtt_pin_ww() {
> > > 0.390 us   |      i915_vma_instance();
> > > 0.178 us   |      i915_vma_misplaced();
> > >                   i915_vma_unbind() {
> > >                   __i915_active_wait() {
> > > 0.082 us   |        i915_active_acquire_if_busy();
> > > 0.475 us   |      }
> > >                   intel_runtime_pm_get() {
> > > 0.087 us   |        intel_runtime_pm_acquire();
> > > 0.259 us   |      }
> > >                   __i915_active_wait() {
> > > 0.085 us   |        i915_active_acquire_if_busy();
> > > 0.240 us   |      }
> > >                   __i915_vma_evict() {
> > >                     ggtt_unbind_vma() {
> > >                       gen8_ggtt_clear_range() {
> > > 10507.255 us |        }
> > > 10507.689 us |      }
> > > 10508.516 us |   }
> > >
> > > Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> > > Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> > > Cc: Manasi Navare <manasi.d.navare@intel.com>
> > > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_fb_pin.c  | 11 +++++++++--
> > >  drivers/gpu/drm/i915/display/intel_overlay.c | 11 ++++++++---
> > >  drivers/gpu/drm/i915/gem/i915_gem_domain.c   |  6 ++++--
> > >  drivers/gpu/drm/i915/gem/i915_gem_object.h   |  3 ++-
> > >  4 files changed, 23 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > > index 3f77f3013584..53c156d9a9f9 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
> > > @@ -144,7 +144,7 @@ intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
> > >
> > >  	if (!ret) {
> > >  		vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment,
> > > -							   view, pinctl);
> > > +							   view, pinctl, uses_fence);
> > >  		if (IS_ERR(vma)) {
> > >  			ret = PTR_ERR(vma);
> > >  			goto err_unpin;
> > > @@ -218,9 +218,16 @@ int intel_plane_pin_fb(struct intel_plane_state *plane_state)
> > >  		INTEL_INFO(dev_priv)->display.cursor_needs_physical;
> > >
> > >  	if (!intel_fb_uses_dpt(fb)) {
> > > +		struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc);
> > > +		struct intel_crtc_state *crtc_state =
> > > +					to_intel_crtc_state(crtc->base.state);
> > > +		bool uses_fence = intel_plane_uses_fence(plane_state);
> > > +		bool is_bigjoiner = crtc_state->bigjoiner ||
> > > +				    crtc_state->bigjoiner_slave;
> > 
> > Bigjoiner is just an implementation detail. It is not the cause of any
> > of this.
> [Kasireddy, Vivek] Right, bigjoiner/8K is just exposing the underlying issue; which is
> that sometimes, large objects/scanout buffers that fail range overflow checks and thus
> are not mappable/fenceable keep getting evicted and reinserted leading to latencies. 
> I guess I could mark an object/vma as permanently un-mappable/un-fenceable and try
> not to map it subsequently but this would result in one scanout buffer that is mappable
> but others that are not. Would this be acceptable -- assuming we are pageflipping
> between multiple FBs?
> Any ideas on solving this issue cleanly?

We might just consider skipping PIN_MAPPABLE if the vma is too big.
What the specific defition of "too big" would be I'm not sure.
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_fb_pin.c b/drivers/gpu/drm/i915/display/intel_fb_pin.c
index 3f77f3013584..53c156d9a9f9 100644
--- a/drivers/gpu/drm/i915/display/intel_fb_pin.c
+++ b/drivers/gpu/drm/i915/display/intel_fb_pin.c
@@ -144,7 +144,7 @@  intel_pin_and_fence_fb_obj(struct drm_framebuffer *fb,
 
 	if (!ret) {
 		vma = i915_gem_object_pin_to_display_plane(obj, &ww, alignment,
-							   view, pinctl);
+							   view, pinctl, uses_fence);
 		if (IS_ERR(vma)) {
 			ret = PTR_ERR(vma);
 			goto err_unpin;
@@ -218,9 +218,16 @@  int intel_plane_pin_fb(struct intel_plane_state *plane_state)
 		INTEL_INFO(dev_priv)->display.cursor_needs_physical;
 
 	if (!intel_fb_uses_dpt(fb)) {
+		struct intel_crtc *crtc = to_intel_crtc(plane_state->hw.crtc);
+		struct intel_crtc_state *crtc_state =
+					to_intel_crtc_state(crtc->base.state);
+		bool uses_fence = intel_plane_uses_fence(plane_state);
+		bool is_bigjoiner = crtc_state->bigjoiner ||
+				    crtc_state->bigjoiner_slave;
+
 		vma = intel_pin_and_fence_fb_obj(fb, phys_cursor,
 						 &plane_state->view.gtt,
-						 intel_plane_uses_fence(plane_state),
+						 uses_fence && !is_bigjoiner,
 						 &plane_state->flags);
 		if (IS_ERR(vma))
 			return PTR_ERR(vma);
diff --git a/drivers/gpu/drm/i915/display/intel_overlay.c b/drivers/gpu/drm/i915/display/intel_overlay.c
index 7e3f5c6ca484..e9563b40b911 100644
--- a/drivers/gpu/drm/i915/display/intel_overlay.c
+++ b/drivers/gpu/drm/i915/display/intel_overlay.c
@@ -755,10 +755,14 @@  static u32 overlay_cmd_reg(struct drm_intel_overlay_put_image *params)
 	return cmd;
 }
 
-static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo)
+static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo,
+					     struct intel_overlay *overlay)
 {
 	struct i915_gem_ww_ctx ww;
 	struct i915_vma *vma;
+	const struct intel_plane_state *plane_state =
+		to_intel_plane_state(overlay->crtc->base.primary->state);
+	bool uses_fence = intel_plane_uses_fence(plane_state);
 	int ret;
 
 	i915_gem_ww_ctx_init(&ww, true);
@@ -766,7 +770,8 @@  static struct i915_vma *intel_overlay_pin_fb(struct drm_i915_gem_object *new_bo)
 	ret = i915_gem_object_lock(new_bo, &ww);
 	if (!ret) {
 		vma = i915_gem_object_pin_to_display_plane(new_bo, &ww, 0,
-							   NULL, PIN_MAPPABLE);
+							   NULL, PIN_MAPPABLE,
+							   uses_fence);
 		ret = PTR_ERR_OR_ZERO(vma);
 	}
 	if (ret == -EDEADLK) {
@@ -802,7 +807,7 @@  static int intel_overlay_do_put_image(struct intel_overlay *overlay,
 
 	atomic_inc(&dev_priv->gpu_error.pending_fb_pin);
 
-	vma = intel_overlay_pin_fb(new_bo);
+	vma = intel_overlay_pin_fb(new_bo, overlay);
 	if (IS_ERR(vma)) {
 		ret = PTR_ERR(vma);
 		goto out_pin_section;
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
index b684a62bf3b0..b9108f13cc49 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c
@@ -375,7 +375,8 @@  i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
 				     struct i915_gem_ww_ctx *ww,
 				     u32 alignment,
 				     const struct i915_ggtt_view *view,
-				     unsigned int flags)
+				     unsigned int flags,
+				     bool uses_fence)
 {
 	struct drm_i915_private *i915 = to_i915(obj->base.dev);
 	struct i915_vma *vma;
@@ -411,7 +412,8 @@  i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
 	 */
 	vma = ERR_PTR(-ENOSPC);
 	if ((flags & PIN_MAPPABLE) == 0 &&
-	    (!view || view->type == I915_GGTT_VIEW_NORMAL))
+	    (!view || view->type == I915_GGTT_VIEW_NORMAL) &&
+	    uses_fence)
 		vma = i915_gem_object_ggtt_pin_ww(obj, ww, view, 0, alignment,
 						  flags | PIN_MAPPABLE |
 						  PIN_NONBLOCK);
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
index a5479ac7a4ad..e83564fa57ca 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
+++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
@@ -534,7 +534,8 @@  i915_gem_object_pin_to_display_plane(struct drm_i915_gem_object *obj,
 				     struct i915_gem_ww_ctx *ww,
 				     u32 alignment,
 				     const struct i915_ggtt_view *view,
-				     unsigned int flags);
+				     unsigned int flags,
+				     bool uses_fence);
 
 void i915_gem_object_make_unshrinkable(struct drm_i915_gem_object *obj);
 void i915_gem_object_make_shrinkable(struct drm_i915_gem_object *obj);