v2: Update comments, function signatures, and add assertions. Signed-off-by: Nanley Chery <nanley.g.ch...@intel.com> --- src/intel/vulkan/anv_image.c | 78 ++++++++++++++++++++++++++++++++++++++++++ src/intel/vulkan/anv_private.h | 12 +++++++ 2 files changed, 90 insertions(+)
diff --git a/src/intel/vulkan/anv_image.c b/src/intel/vulkan/anv_image.c index f33a445d1d..70a8c28bac 100644 --- a/src/intel/vulkan/anv_image.c +++ b/src/intel/vulkan/anv_image.c @@ -117,6 +117,82 @@ add_surface(struct anv_image *image, struct anv_surface *surf) } /** + * For color images that have an auxiliary surface, request allocation for an + * additional buffer that mainly stores fast-clear values. Use of this buffer + * allows us to access the image's subresources while being aware of their + * fast-clear values in non-trivial cases (e.g., outside of a render pass in + * which a fast clear has occurred). + * + * For the purpose of discoverability, the algorithm used to manage this buffer + * is described here. A clear value in this buffer is updated when a fast clear + * is performed on a subresource. One of two synchronization operations is + * performed in order for a following memory access to use the fast-clear + * value: + * a. Copy the value from the buffer to the surface state object used for + * reading. This is done implicitly when the value is the clear value + * predetermined to be the default in other surface state objects. This + * is currently only done explicitly for the operation below. + * b. Do (a) and use the surface state object to resolve the subresource. + * This is only done during layout transitions for decent performance. + * + * With the above scheme, we can fast-clear whenever the hardware allows except + * for two cases in which synchronization becomes impossible or undesirable: + * * The subresource is in the GENERAL layout and is cleared to a value + * other than the special default value. + * + * Performing a synchronization operation in order to read from the + * subresource is undesirable in this case. Firstly, b) is not an option + * because a layout transition isn't required between a write and read of + * an image in the GENERAL layout. Secondly, it's undesirable to do a) + * explicitly because it would require large infrastructural changes. The + * Vulkan API supports us in deciding not to optimize this layout by + * stating that using this layout may cause suboptimal performance. NOTE: + * the auxiliary buffer must always be enabled to support a) implicitly. + * + * + * * For the given miplevel, only some of the layers are cleared at once. + * + * If the user clears each layer to a different value, then tries to + * render to multiple layers at once, we have no ability to perform a + * synchronization operation in between. a) is not helpful because the + * object can only hold one clear value. b) is not an option because a + * layout transition isn't required in this case. + */ +static void +add_fast_clear_state_buffer(struct anv_image *image, + const struct anv_device *device) +{ + assert(image && device); + assert(image->aux_surface.isl.size > 0 && + image->aspects == VK_IMAGE_ASPECT_COLOR_BIT); + + /* The offset to the buffer of clear values must be dword-aligned for GPU + * memcpy operations. It is located immediately after the auxiliary surface. + */ + + /* Tiled images are guaranteed to be 4K aligned, so the image alignment + * should also be dword-aligned. + */ + assert(image->alignment % 4 == 0); + + /* Auxiliary buffers should be a multiple of 4K, so the start of the clear + * values buffer should already be dword-aligned. + */ + assert(image->aux_surface.isl.size % 4 == 0); + + /* This buffer should be at the very end of the image. */ + assert(image->size == + image->aux_surface.offset + image->aux_surface.isl.size); + + const unsigned entry_size = anv_fast_clear_state_entry_size(device); + /* There's no padding between entries, so ensure that they're always a + * multiple of 32 bits in order to enable GPU memcpy operations. + */ + assert(entry_size % 4 == 0); + image->size += entry_size * anv_image_aux_levels(image); +} + +/** * Initialize the anv_image::*_surface selected by \a aspect. Then update the * image's memory requirements (that is, the image's size and alignment). * @@ -230,6 +306,7 @@ make_surface(const struct anv_device *dev, } add_surface(image, &image->aux_surface); + add_fast_clear_state_buffer(image, dev); /* For images created without MUTABLE_FORMAT_BIT set, we know that * they will always be used with the original format. In @@ -253,6 +330,7 @@ make_surface(const struct anv_device *dev, &image->aux_surface.isl); if (ok) { add_surface(image, &image->aux_surface); + add_fast_clear_state_buffer(image, dev); image->aux_usage = ISL_AUX_USAGE_MCS; } } diff --git a/src/intel/vulkan/anv_private.h b/src/intel/vulkan/anv_private.h index 9a5d2d6fa4..3635bc8a1a 100644 --- a/src/intel/vulkan/anv_private.h +++ b/src/intel/vulkan/anv_private.h @@ -2084,6 +2084,18 @@ anv_image_aux_layers(const struct anv_image * const image, } } +static inline unsigned +anv_fast_clear_state_entry_size(const struct anv_device *device) +{ + assert(device); + /* Entry contents: + * +----------------------+ + * | clear value dword(s) | + * +----------------------+ + */ + return device->isl_dev.ss.clear_value_size; +} + /* Returns true if a HiZ-enabled depth buffer can be sampled from. */ static inline bool anv_can_sample_with_hiz(const struct gen_device_info * const devinfo, -- 2.13.3 _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev