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anv: add dynamic buffer offsets support with independent sets

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With independent sets, we're not able to compute immediate values for
the index at which to read anv_push_constants::dynamic_offsets to get
the offset of a dynamic buffer. This is because the pipeline layout
may not have all the descriptor set layouts when we compile the
shader.

To solve that issue, we insert a layer of indirection.

This reworks the dynamic buffer offset storage with a 2D array in
anv_cmd_pipeline_state :

   dynamic_offsets[MAX_SETS][MAX_DYN_BUFFERS]

When the pipeline or the dynamic buffer offsets are updated, we
flatten that array into the
anv_push_constants::dynamic_offsets[MAX_DYN_BUFFERS] array.

For shaders compiled with independent sets, the bottom 6 bits of
element X in anv_push_constants::desc_sets[] is used to specify the
base offsets into the anv_push_constants::dynamic_offsets[] for the
set X.

The computation in the shader is now something like :

  base_dyn_buffer_set_idx = anv_push_constants::desc_sets[set_idx] & 0x3f
  dyn_buffer_offset = anv_push_constants::dynamic_offsets[base_dyn_buffer_set_idx + dynamic_buffer_idx]

It was suggested by Faith to use a different push constant buffer with
dynamic_offsets prepared for each stage when using independent sets
instead, but it feels easier to understand this way. And there is some
room for optimization if you are set X and that you know all the sets in
the range [0, X], then you can still avoid the indirection. Separate
push constant allocations per stage do have a CPU cost.

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15637>
This commit is contained in:
Lionel Landwerlin
2022-04-06 18:12:02 +03:00
committed by Marge Bot
parent 16c7c37718
commit 0b8a2de2a1
11 changed files with 384 additions and 100 deletions
Download Patch File Download Diff File Expand all files Collapse all files
src/intel/vulkan/anv_nir_compute_push_layout.c
+17
View File
@@ -68,6 +68,7 @@ anv_nir_compute_push_layout(nir_shader *nir,
}
case nir_intrinsic_load_desc_set_address_intel:
case nir_intrinsic_load_desc_set_dynamic_index_intel:
push_start = MIN2(push_start,
offsetof(struct anv_push_constants, desc_sets));
push_end = MAX2(push_end, push_start +
@@ -171,6 +172,22 @@ anv_nir_compute_push_layout(nir_shader *nir,
.base = offsetof(struct anv_push_constants, desc_sets),
.range = sizeof_field(struct anv_push_constants, desc_sets),
.dest_type = nir_type_uint64);
pc_load = nir_iand_imm(b, pc_load, ANV_DESCRIPTOR_SET_ADDRESS_MASK);
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, pc_load);
break;
}
case nir_intrinsic_load_desc_set_dynamic_index_intel: {
b->cursor = nir_before_instr(&intrin->instr);
nir_ssa_def *pc_load = nir_load_uniform(b, 1, 64,
nir_imul_imm(b, intrin->src[0].ssa, sizeof(uint64_t)),
.base = offsetof(struct anv_push_constants, desc_sets),
.range = sizeof_field(struct anv_push_constants, desc_sets),
.dest_type = nir_type_uint64);
pc_load = nir_i2i32(
b,
nir_iand_imm(
b, pc_load, ANV_DESCRIPTOR_SET_DYNAMIC_INDEX_MASK));
nir_ssa_def_rewrite_uses(&intrin->dest.ssa, pc_load);
break;
}