[Mesa-dev] [PATCH 4/4] radv: reduce the number of loaded channels for vertex input fetches
Bas Nieuwenhuizen
bas at basnieuwenhuizen.nl
Wed Feb 13 21:59:50 UTC 2019
On Tue, Feb 12, 2019 at 3:07 PM Samuel Pitoiset
<samuel.pitoiset at gmail.com> wrote:
>
> It's unnecessary to load more channels than the vertex attribute
> format. The remaining channels are filled with 0 for y and z,
> and 1 for w.
>
> 29077 shaders in 15096 tests
> Totals:
> SGPRS: 1321605 -> 1318869 (-0.21 %)
> VGPRS: 935236 -> 932252 (-0.32 %)
> Spilled SGPRs: 24860 -> 24776 (-0.34 %)
> Code Size: 49832348 -> 49819464 (-0.03 %) bytes
> Max Waves: 242101 -> 242611 (0.21 %)
>
> Totals from affected shaders:
> SGPRS: 93675 -> 90939 (-2.92 %)
> VGPRS: 58016 -> 55032 (-5.14 %)
> Spilled SGPRs: 172 -> 88 (-48.84 %)
> Code Size: 2862740 -> 2849856 (-0.45 %) bytes
> Max Waves: 15474 -> 15984 (3.30 %)
>
> This mostly helps Croteam games (Talos/Sam2017).
>
> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
> ---
> src/amd/vulkan/radv_nir_to_llvm.c | 83 ++++++++++++++++++++++++++++++-
> 1 file changed, 81 insertions(+), 2 deletions(-)
>
> diff --git a/src/amd/vulkan/radv_nir_to_llvm.c b/src/amd/vulkan/radv_nir_to_llvm.c
> index 7f74678d5f1..b1e0c64e4e1 100644
> --- a/src/amd/vulkan/radv_nir_to_llvm.c
> +++ b/src/amd/vulkan/radv_nir_to_llvm.c
> @@ -1967,6 +1967,72 @@ adjust_vertex_fetch_alpha(struct radv_shader_context *ctx,
> return alpha;
> }
>
> +static unsigned
> +get_num_channels_from_data_format(unsigned data_format)
> +{
> + switch (data_format) {
> + case V_008F0C_BUF_DATA_FORMAT_8:
> + case V_008F0C_BUF_DATA_FORMAT_16:
> + case V_008F0C_BUF_DATA_FORMAT_32:
> + return 1;
> + case V_008F0C_BUF_DATA_FORMAT_8_8:
> + case V_008F0C_BUF_DATA_FORMAT_16_16:
> + case V_008F0C_BUF_DATA_FORMAT_32_32:
> + return 2;
> + case V_008F0C_BUF_DATA_FORMAT_10_11_11:
> + case V_008F0C_BUF_DATA_FORMAT_11_11_10:
> + case V_008F0C_BUF_DATA_FORMAT_32_32_32:
> + return 3;
> + case V_008F0C_BUF_DATA_FORMAT_8_8_8_8:
> + case V_008F0C_BUF_DATA_FORMAT_10_10_10_2:
> + case V_008F0C_BUF_DATA_FORMAT_2_10_10_10:
> + case V_008F0C_BUF_DATA_FORMAT_16_16_16_16:
> + case V_008F0C_BUF_DATA_FORMAT_32_32_32_32:
> + return 4;
> + default:
> + break;
> + }
> +
> + return 4;
> +}
> +
> +static LLVMValueRef
> +radv_fixup_vertex_input_fetches(struct radv_shader_context *ctx,
> + LLVMValueRef value,
> + unsigned num_channels,
> + bool is_float)
> +{
> + LLVMValueRef zero = is_float ? ctx->ac.f32_0 : ctx->ac.i32_0;
> + LLVMValueRef one = is_float ? ctx->ac.f32_1 : ctx->ac.i32_1;
> + LLVMTypeRef elemtype;
> + LLVMValueRef chan[4];
> +
> + if (LLVMGetTypeKind(LLVMTypeOf(value)) == LLVMVectorTypeKind) {
> + unsigned vec_size = LLVMGetVectorSize(LLVMTypeOf(value));
> +
> + if (num_channels == 4 && vec_size == 4)
> + return value;
Just num_channels == vec_size ?
> +
> + num_channels = MIN2(num_channels, vec_size);
> +
> + for (unsigned i = 0; i < num_channels; i++)
> + chan[i] = ac_llvm_extract_elem(&ctx->ac, value, i);
> +
> + elemtype = LLVMGetElementType(LLVMTypeOf(value));
> + } else {
> + if (num_channels) {
> + assert(num_channels == 1);
> + chan[0] = value;
> + }
> + elemtype = LLVMTypeOf(value);
> + }
> +
> + for (unsigned i = num_channels; i < 4; i++)
> + chan[i] = i == 3 ? one : zero;
> +
> + return ac_build_gather_values(&ctx->ac, chan, 4);
> +}
> +
> static void
> handle_vs_input_decl(struct radv_shader_context *ctx,
> struct nir_variable *variable)
> @@ -1979,7 +2045,7 @@ handle_vs_input_decl(struct radv_shader_context *ctx,
> unsigned attrib_count = glsl_count_attribute_slots(variable->type, true);
> uint8_t input_usage_mask =
> ctx->shader_info->info.vs.input_usage_mask[variable->data.location];
> - unsigned num_channels = util_last_bit(input_usage_mask);
> + unsigned num_input_channels = util_last_bit(input_usage_mask);
>
> variable->data.driver_location = variable->data.location * 4;
>
> @@ -1987,6 +2053,10 @@ handle_vs_input_decl(struct radv_shader_context *ctx,
> for (unsigned i = 0; i < attrib_count; ++i) {
> LLVMValueRef output[4];
> unsigned attrib_index = variable->data.location + i - VERT_ATTRIB_GENERIC0;
> + unsigned attrib_format = ctx->options->key.vs.vertex_attribute_formats[attrib_index];
> + unsigned data_format = attrib_format & 0x0f;
> + unsigned num_format = (attrib_format >> 4) & 0x07;
> + bool is_float = num_format == V_008F0C_BUF_NUM_FORMAT_FLOAT;
>
> if (ctx->options->key.vs.instance_rate_inputs & (1u << attrib_index)) {
> uint32_t divisor = ctx->options->key.vs.instance_rate_divisors[attrib_index];
> @@ -2018,12 +2088,21 @@ handle_vs_input_decl(struct radv_shader_context *ctx,
>
> t_list = ac_build_load_to_sgpr(&ctx->ac, t_list_ptr, t_offset);
>
> + /* Adjust the number of channels to load based on the vertex
> + * attribute format.
> + */
> + unsigned num_format_channels = get_num_channels_from_data_format(data_format);
> + unsigned num_channels = MIN2(num_input_channels, num_format_channels);
> +
> + assert(num_channels <= num_input_channels);
Seems kinda redundant given the MIN2 above.
Does this work with 3 components?
Otherwise r-b for the series.
> +
> input = ac_build_buffer_load_format(&ctx->ac, t_list,
> buffer_index,
> ctx->ac.i32_0,
> num_channels, false, true);
>
> - input = ac_build_expand_to_vec4(&ctx->ac, input, num_channels);
> + input = radv_fixup_vertex_input_fetches(ctx, input, num_channels,
> + is_float);
>
> for (unsigned chan = 0; chan < 4; chan++) {
> LLVMValueRef llvm_chan = LLVMConstInt(ctx->ac.i32, chan, false);
> --
> 2.20.1
>
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