From 0cb7d7b4b7c32246d4c4225a1d17d7ff79a7526d Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Kristian=20H=C3=B8gsberg=20Kristensen?= Date: Wed, 21 Oct 2015 23:43:34 -0700 Subject: [PATCH] i965/fs: Optimize ssbo stores MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Reviewed-by: Francisco Jerez Write groups of enabled components together. Signed-off-by: Kristian Høgsberg Kristensen --- src/mesa/drivers/dri/i965/brw_fs_nir.cpp | 55 +++++++++++------------- 1 file changed, 25 insertions(+), 30 deletions(-) diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp index a82c616e8fb..4950ba4fe67 100644 --- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp +++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp @@ -1759,45 +1759,40 @@ fs_visitor::nir_emit_intrinsic(const fs_builder &bld, nir_intrinsic_instr *instr nir->info.num_ssbos - 1); } - /* Offset */ - fs_reg offset_reg = vgrf(glsl_type::uint_type); - unsigned const_offset_bytes = 0; - if (has_indirect) { - bld.MOV(offset_reg, get_nir_src(instr->src[2])); - } else { - const_offset_bytes = instr->const_index[0]; - bld.MOV(offset_reg, fs_reg(const_offset_bytes)); - } - /* Value */ fs_reg val_reg = get_nir_src(instr->src[0]); /* Writemask */ unsigned writemask = instr->const_index[1]; - /* Write each component present in the writemask */ - unsigned skipped_channels = 0; - for (int i = 0; i < instr->num_components; i++) { - int component_mask = 1 << i; - if (writemask & component_mask) { - if (skipped_channels) { - if (!has_indirect) { - const_offset_bytes += 4 * skipped_channels; - bld.MOV(offset_reg, fs_reg(const_offset_bytes)); - } else { - bld.ADD(offset_reg, offset_reg, - brw_imm_ud(4 * skipped_channels)); - } - skipped_channels = 0; - } + /* Combine groups of consecutive enabled channels in one write + * message. We use ffs to find the first enabled channel and then ffs on + * the bit-inverse, down-shifted writemask to determine the length of + * the block of enabled bits. + */ + while (writemask) { + unsigned first_component = ffs(writemask) - 1; + unsigned length = ffs(~(writemask >> first_component)) - 1; + fs_reg offset_reg; - emit_untyped_write(bld, surf_index, offset_reg, - offset(val_reg, bld, i), - 1 /* dims */, 1 /* size */, - BRW_PREDICATE_NONE); + if (!has_indirect) { + offset_reg = fs_reg(instr->const_index[0] + 4 * first_component); + } else { + offset_reg = vgrf(glsl_type::uint_type); + bld.ADD(offset_reg, + retype(get_nir_src(instr->src[2]), BRW_REGISTER_TYPE_UD), + fs_reg(4 * first_component)); } - skipped_channels++; + emit_untyped_write(bld, surf_index, offset_reg, + offset(val_reg, bld, first_component), + 1 /* dims */, length, + BRW_PREDICATE_NONE); + + /* Clear the bits in the writemask that we just wrote, then try + * again to see if more channels are left. + */ + writemask &= (15 << (first_component + length)); } break; }