[Mesa-dev] [PATCH 12/13] i965/fs: Use LD messages for pre-gen7 varying-index uniform loads
Eric Anholt
eric at anholt.net
Wed Mar 20 17:37:01 PDT 2013
This comes at a minor performance cost at the moment (-3.2% +/- 0.2%, n=14 on
my GM45 forced to load all uniforms through the varying-index path), but we
get a whole vec4 at a time to reuse in the next commit.
NOTE: This is a candidate for the 9.1 branch.
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 92 ++++++++++++++---------------
src/mesa/drivers/dri/i965/brw_fs.h | 3 +-
src/mesa/drivers/dri/i965/brw_fs_cse.cpp | 1 +
src/mesa/drivers/dri/i965/brw_fs_emit.cpp | 55 +++++++++++------
4 files changed, 84 insertions(+), 67 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 5d83e50..e504e3a 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -238,57 +238,53 @@ fs_visitor::VARYING_PULL_CONSTANT_LOAD(fs_reg dst, fs_reg surf_index,
exec_list instructions;
fs_inst *inst;
- if (intel->gen >= 7) {
- /* We have our constant surface use a pitch of 4 bytes, so our index can
- * be any component of a vector, and then we load 4 contiguous
- * components starting from that.
- *
- * We break down the const_offset to a portion added to the variable
- * offset and a portion done using reg_offset, which means that if you
- * have GLSL using something like "uniform vec4 a[20]; gl_FragColor =
- * a[i]", we'll temporarily generate 4 vec4 loads from offset i * 4, and
- * CSE can later notice that those loads are all the same and eliminate
- * the redundant ones.
- */
- fs_reg vec4_offset = fs_reg(this, glsl_type::int_type);
- instructions.push_tail(ADD(vec4_offset,
- varying_offset, const_offset & ~3));
-
- fs_reg vec4_result = fs_reg(GRF, virtual_grf_alloc(4), dst.type);
- inst = new(mem_ctx) fs_inst(FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_GEN7,
- vec4_result, surf_index, vec4_offset);
- inst->regs_written = 4;
- instructions.push_tail(inst);
-
- vec4_result.reg_offset += const_offset & 3;
- instructions.push_tail(MOV(dst, vec4_result));
- } else {
- fs_reg offset = fs_reg(this, glsl_type::uint_type);
- instructions.push_tail(ADD(offset, varying_offset, fs_reg(const_offset)));
-
- int base_mrf = 13;
- bool header_present = true;
-
- fs_reg mrf = fs_reg(MRF, base_mrf + header_present);
- mrf.type = BRW_REGISTER_TYPE_D;
-
- /* On gen6+ we want the dword offset passed in, but on gen4/5 we need a
- * dword-aligned byte offset.
+ /* We have our constant surface use a pitch of 4 bytes, so our index can
+ * be any component of a vector, and then we load 4 contiguous
+ * components starting from that.
+ *
+ * We break down the const_offset to a portion added to the variable
+ * offset and a portion done using reg_offset, which means that if you
+ * have GLSL using something like "uniform vec4 a[20]; gl_FragColor =
+ * a[i]", we'll temporarily generate 4 vec4 loads from offset i * 4, and
+ * CSE can later notice that those loads are all the same and eliminate
+ * the redundant ones.
+ */
+ fs_reg vec4_offset = fs_reg(this, glsl_type::int_type);
+ instructions.push_tail(ADD(vec4_offset,
+ varying_offset, const_offset & ~3));
+
+ int scale = 1;
+ if (intel->gen == 4 && dispatch_width == 8) {
+ /* Pre-gen5, we can either use a SIMD8 message that requires (header,
+ * u, v, r) as parameters, or we can just use the SIMD16 message
+ * consisting of (header, u). We choose the second, at the cost of a
+ * longer return length.
*/
- if (intel->gen == 6) {
- instructions.push_tail(MOV(mrf, offset));
- } else {
- instructions.push_tail(MUL(mrf, offset, fs_reg(4)));
- }
- inst = new(mem_ctx) fs_inst(FS_OPCODE_VARYING_PULL_CONSTANT_LOAD,
- dst, surf_index);
- inst->header_present = header_present;
- inst->base_mrf = base_mrf;
- inst->mlen = header_present + dispatch_width / 8;
+ scale = 2;
+ }
- instructions.push_tail(inst);
+ enum opcode op;
+ if (intel->gen >= 7)
+ op = FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_GEN7;
+ else
+ op = FS_OPCODE_VARYING_PULL_CONSTANT_LOAD;
+ fs_reg vec4_result = fs_reg(GRF, virtual_grf_alloc(4 * scale), dst.type);
+ inst = new(mem_ctx) fs_inst(op, vec4_result, surf_index, vec4_offset);
+ inst->regs_written = 4 * scale;
+ instructions.push_tail(inst);
+
+ if (intel->gen < 7) {
+ inst->base_mrf = 13;
+ inst->header_present = true;
+ if (intel->gen == 4)
+ inst->mlen = 3;
+ else
+ inst->mlen = 1 + dispatch_width / 8;
}
+ vec4_result.reg_offset += (const_offset & 3) * scale;
+ instructions.push_tail(MOV(dst, vec4_result));
+
return instructions;
}
@@ -766,7 +762,7 @@ fs_visitor::implied_mrf_writes(fs_inst *inst)
case FS_OPCODE_UNSPILL:
return 1;
case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD:
- return inst->header_present;
+ return inst->mlen;
case FS_OPCODE_SPILL:
return 2;
default:
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 0c5aad1..b19dcf5 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -541,7 +541,8 @@ private:
struct brw_reg surf_index,
struct brw_reg offset);
void generate_varying_pull_constant_load(fs_inst *inst, struct brw_reg dst,
- struct brw_reg index);
+ struct brw_reg index,
+ struct brw_reg offset);
void generate_varying_pull_constant_load_gen7(fs_inst *inst,
struct brw_reg dst,
struct brw_reg index,
diff --git a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
index 01a64d2..6984e1a 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_cse.cpp
@@ -69,6 +69,7 @@ is_expression(const fs_inst *const inst)
case BRW_OPCODE_LRP:
case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD:
case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_GEN7:
+ case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD:
case FS_OPCODE_CINTERP:
case FS_OPCODE_LINTERP:
return true;
diff --git a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
index 4b3c43f..6fec526 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_emit.cpp
@@ -677,47 +677,66 @@ fs_generator::generate_uniform_pull_constant_load_gen7(fs_inst *inst,
void
fs_generator::generate_varying_pull_constant_load(fs_inst *inst,
struct brw_reg dst,
- struct brw_reg index)
+ struct brw_reg index,
+ struct brw_reg offset)
{
assert(intel->gen < 7); /* Should use the gen7 variant. */
assert(inst->header_present);
+ assert(inst->mlen);
assert(index.file == BRW_IMMEDIATE_VALUE &&
index.type == BRW_REGISTER_TYPE_UD);
uint32_t surf_index = index.dw1.ud;
- uint32_t msg_type, msg_control, rlen;
- if (intel->gen >= 6)
- msg_type = GEN6_DATAPORT_READ_MESSAGE_DWORD_SCATTERED_READ;
- else if (intel->gen == 5 || intel->is_g4x)
- msg_type = G45_DATAPORT_READ_MESSAGE_DWORD_SCATTERED_READ;
- else
- msg_type = BRW_DATAPORT_READ_MESSAGE_DWORD_SCATTERED_READ;
-
+ uint32_t simd_mode, rlen, msg_type;
if (dispatch_width == 16) {
- msg_control = BRW_DATAPORT_DWORD_SCATTERED_BLOCK_16DWORDS;
- rlen = 2;
+ simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
+ rlen = 8;
} else {
- msg_control = BRW_DATAPORT_DWORD_SCATTERED_BLOCK_8DWORDS;
- rlen = 1;
+ simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD8;
+ rlen = 4;
+ }
+
+ if (intel->gen >= 5)
+ msg_type = GEN5_SAMPLER_MESSAGE_SAMPLE_LD;
+ else {
+ /* We always use the SIMD16 message so that we only have to load U, and
+ * not V/R/LOD.
+ */
+ msg_type = BRW_SAMPLER_MESSAGE_SIMD16_LD;
+ assert(inst->mlen == 3);
+ assert(inst->regs_written == 8);
+ rlen = 8;
+ simd_mode = BRW_SAMPLER_SIMD_MODE_SIMD16;
}
+ struct brw_reg offset_mrf = retype(brw_message_reg(inst->base_mrf + 1),
+ BRW_REGISTER_TYPE_D);
+ brw_MOV(p, offset_mrf, offset);
+
struct brw_reg header = brw_vec8_grf(0, 0);
gen6_resolve_implied_move(p, &header, inst->base_mrf);
struct brw_instruction *send = brw_next_insn(p, BRW_OPCODE_SEND);
+ send->header.compression_control = BRW_COMPRESSION_NONE;
brw_set_dest(p, send, dst);
brw_set_src0(p, send, header);
if (intel->gen < 6)
send->header.destreg__conditionalmod = inst->base_mrf;
- brw_set_dp_read_message(p, send,
+
+ /* Our surface is set up as floats, regardless of what actual data is
+ * stored in it.
+ */
+ uint32_t return_format = BRW_SAMPLER_RETURN_FORMAT_FLOAT32;
+ brw_set_sampler_message(p, send,
surf_index,
- msg_control,
+ 0, /* sampler (unused) */
msg_type,
- BRW_DATAPORT_READ_TARGET_DATA_CACHE,
+ rlen,
inst->mlen,
inst->header_present,
- rlen);
+ simd_mode,
+ return_format);
}
void
@@ -1272,7 +1291,7 @@ fs_generator::generate_code(exec_list *instructions)
break;
case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD:
- generate_varying_pull_constant_load(inst, dst, src[0]);
+ generate_varying_pull_constant_load(inst, dst, src[0], src[1]);
break;
case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD_GEN7:
--
1.7.10.4
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