brw_fs_fp.cpp \
brw_fs_live_variables.cpp \
brw_fs_reg_allocate.cpp \
- brw_fs_schedule_instructions.cpp \
brw_fs_vector_splitting.cpp \
brw_fs_visitor.cpp \
brw_gs.c \
brw_program.c \
brw_primitive_restart.c \
brw_queryobj.c \
+ brw_schedule_instructions.cpp \
brw_sf.c \
brw_sf_emit.c \
brw_sf_state.c \
+++ /dev/null
-/*
- * Copyright © 2010 Intel Corporation
- *
- * Permission is hereby granted, free of charge, to any person obtaining a
- * copy of this software and associated documentation files (the "Software"),
- * to deal in the Software without restriction, including without limitation
- * the rights to use, copy, modify, merge, publish, distribute, sublicense,
- * and/or sell copies of the Software, and to permit persons to whom the
- * Software is furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice (including the next
- * paragraph) shall be included in all copies or substantial portions of the
- * Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
- * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
- * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
- * IN THE SOFTWARE.
- *
- * Authors:
- * Eric Anholt <eric@anholt.net>
- *
- */
-
-#include "brw_fs.h"
-#include "glsl/glsl_types.h"
-#include "glsl/ir_optimization.h"
-#include "glsl/ir_print_visitor.h"
-
-/** @file brw_fs_schedule_instructions.cpp
- *
- * List scheduling of FS instructions.
- *
- * The basic model of the list scheduler is to take a basic block,
- * compute a DAG of the dependencies (RAW ordering with latency, WAW
- * ordering with latency, WAR ordering), and make a list of the DAG heads.
- * Heuristically pick a DAG head, then put all the children that are
- * now DAG heads into the list of things to schedule.
- *
- * The heuristic is the important part. We're trying to be cheap,
- * since actually computing the optimal scheduling is NP complete.
- * What we do is track a "current clock". When we schedule a node, we
- * update the earliest-unblocked clock time of its children, and
- * increment the clock. Then, when trying to schedule, we just pick
- * the earliest-unblocked instruction to schedule.
- *
- * Note that often there will be many things which could execute
- * immediately, and there are a range of heuristic options to choose
- * from in picking among those.
- */
-
-static bool debug = false;
-
-class schedule_node : public exec_node
-{
-public:
- schedule_node(fs_inst *inst, const struct intel_context *intel)
- {
- this->inst = inst;
- this->child_array_size = 0;
- this->children = NULL;
- this->child_latency = NULL;
- this->child_count = 0;
- this->parent_count = 0;
- this->unblocked_time = 0;
-
- /* We can't measure Gen6 timings directly but expect them to be much
- * closer to Gen7 than Gen4.
- */
- if (intel->gen >= 6)
- set_latency_gen7(intel->is_haswell);
- else
- set_latency_gen4();
- }
-
- void set_latency_gen4();
- void set_latency_gen7(bool is_haswell);
-
- fs_inst *inst;
- schedule_node **children;
- int *child_latency;
- int child_count;
- int parent_count;
- int child_array_size;
- int unblocked_time;
- int latency;
-};
-
-void
-schedule_node::set_latency_gen4()
-{
- int chans = 8;
- int math_latency = 22;
-
- switch (inst->opcode) {
- case SHADER_OPCODE_RCP:
- this->latency = 1 * chans * math_latency;
- break;
- case SHADER_OPCODE_RSQ:
- this->latency = 2 * chans * math_latency;
- break;
- case SHADER_OPCODE_INT_QUOTIENT:
- case SHADER_OPCODE_SQRT:
- case SHADER_OPCODE_LOG2:
- /* full precision log. partial is 2. */
- this->latency = 3 * chans * math_latency;
- break;
- case SHADER_OPCODE_INT_REMAINDER:
- case SHADER_OPCODE_EXP2:
- /* full precision. partial is 3, same throughput. */
- this->latency = 4 * chans * math_latency;
- break;
- case SHADER_OPCODE_POW:
- this->latency = 8 * chans * math_latency;
- break;
- case SHADER_OPCODE_SIN:
- case SHADER_OPCODE_COS:
- /* minimum latency, max is 12 rounds. */
- this->latency = 5 * chans * math_latency;
- break;
- default:
- this->latency = 2;
- break;
- }
-}
-
-void
-schedule_node::set_latency_gen7(bool is_haswell)
-{
- switch (inst->opcode) {
- case BRW_OPCODE_MAD:
- /* 2 cycles
- * (since the last two src operands are in different register banks):
- * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
- *
- * 3 cycles on IVB, 4 on HSW
- * (since the last two src operands are in the same register bank):
- * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
- *
- * 18 cycles on IVB, 16 on HSW
- * (since the last two src operands are in different register banks):
- * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
- * mov(8) null g4<4,5,1>F { align16 WE_normal 1Q };
- *
- * 20 cycles on IVB, 18 on HSW
- * (since the last two src operands are in the same register bank):
- * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
- * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
- */
-
- /* Our register allocator doesn't know about register banks, so use the
- * higher latency.
- */
- latency = is_haswell ? 16 : 18;
- break;
-
- case BRW_OPCODE_LRP:
- /* 2 cycles
- * (since the last two src operands are in different register banks):
- * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
- *
- * 3 cycles on IVB, 4 on HSW
- * (since the last two src operands are in the same register bank):
- * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
- *
- * 16 cycles on IVB, 14 on HSW
- * (since the last two src operands are in different register banks):
- * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
- * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
- *
- * 16 cycles
- * (since the last two src operands are in the same register bank):
- * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
- * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
- */
-
- /* Our register allocator doesn't know about register banks, so use the
- * higher latency.
- */
- latency = 14;
- break;
-
- case SHADER_OPCODE_RCP:
- case SHADER_OPCODE_RSQ:
- case SHADER_OPCODE_SQRT:
- case SHADER_OPCODE_LOG2:
- case SHADER_OPCODE_EXP2:
- case SHADER_OPCODE_SIN:
- case SHADER_OPCODE_COS:
- /* 2 cycles:
- * math inv(8) g4<1>F g2<0,1,0>F null { align1 WE_normal 1Q };
- *
- * 18 cycles:
- * math inv(8) g4<1>F g2<0,1,0>F null { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * Same for exp2, log2, rsq, sqrt, sin, cos.
- */
- latency = is_haswell ? 14 : 16;
- break;
-
- case SHADER_OPCODE_POW:
- /* 2 cycles:
- * math pow(8) g4<1>F g2<0,1,0>F g2.1<0,1,0>F { align1 WE_normal 1Q };
- *
- * 26 cycles:
- * math pow(8) g4<1>F g2<0,1,0>F g2.1<0,1,0>F { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- */
- latency = is_haswell ? 22 : 24;
- break;
-
- case SHADER_OPCODE_TEX:
- case SHADER_OPCODE_TXD:
- case SHADER_OPCODE_TXF:
- case SHADER_OPCODE_TXL:
- /* 18 cycles:
- * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
- * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
- * send(8) g4<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- *
- * 697 +/-49 cycles (min 610, n=26):
- * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
- * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
- * send(8) g4<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * So the latency on our first texture load of the batchbuffer takes
- * ~700 cycles, since the caches are cold at that point.
- *
- * 840 +/- 92 cycles (min 720, n=25):
- * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
- * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
- * send(8) g4<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- * send(8) g4<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * On the second load, it takes just an extra ~140 cycles, and after
- * accounting for the 14 cycles of the MOV's latency, that makes ~130.
- *
- * 683 +/- 49 cycles (min = 602, n=47):
- * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
- * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
- * send(8) g4<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- * send(8) g50<1>UW g114<8,8,1>F
- * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * The unit appears to be pipelined, since this matches up with the
- * cache-cold case, despite there being two loads here. If you replace
- * the g4 in the MOV to null with g50, it's still 693 +/- 52 (n=39).
- *
- * So, take some number between the cache-hot 140 cycles and the
- * cache-cold 700 cycles. No particular tuning was done on this.
- *
- * I haven't done significant testing of the non-TEX opcodes. TXL at
- * least looked about the same as TEX.
- */
- latency = 200;
- break;
-
- case SHADER_OPCODE_TXS:
- /* Testing textureSize(sampler2D, 0), one load was 420 +/- 41
- * cycles (n=15):
- * mov(8) g114<1>UD 0D { align1 WE_normal 1Q };
- * send(8) g6<1>UW g114<8,8,1>F
- * sampler (10, 0, 10, 1) mlen 1 rlen 4 { align1 WE_normal 1Q };
- * mov(16) g6<1>F g6<8,8,1>D { align1 WE_normal 1Q };
- *
- *
- * Two loads was 535 +/- 30 cycles (n=19):
- * mov(16) g114<1>UD 0D { align1 WE_normal 1H };
- * send(16) g6<1>UW g114<8,8,1>F
- * sampler (10, 0, 10, 2) mlen 2 rlen 8 { align1 WE_normal 1H };
- * mov(16) g114<1>UD 0D { align1 WE_normal 1H };
- * mov(16) g6<1>F g6<8,8,1>D { align1 WE_normal 1H };
- * send(16) g8<1>UW g114<8,8,1>F
- * sampler (10, 0, 10, 2) mlen 2 rlen 8 { align1 WE_normal 1H };
- * mov(16) g8<1>F g8<8,8,1>D { align1 WE_normal 1H };
- * add(16) g6<1>F g6<8,8,1>F g8<8,8,1>F { align1 WE_normal 1H };
- *
- * Since the only caches that should matter are just the
- * instruction/state cache containing the surface state, assume that we
- * always have hot caches.
- */
- latency = 100;
- break;
-
- case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD:
- case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD:
- /* testing using varying-index pull constants:
- *
- * 16 cycles:
- * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
- * send(8) g4<1>F g4<8,8,1>D
- * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
- *
- * ~480 cycles:
- * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
- * send(8) g4<1>F g4<8,8,1>D
- * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * ~620 cycles:
- * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
- * send(8) g4<1>F g4<8,8,1>D
- * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- * send(8) g4<1>F g4<8,8,1>D
- * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- *
- * So, if it's cache-hot, it's about 140. If it's cache cold, it's
- * about 460. We expect to mostly be cache hot, so pick something more
- * in that direction.
- */
- latency = 200;
- break;
-
- default:
- /* 2 cycles:
- * mul(8) g4<1>F g2<0,1,0>F 0.5F { align1 WE_normal 1Q };
- *
- * 16 cycles:
- * mul(8) g4<1>F g2<0,1,0>F 0.5F { align1 WE_normal 1Q };
- * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
- */
- latency = 14;
- break;
- }
-}
-
-class instruction_scheduler {
-public:
- instruction_scheduler(fs_visitor *v, void *mem_ctx, int grf_count,
- bool post_reg_alloc)
- {
- this->v = v;
- this->mem_ctx = ralloc_context(mem_ctx);
- this->grf_count = grf_count;
- this->instructions.make_empty();
- this->instructions_to_schedule = 0;
- this->post_reg_alloc = post_reg_alloc;
- }
-
- ~instruction_scheduler()
- {
- ralloc_free(this->mem_ctx);
- }
- void add_barrier_deps(schedule_node *n);
- void add_dep(schedule_node *before, schedule_node *after, int latency);
- void add_dep(schedule_node *before, schedule_node *after);
-
- void add_inst(fs_inst *inst);
- void calculate_deps();
- void schedule_instructions(fs_inst *next_block_header);
-
- bool is_compressed(fs_inst *inst);
-
- void *mem_ctx;
-
- bool post_reg_alloc;
- int instructions_to_schedule;
- int grf_count;
- exec_list instructions;
- fs_visitor *v;
-};
-
-void
-instruction_scheduler::add_inst(fs_inst *inst)
-{
- schedule_node *n = new(mem_ctx) schedule_node(inst, v->intel);
-
- assert(!inst->is_head_sentinel());
- assert(!inst->is_tail_sentinel());
-
- this->instructions_to_schedule++;
-
- inst->remove();
- instructions.push_tail(n);
-}
-
-/**
- * Add a dependency between two instruction nodes.
- *
- * The @after node will be scheduled after @before. We will try to
- * schedule it @latency cycles after @before, but no guarantees there.
- */
-void
-instruction_scheduler::add_dep(schedule_node *before, schedule_node *after,
- int latency)
-{
- if (!before || !after)
- return;
-
- assert(before != after);
-
- for (int i = 0; i < before->child_count; i++) {
- if (before->children[i] == after) {
- before->child_latency[i] = MAX2(before->child_latency[i], latency);
- return;
- }
- }
-
- if (before->child_array_size <= before->child_count) {
- if (before->child_array_size < 16)
- before->child_array_size = 16;
- else
- before->child_array_size *= 2;
-
- before->children = reralloc(mem_ctx, before->children,
- schedule_node *,
- before->child_array_size);
- before->child_latency = reralloc(mem_ctx, before->child_latency,
- int, before->child_array_size);
- }
-
- before->children[before->child_count] = after;
- before->child_latency[before->child_count] = latency;
- before->child_count++;
- after->parent_count++;
-}
-
-void
-instruction_scheduler::add_dep(schedule_node *before, schedule_node *after)
-{
- if (!before)
- return;
-
- add_dep(before, after, before->latency);
-}
-
-/**
- * Sometimes we really want this node to execute after everything that
- * was before it and before everything that followed it. This adds
- * the deps to do so.
- */
-void
-instruction_scheduler::add_barrier_deps(schedule_node *n)
-{
- schedule_node *prev = (schedule_node *)n->prev;
- schedule_node *next = (schedule_node *)n->next;
-
- if (prev) {
- while (!prev->is_head_sentinel()) {
- add_dep(prev, n, 0);
- prev = (schedule_node *)prev->prev;
- }
- }
-
- if (next) {
- while (!next->is_tail_sentinel()) {
- add_dep(n, next, 0);
- next = (schedule_node *)next->next;
- }
- }
-}
-
-/* instruction scheduling needs to be aware of when an MRF write
- * actually writes 2 MRFs.
- */
-bool
-instruction_scheduler::is_compressed(fs_inst *inst)
-{
- return (v->dispatch_width == 16 &&
- !inst->force_uncompressed &&
- !inst->force_sechalf);
-}
-
-void
-instruction_scheduler::calculate_deps()
-{
- /* Pre-register-allocation, this tracks the last write per VGRF (so
- * different reg_offsets within it can interfere when they shouldn't).
- * After register allocation, reg_offsets are gone and we track individual
- * GRF registers.
- */
- schedule_node *last_grf_write[grf_count];
- schedule_node *last_mrf_write[BRW_MAX_MRF];
- schedule_node *last_conditional_mod[2] = { NULL, NULL };
- /* Fixed HW registers are assumed to be separate from the virtual
- * GRFs, so they can be tracked separately. We don't really write
- * to fixed GRFs much, so don't bother tracking them on a more
- * granular level.
- */
- schedule_node *last_fixed_grf_write = NULL;
- int reg_width = v->dispatch_width / 8;
-
- /* The last instruction always needs to still be the last
- * instruction. Either it's flow control (IF, ELSE, ENDIF, DO,
- * WHILE) and scheduling other things after it would disturb the
- * basic block, or it's FB_WRITE and we should do a better job at
- * dead code elimination anyway.
- */
- schedule_node *last = (schedule_node *)instructions.get_tail();
- add_barrier_deps(last);
-
- memset(last_grf_write, 0, sizeof(last_grf_write));
- memset(last_mrf_write, 0, sizeof(last_mrf_write));
-
- /* top-to-bottom dependencies: RAW and WAW. */
- foreach_list(node, &instructions) {
- schedule_node *n = (schedule_node *)node;
- fs_inst *inst = n->inst;
-
- if (inst->opcode == FS_OPCODE_PLACEHOLDER_HALT)
- add_barrier_deps(n);
-
- /* read-after-write deps. */
- for (int i = 0; i < 3; i++) {
- if (inst->src[i].file == GRF) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- add_dep(last_grf_write[inst->src[i].reg + r], n);
- } else {
- add_dep(last_grf_write[inst->src[i].reg], n);
- }
- } else if (inst->src[i].file == HW_REG &&
- (inst->src[i].fixed_hw_reg.file ==
- BRW_GENERAL_REGISTER_FILE)) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- add_dep(last_grf_write[inst->src[i].fixed_hw_reg.nr + r], n);
- } else {
- add_dep(last_fixed_grf_write, n);
- }
- } else if (inst->src[i].file != BAD_FILE &&
- inst->src[i].file != IMM &&
- inst->src[i].file != UNIFORM) {
- assert(inst->src[i].file != MRF);
- add_barrier_deps(n);
- }
- }
-
- for (int i = 0; i < inst->mlen; i++) {
- /* It looks like the MRF regs are released in the send
- * instruction once it's sent, not when the result comes
- * back.
- */
- add_dep(last_mrf_write[inst->base_mrf + i], n);
- }
-
- if (inst->predicate) {
- add_dep(last_conditional_mod[inst->flag_subreg], n);
- }
-
- /* write-after-write deps. */
- if (inst->dst.file == GRF) {
- if (post_reg_alloc) {
- for (int r = 0; r < inst->regs_written * reg_width; r++) {
- add_dep(last_grf_write[inst->dst.reg + r], n);
- last_grf_write[inst->dst.reg + r] = n;
- }
- } else {
- add_dep(last_grf_write[inst->dst.reg], n);
- last_grf_write[inst->dst.reg] = n;
- }
- } else if (inst->dst.file == MRF) {
- int reg = inst->dst.reg & ~BRW_MRF_COMPR4;
-
- add_dep(last_mrf_write[reg], n);
- last_mrf_write[reg] = n;
- if (is_compressed(inst)) {
- if (inst->dst.reg & BRW_MRF_COMPR4)
- reg += 4;
- else
- reg++;
- add_dep(last_mrf_write[reg], n);
- last_mrf_write[reg] = n;
- }
- } else if (inst->dst.file == HW_REG &&
- inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- last_grf_write[inst->dst.fixed_hw_reg.nr + r] = n;
- } else {
- last_fixed_grf_write = n;
- }
- } else if (inst->dst.file != BAD_FILE) {
- add_barrier_deps(n);
- }
-
- if (inst->mlen > 0) {
- for (int i = 0; i < v->implied_mrf_writes(inst); i++) {
- add_dep(last_mrf_write[inst->base_mrf + i], n);
- last_mrf_write[inst->base_mrf + i] = n;
- }
- }
-
- /* Treat FS_OPCODE_MOV_DISPATCH_TO_FLAGS as though it had a
- * conditional_mod, because it sets the flag register.
- */
- if (inst->conditional_mod ||
- inst->opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS) {
- add_dep(last_conditional_mod[inst->flag_subreg], n, 0);
- last_conditional_mod[inst->flag_subreg] = n;
- }
- }
-
- /* bottom-to-top dependencies: WAR */
- memset(last_grf_write, 0, sizeof(last_grf_write));
- memset(last_mrf_write, 0, sizeof(last_mrf_write));
- memset(last_conditional_mod, 0, sizeof(last_conditional_mod));
- last_fixed_grf_write = NULL;
-
- exec_node *node;
- exec_node *prev;
- for (node = instructions.get_tail(), prev = node->prev;
- !node->is_head_sentinel();
- node = prev, prev = node->prev) {
- schedule_node *n = (schedule_node *)node;
- fs_inst *inst = n->inst;
-
- /* write-after-read deps. */
- for (int i = 0; i < 3; i++) {
- if (inst->src[i].file == GRF) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- add_dep(n, last_grf_write[inst->src[i].reg + r]);
- } else {
- add_dep(n, last_grf_write[inst->src[i].reg]);
- }
- } else if (inst->src[i].file == HW_REG &&
- (inst->src[i].fixed_hw_reg.file ==
- BRW_GENERAL_REGISTER_FILE)) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- add_dep(n, last_grf_write[inst->src[i].fixed_hw_reg.nr + r]);
- } else {
- add_dep(n, last_fixed_grf_write);
- }
- } else if (inst->src[i].file != BAD_FILE &&
- inst->src[i].file != IMM &&
- inst->src[i].file != UNIFORM) {
- assert(inst->src[i].file != MRF);
- add_barrier_deps(n);
- }
- }
-
- for (int i = 0; i < inst->mlen; i++) {
- /* It looks like the MRF regs are released in the send
- * instruction once it's sent, not when the result comes
- * back.
- */
- add_dep(n, last_mrf_write[inst->base_mrf + i], 2);
- }
-
- if (inst->predicate) {
- add_dep(n, last_conditional_mod[inst->flag_subreg]);
- }
-
- /* Update the things this instruction wrote, so earlier reads
- * can mark this as WAR dependency.
- */
- if (inst->dst.file == GRF) {
- if (post_reg_alloc) {
- for (int r = 0; r < inst->regs_written * reg_width; r++)
- last_grf_write[inst->dst.reg + r] = n;
- } else {
- last_grf_write[inst->dst.reg] = n;
- }
- } else if (inst->dst.file == MRF) {
- int reg = inst->dst.reg & ~BRW_MRF_COMPR4;
-
- last_mrf_write[reg] = n;
-
- if (is_compressed(inst)) {
- if (inst->dst.reg & BRW_MRF_COMPR4)
- reg += 4;
- else
- reg++;
-
- last_mrf_write[reg] = n;
- }
- } else if (inst->dst.file == HW_REG &&
- inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) {
- if (post_reg_alloc) {
- for (int r = 0; r < reg_width; r++)
- last_grf_write[inst->dst.fixed_hw_reg.nr + r] = n;
- } else {
- last_fixed_grf_write = n;
- }
- } else if (inst->dst.file != BAD_FILE) {
- add_barrier_deps(n);
- }
-
- if (inst->mlen > 0) {
- for (int i = 0; i < v->implied_mrf_writes(inst); i++) {
- last_mrf_write[inst->base_mrf + i] = n;
- }
- }
-
- /* Treat FS_OPCODE_MOV_DISPATCH_TO_FLAGS as though it had a
- * conditional_mod, because it sets the flag register.
- */
- if (inst->conditional_mod ||
- inst->opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS) {
- last_conditional_mod[inst->flag_subreg] = n;
- }
- }
-}
-
-void
-instruction_scheduler::schedule_instructions(fs_inst *next_block_header)
-{
- int time = 0;
-
- /* Remove non-DAG heads from the list. */
- foreach_list_safe(node, &instructions) {
- schedule_node *n = (schedule_node *)node;
- if (n->parent_count != 0)
- n->remove();
- }
-
- while (!instructions.is_empty()) {
- schedule_node *chosen = NULL;
- int chosen_time = 0;
-
- if (post_reg_alloc) {
- /* Of the instructions closest ready to execute or the closest to
- * being ready, choose the oldest one.
- */
- foreach_list(node, &instructions) {
- schedule_node *n = (schedule_node *)node;
-
- if (!chosen || n->unblocked_time < chosen_time) {
- chosen = n;
- chosen_time = n->unblocked_time;
- }
- }
- } else {
- /* Before register allocation, we don't care about the latencies of
- * instructions. All we care about is reducing live intervals of
- * variables so that we can avoid register spilling, or get 16-wide
- * shaders which naturally do a better job of hiding instruction
- * latency.
- *
- * To do so, schedule our instructions in a roughly LIFO/depth-first
- * order: when new instructions become available as a result of
- * scheduling something, choose those first so that our result
- * hopefully is consumed quickly.
- *
- * The exception is messages that generate more than one result
- * register (AKA texturing). In those cases, the LIFO search would
- * normally tend to choose them quickly (because scheduling the
- * previous message not only unblocked the children using its result,
- * but also the MRF setup for the next sampler message, which in turn
- * unblocks the next sampler message).
- */
- for (schedule_node *node = (schedule_node *)instructions.get_tail();
- node != instructions.get_head()->prev;
- node = (schedule_node *)node->prev) {
- schedule_node *n = (schedule_node *)node;
-
- chosen = n;
- if (chosen->inst->regs_written <= 1)
- break;
- }
-
- chosen_time = chosen->unblocked_time;
- }
-
- /* Schedule this instruction. */
- assert(chosen);
- chosen->remove();
- next_block_header->insert_before(chosen->inst);
- instructions_to_schedule--;
-
- /* Bump the clock. Instructions in gen hardware are handled one simd4
- * vector at a time, with 1 cycle per vector dispatched. Thus 8-wide
- * pixel shaders take 2 cycles to dispatch and 16-wide (compressed)
- * instructions take 4.
- */
- if (is_compressed(chosen->inst))
- time += 4;
- else
- time += 2;
-
- /* If we expected a delay for scheduling, then bump the clock to reflect
- * that as well. In reality, the hardware will switch to another
- * hyperthread and may not return to dispatching our thread for a while
- * even after we're unblocked.
- */
- time = MAX2(time, chosen_time);
-
- if (debug) {
- printf("clock %4d, scheduled: ", time);
- v->dump_instruction(chosen->inst);
- }
-
- /* Now that we've scheduled a new instruction, some of its
- * children can be promoted to the list of instructions ready to
- * be scheduled. Update the children's unblocked time for this
- * DAG edge as we do so.
- */
- for (int i = 0; i < chosen->child_count; i++) {
- schedule_node *child = chosen->children[i];
-
- child->unblocked_time = MAX2(child->unblocked_time,
- time + chosen->child_latency[i]);
-
- child->parent_count--;
- if (child->parent_count == 0) {
- if (debug) {
- printf("now available: ");
- v->dump_instruction(child->inst);
- }
- instructions.push_tail(child);
- }
- }
-
- /* Shared resource: the mathbox. There's one mathbox per EU on Gen6+
- * but it's more limited pre-gen6, so if we send something off to it then
- * the next math instruction isn't going to make progress until the first
- * is done.
- */
- if (chosen->inst->is_math()) {
- foreach_list(node, &instructions) {
- schedule_node *n = (schedule_node *)node;
-
- if (n->inst->is_math())
- n->unblocked_time = MAX2(n->unblocked_time,
- time + chosen->latency);
- }
- }
- }
-
- if (unlikely(INTEL_DEBUG & DEBUG_WM) && post_reg_alloc) {
- printf("fs%d estimated execution time: %d cycles\n",
- v->dispatch_width, time);
- }
-
- assert(instructions_to_schedule == 0);
-}
-
-void
-fs_visitor::schedule_instructions(bool post_reg_alloc)
-{
- fs_inst *next_block_header = (fs_inst *)instructions.head;
-
- int grf_count;
- if (post_reg_alloc)
- grf_count = grf_used;
- else
- grf_count = virtual_grf_count;
-
- if (debug) {
- printf("\nInstructions before scheduling (reg_alloc %d)\n", post_reg_alloc);
- dump_instructions();
- }
-
- instruction_scheduler sched(this, mem_ctx, grf_count, post_reg_alloc);
-
- while (!next_block_header->is_tail_sentinel()) {
- /* Add things to be scheduled until we get to a new BB. */
- while (!next_block_header->is_tail_sentinel()) {
- fs_inst *inst = next_block_header;
- next_block_header = (fs_inst *)next_block_header->next;
-
- sched.add_inst(inst);
- if (inst->is_control_flow())
- break;
- }
- sched.calculate_deps();
- sched.schedule_instructions(next_block_header);
- }
-
- if (debug) {
- printf("\nInstructions after scheduling (reg_alloc %d)\n", post_reg_alloc);
- dump_instructions();
- }
-
- this->live_intervals_valid = false;
-}
--- /dev/null
+/*
+ * Copyright © 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Eric Anholt <eric@anholt.net>
+ *
+ */
+
+#include "brw_fs.h"
+#include "glsl/glsl_types.h"
+#include "glsl/ir_optimization.h"
+#include "glsl/ir_print_visitor.h"
+
+/** @file brw_fs_schedule_instructions.cpp
+ *
+ * List scheduling of FS instructions.
+ *
+ * The basic model of the list scheduler is to take a basic block,
+ * compute a DAG of the dependencies (RAW ordering with latency, WAW
+ * ordering with latency, WAR ordering), and make a list of the DAG heads.
+ * Heuristically pick a DAG head, then put all the children that are
+ * now DAG heads into the list of things to schedule.
+ *
+ * The heuristic is the important part. We're trying to be cheap,
+ * since actually computing the optimal scheduling is NP complete.
+ * What we do is track a "current clock". When we schedule a node, we
+ * update the earliest-unblocked clock time of its children, and
+ * increment the clock. Then, when trying to schedule, we just pick
+ * the earliest-unblocked instruction to schedule.
+ *
+ * Note that often there will be many things which could execute
+ * immediately, and there are a range of heuristic options to choose
+ * from in picking among those.
+ */
+
+static bool debug = false;
+
+class schedule_node : public exec_node
+{
+public:
+ schedule_node(fs_inst *inst, const struct intel_context *intel)
+ {
+ this->inst = inst;
+ this->child_array_size = 0;
+ this->children = NULL;
+ this->child_latency = NULL;
+ this->child_count = 0;
+ this->parent_count = 0;
+ this->unblocked_time = 0;
+
+ /* We can't measure Gen6 timings directly but expect them to be much
+ * closer to Gen7 than Gen4.
+ */
+ if (intel->gen >= 6)
+ set_latency_gen7(intel->is_haswell);
+ else
+ set_latency_gen4();
+ }
+
+ void set_latency_gen4();
+ void set_latency_gen7(bool is_haswell);
+
+ fs_inst *inst;
+ schedule_node **children;
+ int *child_latency;
+ int child_count;
+ int parent_count;
+ int child_array_size;
+ int unblocked_time;
+ int latency;
+};
+
+void
+schedule_node::set_latency_gen4()
+{
+ int chans = 8;
+ int math_latency = 22;
+
+ switch (inst->opcode) {
+ case SHADER_OPCODE_RCP:
+ this->latency = 1 * chans * math_latency;
+ break;
+ case SHADER_OPCODE_RSQ:
+ this->latency = 2 * chans * math_latency;
+ break;
+ case SHADER_OPCODE_INT_QUOTIENT:
+ case SHADER_OPCODE_SQRT:
+ case SHADER_OPCODE_LOG2:
+ /* full precision log. partial is 2. */
+ this->latency = 3 * chans * math_latency;
+ break;
+ case SHADER_OPCODE_INT_REMAINDER:
+ case SHADER_OPCODE_EXP2:
+ /* full precision. partial is 3, same throughput. */
+ this->latency = 4 * chans * math_latency;
+ break;
+ case SHADER_OPCODE_POW:
+ this->latency = 8 * chans * math_latency;
+ break;
+ case SHADER_OPCODE_SIN:
+ case SHADER_OPCODE_COS:
+ /* minimum latency, max is 12 rounds. */
+ this->latency = 5 * chans * math_latency;
+ break;
+ default:
+ this->latency = 2;
+ break;
+ }
+}
+
+void
+schedule_node::set_latency_gen7(bool is_haswell)
+{
+ switch (inst->opcode) {
+ case BRW_OPCODE_MAD:
+ /* 2 cycles
+ * (since the last two src operands are in different register banks):
+ * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
+ *
+ * 3 cycles on IVB, 4 on HSW
+ * (since the last two src operands are in the same register bank):
+ * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
+ *
+ * 18 cycles on IVB, 16 on HSW
+ * (since the last two src operands are in different register banks):
+ * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
+ * mov(8) null g4<4,5,1>F { align16 WE_normal 1Q };
+ *
+ * 20 cycles on IVB, 18 on HSW
+ * (since the last two src operands are in the same register bank):
+ * mad(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
+ * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
+ */
+
+ /* Our register allocator doesn't know about register banks, so use the
+ * higher latency.
+ */
+ latency = is_haswell ? 16 : 18;
+ break;
+
+ case BRW_OPCODE_LRP:
+ /* 2 cycles
+ * (since the last two src operands are in different register banks):
+ * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
+ *
+ * 3 cycles on IVB, 4 on HSW
+ * (since the last two src operands are in the same register bank):
+ * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
+ *
+ * 16 cycles on IVB, 14 on HSW
+ * (since the last two src operands are in different register banks):
+ * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g3.1<4,1,1>F.x { align16 WE_normal 1Q };
+ * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
+ *
+ * 16 cycles
+ * (since the last two src operands are in the same register bank):
+ * lrp(8) g4<1>F g2.2<4,1,1>F.x g2<4,1,1>F.x g2.1<4,1,1>F.x { align16 WE_normal 1Q };
+ * mov(8) null g4<4,4,1>F { align16 WE_normal 1Q };
+ */
+
+ /* Our register allocator doesn't know about register banks, so use the
+ * higher latency.
+ */
+ latency = 14;
+ break;
+
+ case SHADER_OPCODE_RCP:
+ case SHADER_OPCODE_RSQ:
+ case SHADER_OPCODE_SQRT:
+ case SHADER_OPCODE_LOG2:
+ case SHADER_OPCODE_EXP2:
+ case SHADER_OPCODE_SIN:
+ case SHADER_OPCODE_COS:
+ /* 2 cycles:
+ * math inv(8) g4<1>F g2<0,1,0>F null { align1 WE_normal 1Q };
+ *
+ * 18 cycles:
+ * math inv(8) g4<1>F g2<0,1,0>F null { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * Same for exp2, log2, rsq, sqrt, sin, cos.
+ */
+ latency = is_haswell ? 14 : 16;
+ break;
+
+ case SHADER_OPCODE_POW:
+ /* 2 cycles:
+ * math pow(8) g4<1>F g2<0,1,0>F g2.1<0,1,0>F { align1 WE_normal 1Q };
+ *
+ * 26 cycles:
+ * math pow(8) g4<1>F g2<0,1,0>F g2.1<0,1,0>F { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ */
+ latency = is_haswell ? 22 : 24;
+ break;
+
+ case SHADER_OPCODE_TEX:
+ case SHADER_OPCODE_TXD:
+ case SHADER_OPCODE_TXF:
+ case SHADER_OPCODE_TXL:
+ /* 18 cycles:
+ * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
+ * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
+ * send(8) g4<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ *
+ * 697 +/-49 cycles (min 610, n=26):
+ * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
+ * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
+ * send(8) g4<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * So the latency on our first texture load of the batchbuffer takes
+ * ~700 cycles, since the caches are cold at that point.
+ *
+ * 840 +/- 92 cycles (min 720, n=25):
+ * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
+ * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
+ * send(8) g4<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ * send(8) g4<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * On the second load, it takes just an extra ~140 cycles, and after
+ * accounting for the 14 cycles of the MOV's latency, that makes ~130.
+ *
+ * 683 +/- 49 cycles (min = 602, n=47):
+ * mov(8) g115<1>F 0F { align1 WE_normal 1Q };
+ * mov(8) g114<1>F 0F { align1 WE_normal 1Q };
+ * send(8) g4<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ * send(8) g50<1>UW g114<8,8,1>F
+ * sampler (10, 0, 0, 1) mlen 2 rlen 4 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * The unit appears to be pipelined, since this matches up with the
+ * cache-cold case, despite there being two loads here. If you replace
+ * the g4 in the MOV to null with g50, it's still 693 +/- 52 (n=39).
+ *
+ * So, take some number between the cache-hot 140 cycles and the
+ * cache-cold 700 cycles. No particular tuning was done on this.
+ *
+ * I haven't done significant testing of the non-TEX opcodes. TXL at
+ * least looked about the same as TEX.
+ */
+ latency = 200;
+ break;
+
+ case SHADER_OPCODE_TXS:
+ /* Testing textureSize(sampler2D, 0), one load was 420 +/- 41
+ * cycles (n=15):
+ * mov(8) g114<1>UD 0D { align1 WE_normal 1Q };
+ * send(8) g6<1>UW g114<8,8,1>F
+ * sampler (10, 0, 10, 1) mlen 1 rlen 4 { align1 WE_normal 1Q };
+ * mov(16) g6<1>F g6<8,8,1>D { align1 WE_normal 1Q };
+ *
+ *
+ * Two loads was 535 +/- 30 cycles (n=19):
+ * mov(16) g114<1>UD 0D { align1 WE_normal 1H };
+ * send(16) g6<1>UW g114<8,8,1>F
+ * sampler (10, 0, 10, 2) mlen 2 rlen 8 { align1 WE_normal 1H };
+ * mov(16) g114<1>UD 0D { align1 WE_normal 1H };
+ * mov(16) g6<1>F g6<8,8,1>D { align1 WE_normal 1H };
+ * send(16) g8<1>UW g114<8,8,1>F
+ * sampler (10, 0, 10, 2) mlen 2 rlen 8 { align1 WE_normal 1H };
+ * mov(16) g8<1>F g8<8,8,1>D { align1 WE_normal 1H };
+ * add(16) g6<1>F g6<8,8,1>F g8<8,8,1>F { align1 WE_normal 1H };
+ *
+ * Since the only caches that should matter are just the
+ * instruction/state cache containing the surface state, assume that we
+ * always have hot caches.
+ */
+ latency = 100;
+ break;
+
+ case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD:
+ case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD:
+ /* testing using varying-index pull constants:
+ *
+ * 16 cycles:
+ * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
+ * send(8) g4<1>F g4<8,8,1>D
+ * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
+ *
+ * ~480 cycles:
+ * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
+ * send(8) g4<1>F g4<8,8,1>D
+ * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * ~620 cycles:
+ * mov(8) g4<1>D g2.1<0,1,0>F { align1 WE_normal 1Q };
+ * send(8) g4<1>F g4<8,8,1>D
+ * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ * send(8) g4<1>F g4<8,8,1>D
+ * data (9, 2, 3) mlen 1 rlen 1 { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ *
+ * So, if it's cache-hot, it's about 140. If it's cache cold, it's
+ * about 460. We expect to mostly be cache hot, so pick something more
+ * in that direction.
+ */
+ latency = 200;
+ break;
+
+ default:
+ /* 2 cycles:
+ * mul(8) g4<1>F g2<0,1,0>F 0.5F { align1 WE_normal 1Q };
+ *
+ * 16 cycles:
+ * mul(8) g4<1>F g2<0,1,0>F 0.5F { align1 WE_normal 1Q };
+ * mov(8) null g4<8,8,1>F { align1 WE_normal 1Q };
+ */
+ latency = 14;
+ break;
+ }
+}
+
+class instruction_scheduler {
+public:
+ instruction_scheduler(fs_visitor *v, void *mem_ctx, int grf_count,
+ bool post_reg_alloc)
+ {
+ this->v = v;
+ this->mem_ctx = ralloc_context(mem_ctx);
+ this->grf_count = grf_count;
+ this->instructions.make_empty();
+ this->instructions_to_schedule = 0;
+ this->post_reg_alloc = post_reg_alloc;
+ }
+
+ ~instruction_scheduler()
+ {
+ ralloc_free(this->mem_ctx);
+ }
+ void add_barrier_deps(schedule_node *n);
+ void add_dep(schedule_node *before, schedule_node *after, int latency);
+ void add_dep(schedule_node *before, schedule_node *after);
+
+ void add_inst(fs_inst *inst);
+ void calculate_deps();
+ void schedule_instructions(fs_inst *next_block_header);
+
+ bool is_compressed(fs_inst *inst);
+
+ void *mem_ctx;
+
+ bool post_reg_alloc;
+ int instructions_to_schedule;
+ int grf_count;
+ exec_list instructions;
+ fs_visitor *v;
+};
+
+void
+instruction_scheduler::add_inst(fs_inst *inst)
+{
+ schedule_node *n = new(mem_ctx) schedule_node(inst, v->intel);
+
+ assert(!inst->is_head_sentinel());
+ assert(!inst->is_tail_sentinel());
+
+ this->instructions_to_schedule++;
+
+ inst->remove();
+ instructions.push_tail(n);
+}
+
+/**
+ * Add a dependency between two instruction nodes.
+ *
+ * The @after node will be scheduled after @before. We will try to
+ * schedule it @latency cycles after @before, but no guarantees there.
+ */
+void
+instruction_scheduler::add_dep(schedule_node *before, schedule_node *after,
+ int latency)
+{
+ if (!before || !after)
+ return;
+
+ assert(before != after);
+
+ for (int i = 0; i < before->child_count; i++) {
+ if (before->children[i] == after) {
+ before->child_latency[i] = MAX2(before->child_latency[i], latency);
+ return;
+ }
+ }
+
+ if (before->child_array_size <= before->child_count) {
+ if (before->child_array_size < 16)
+ before->child_array_size = 16;
+ else
+ before->child_array_size *= 2;
+
+ before->children = reralloc(mem_ctx, before->children,
+ schedule_node *,
+ before->child_array_size);
+ before->child_latency = reralloc(mem_ctx, before->child_latency,
+ int, before->child_array_size);
+ }
+
+ before->children[before->child_count] = after;
+ before->child_latency[before->child_count] = latency;
+ before->child_count++;
+ after->parent_count++;
+}
+
+void
+instruction_scheduler::add_dep(schedule_node *before, schedule_node *after)
+{
+ if (!before)
+ return;
+
+ add_dep(before, after, before->latency);
+}
+
+/**
+ * Sometimes we really want this node to execute after everything that
+ * was before it and before everything that followed it. This adds
+ * the deps to do so.
+ */
+void
+instruction_scheduler::add_barrier_deps(schedule_node *n)
+{
+ schedule_node *prev = (schedule_node *)n->prev;
+ schedule_node *next = (schedule_node *)n->next;
+
+ if (prev) {
+ while (!prev->is_head_sentinel()) {
+ add_dep(prev, n, 0);
+ prev = (schedule_node *)prev->prev;
+ }
+ }
+
+ if (next) {
+ while (!next->is_tail_sentinel()) {
+ add_dep(n, next, 0);
+ next = (schedule_node *)next->next;
+ }
+ }
+}
+
+/* instruction scheduling needs to be aware of when an MRF write
+ * actually writes 2 MRFs.
+ */
+bool
+instruction_scheduler::is_compressed(fs_inst *inst)
+{
+ return (v->dispatch_width == 16 &&
+ !inst->force_uncompressed &&
+ !inst->force_sechalf);
+}
+
+void
+instruction_scheduler::calculate_deps()
+{
+ /* Pre-register-allocation, this tracks the last write per VGRF (so
+ * different reg_offsets within it can interfere when they shouldn't).
+ * After register allocation, reg_offsets are gone and we track individual
+ * GRF registers.
+ */
+ schedule_node *last_grf_write[grf_count];
+ schedule_node *last_mrf_write[BRW_MAX_MRF];
+ schedule_node *last_conditional_mod[2] = { NULL, NULL };
+ /* Fixed HW registers are assumed to be separate from the virtual
+ * GRFs, so they can be tracked separately. We don't really write
+ * to fixed GRFs much, so don't bother tracking them on a more
+ * granular level.
+ */
+ schedule_node *last_fixed_grf_write = NULL;
+ int reg_width = v->dispatch_width / 8;
+
+ /* The last instruction always needs to still be the last
+ * instruction. Either it's flow control (IF, ELSE, ENDIF, DO,
+ * WHILE) and scheduling other things after it would disturb the
+ * basic block, or it's FB_WRITE and we should do a better job at
+ * dead code elimination anyway.
+ */
+ schedule_node *last = (schedule_node *)instructions.get_tail();
+ add_barrier_deps(last);
+
+ memset(last_grf_write, 0, sizeof(last_grf_write));
+ memset(last_mrf_write, 0, sizeof(last_mrf_write));
+
+ /* top-to-bottom dependencies: RAW and WAW. */
+ foreach_list(node, &instructions) {
+ schedule_node *n = (schedule_node *)node;
+ fs_inst *inst = n->inst;
+
+ if (inst->opcode == FS_OPCODE_PLACEHOLDER_HALT)
+ add_barrier_deps(n);
+
+ /* read-after-write deps. */
+ for (int i = 0; i < 3; i++) {
+ if (inst->src[i].file == GRF) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ add_dep(last_grf_write[inst->src[i].reg + r], n);
+ } else {
+ add_dep(last_grf_write[inst->src[i].reg], n);
+ }
+ } else if (inst->src[i].file == HW_REG &&
+ (inst->src[i].fixed_hw_reg.file ==
+ BRW_GENERAL_REGISTER_FILE)) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ add_dep(last_grf_write[inst->src[i].fixed_hw_reg.nr + r], n);
+ } else {
+ add_dep(last_fixed_grf_write, n);
+ }
+ } else if (inst->src[i].file != BAD_FILE &&
+ inst->src[i].file != IMM &&
+ inst->src[i].file != UNIFORM) {
+ assert(inst->src[i].file != MRF);
+ add_barrier_deps(n);
+ }
+ }
+
+ for (int i = 0; i < inst->mlen; i++) {
+ /* It looks like the MRF regs are released in the send
+ * instruction once it's sent, not when the result comes
+ * back.
+ */
+ add_dep(last_mrf_write[inst->base_mrf + i], n);
+ }
+
+ if (inst->predicate) {
+ add_dep(last_conditional_mod[inst->flag_subreg], n);
+ }
+
+ /* write-after-write deps. */
+ if (inst->dst.file == GRF) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < inst->regs_written * reg_width; r++) {
+ add_dep(last_grf_write[inst->dst.reg + r], n);
+ last_grf_write[inst->dst.reg + r] = n;
+ }
+ } else {
+ add_dep(last_grf_write[inst->dst.reg], n);
+ last_grf_write[inst->dst.reg] = n;
+ }
+ } else if (inst->dst.file == MRF) {
+ int reg = inst->dst.reg & ~BRW_MRF_COMPR4;
+
+ add_dep(last_mrf_write[reg], n);
+ last_mrf_write[reg] = n;
+ if (is_compressed(inst)) {
+ if (inst->dst.reg & BRW_MRF_COMPR4)
+ reg += 4;
+ else
+ reg++;
+ add_dep(last_mrf_write[reg], n);
+ last_mrf_write[reg] = n;
+ }
+ } else if (inst->dst.file == HW_REG &&
+ inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ last_grf_write[inst->dst.fixed_hw_reg.nr + r] = n;
+ } else {
+ last_fixed_grf_write = n;
+ }
+ } else if (inst->dst.file != BAD_FILE) {
+ add_barrier_deps(n);
+ }
+
+ if (inst->mlen > 0) {
+ for (int i = 0; i < v->implied_mrf_writes(inst); i++) {
+ add_dep(last_mrf_write[inst->base_mrf + i], n);
+ last_mrf_write[inst->base_mrf + i] = n;
+ }
+ }
+
+ /* Treat FS_OPCODE_MOV_DISPATCH_TO_FLAGS as though it had a
+ * conditional_mod, because it sets the flag register.
+ */
+ if (inst->conditional_mod ||
+ inst->opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS) {
+ add_dep(last_conditional_mod[inst->flag_subreg], n, 0);
+ last_conditional_mod[inst->flag_subreg] = n;
+ }
+ }
+
+ /* bottom-to-top dependencies: WAR */
+ memset(last_grf_write, 0, sizeof(last_grf_write));
+ memset(last_mrf_write, 0, sizeof(last_mrf_write));
+ memset(last_conditional_mod, 0, sizeof(last_conditional_mod));
+ last_fixed_grf_write = NULL;
+
+ exec_node *node;
+ exec_node *prev;
+ for (node = instructions.get_tail(), prev = node->prev;
+ !node->is_head_sentinel();
+ node = prev, prev = node->prev) {
+ schedule_node *n = (schedule_node *)node;
+ fs_inst *inst = n->inst;
+
+ /* write-after-read deps. */
+ for (int i = 0; i < 3; i++) {
+ if (inst->src[i].file == GRF) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ add_dep(n, last_grf_write[inst->src[i].reg + r]);
+ } else {
+ add_dep(n, last_grf_write[inst->src[i].reg]);
+ }
+ } else if (inst->src[i].file == HW_REG &&
+ (inst->src[i].fixed_hw_reg.file ==
+ BRW_GENERAL_REGISTER_FILE)) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ add_dep(n, last_grf_write[inst->src[i].fixed_hw_reg.nr + r]);
+ } else {
+ add_dep(n, last_fixed_grf_write);
+ }
+ } else if (inst->src[i].file != BAD_FILE &&
+ inst->src[i].file != IMM &&
+ inst->src[i].file != UNIFORM) {
+ assert(inst->src[i].file != MRF);
+ add_barrier_deps(n);
+ }
+ }
+
+ for (int i = 0; i < inst->mlen; i++) {
+ /* It looks like the MRF regs are released in the send
+ * instruction once it's sent, not when the result comes
+ * back.
+ */
+ add_dep(n, last_mrf_write[inst->base_mrf + i], 2);
+ }
+
+ if (inst->predicate) {
+ add_dep(n, last_conditional_mod[inst->flag_subreg]);
+ }
+
+ /* Update the things this instruction wrote, so earlier reads
+ * can mark this as WAR dependency.
+ */
+ if (inst->dst.file == GRF) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < inst->regs_written * reg_width; r++)
+ last_grf_write[inst->dst.reg + r] = n;
+ } else {
+ last_grf_write[inst->dst.reg] = n;
+ }
+ } else if (inst->dst.file == MRF) {
+ int reg = inst->dst.reg & ~BRW_MRF_COMPR4;
+
+ last_mrf_write[reg] = n;
+
+ if (is_compressed(inst)) {
+ if (inst->dst.reg & BRW_MRF_COMPR4)
+ reg += 4;
+ else
+ reg++;
+
+ last_mrf_write[reg] = n;
+ }
+ } else if (inst->dst.file == HW_REG &&
+ inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) {
+ if (post_reg_alloc) {
+ for (int r = 0; r < reg_width; r++)
+ last_grf_write[inst->dst.fixed_hw_reg.nr + r] = n;
+ } else {
+ last_fixed_grf_write = n;
+ }
+ } else if (inst->dst.file != BAD_FILE) {
+ add_barrier_deps(n);
+ }
+
+ if (inst->mlen > 0) {
+ for (int i = 0; i < v->implied_mrf_writes(inst); i++) {
+ last_mrf_write[inst->base_mrf + i] = n;
+ }
+ }
+
+ /* Treat FS_OPCODE_MOV_DISPATCH_TO_FLAGS as though it had a
+ * conditional_mod, because it sets the flag register.
+ */
+ if (inst->conditional_mod ||
+ inst->opcode == FS_OPCODE_MOV_DISPATCH_TO_FLAGS) {
+ last_conditional_mod[inst->flag_subreg] = n;
+ }
+ }
+}
+
+void
+instruction_scheduler::schedule_instructions(fs_inst *next_block_header)
+{
+ int time = 0;
+
+ /* Remove non-DAG heads from the list. */
+ foreach_list_safe(node, &instructions) {
+ schedule_node *n = (schedule_node *)node;
+ if (n->parent_count != 0)
+ n->remove();
+ }
+
+ while (!instructions.is_empty()) {
+ schedule_node *chosen = NULL;
+ int chosen_time = 0;
+
+ if (post_reg_alloc) {
+ /* Of the instructions closest ready to execute or the closest to
+ * being ready, choose the oldest one.
+ */
+ foreach_list(node, &instructions) {
+ schedule_node *n = (schedule_node *)node;
+
+ if (!chosen || n->unblocked_time < chosen_time) {
+ chosen = n;
+ chosen_time = n->unblocked_time;
+ }
+ }
+ } else {
+ /* Before register allocation, we don't care about the latencies of
+ * instructions. All we care about is reducing live intervals of
+ * variables so that we can avoid register spilling, or get 16-wide
+ * shaders which naturally do a better job of hiding instruction
+ * latency.
+ *
+ * To do so, schedule our instructions in a roughly LIFO/depth-first
+ * order: when new instructions become available as a result of
+ * scheduling something, choose those first so that our result
+ * hopefully is consumed quickly.
+ *
+ * The exception is messages that generate more than one result
+ * register (AKA texturing). In those cases, the LIFO search would
+ * normally tend to choose them quickly (because scheduling the
+ * previous message not only unblocked the children using its result,
+ * but also the MRF setup for the next sampler message, which in turn
+ * unblocks the next sampler message).
+ */
+ for (schedule_node *node = (schedule_node *)instructions.get_tail();
+ node != instructions.get_head()->prev;
+ node = (schedule_node *)node->prev) {
+ schedule_node *n = (schedule_node *)node;
+
+ chosen = n;
+ if (chosen->inst->regs_written <= 1)
+ break;
+ }
+
+ chosen_time = chosen->unblocked_time;
+ }
+
+ /* Schedule this instruction. */
+ assert(chosen);
+ chosen->remove();
+ next_block_header->insert_before(chosen->inst);
+ instructions_to_schedule--;
+
+ /* Bump the clock. Instructions in gen hardware are handled one simd4
+ * vector at a time, with 1 cycle per vector dispatched. Thus 8-wide
+ * pixel shaders take 2 cycles to dispatch and 16-wide (compressed)
+ * instructions take 4.
+ */
+ if (is_compressed(chosen->inst))
+ time += 4;
+ else
+ time += 2;
+
+ /* If we expected a delay for scheduling, then bump the clock to reflect
+ * that as well. In reality, the hardware will switch to another
+ * hyperthread and may not return to dispatching our thread for a while
+ * even after we're unblocked.
+ */
+ time = MAX2(time, chosen_time);
+
+ if (debug) {
+ printf("clock %4d, scheduled: ", time);
+ v->dump_instruction(chosen->inst);
+ }
+
+ /* Now that we've scheduled a new instruction, some of its
+ * children can be promoted to the list of instructions ready to
+ * be scheduled. Update the children's unblocked time for this
+ * DAG edge as we do so.
+ */
+ for (int i = 0; i < chosen->child_count; i++) {
+ schedule_node *child = chosen->children[i];
+
+ child->unblocked_time = MAX2(child->unblocked_time,
+ time + chosen->child_latency[i]);
+
+ child->parent_count--;
+ if (child->parent_count == 0) {
+ if (debug) {
+ printf("now available: ");
+ v->dump_instruction(child->inst);
+ }
+ instructions.push_tail(child);
+ }
+ }
+
+ /* Shared resource: the mathbox. There's one mathbox per EU on Gen6+
+ * but it's more limited pre-gen6, so if we send something off to it then
+ * the next math instruction isn't going to make progress until the first
+ * is done.
+ */
+ if (chosen->inst->is_math()) {
+ foreach_list(node, &instructions) {
+ schedule_node *n = (schedule_node *)node;
+
+ if (n->inst->is_math())
+ n->unblocked_time = MAX2(n->unblocked_time,
+ time + chosen->latency);
+ }
+ }
+ }
+
+ if (unlikely(INTEL_DEBUG & DEBUG_WM) && post_reg_alloc) {
+ printf("fs%d estimated execution time: %d cycles\n",
+ v->dispatch_width, time);
+ }
+
+ assert(instructions_to_schedule == 0);
+}
+
+void
+fs_visitor::schedule_instructions(bool post_reg_alloc)
+{
+ fs_inst *next_block_header = (fs_inst *)instructions.head;
+
+ int grf_count;
+ if (post_reg_alloc)
+ grf_count = grf_used;
+ else
+ grf_count = virtual_grf_count;
+
+ if (debug) {
+ printf("\nInstructions before scheduling (reg_alloc %d)\n", post_reg_alloc);
+ dump_instructions();
+ }
+
+ instruction_scheduler sched(this, mem_ctx, grf_count, post_reg_alloc);
+
+ while (!next_block_header->is_tail_sentinel()) {
+ /* Add things to be scheduled until we get to a new BB. */
+ while (!next_block_header->is_tail_sentinel()) {
+ fs_inst *inst = next_block_header;
+ next_block_header = (fs_inst *)next_block_header->next;
+
+ sched.add_inst(inst);
+ if (inst->is_control_flow())
+ break;
+ }
+ sched.calculate_deps();
+ sched.schedule_instructions(next_block_header);
+ }
+
+ if (debug) {
+ printf("\nInstructions after scheduling (reg_alloc %d)\n", post_reg_alloc);
+ dump_instructions();
+ }
+
+ this->live_intervals_valid = false;
+}
projects / mesa.git / commitdiff