From: Eric Anholt Date: Sat, 1 Dec 2012 00:13:34 +0000 (-0800) Subject: i965/vs: Add instruction scheduling. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=573d8813fdbb116f4500d2044c56d80aab73ab7f;p=mesa.git i965/vs: Add instruction scheduling. While this is ignorant of dependency control, it's still good for a 0.39% +/- 0.08% performance improvement on GLBenchmark 2.7 (n=548) v2: Rewrite as a subclass of the base class for the FS instruction scheduler, inheriting the same latency information. Reviewed-by: Kenneth Graunke Reviewed-by: Matt Turner --- diff --git a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp index 94fdf3e066a..6a527544553 100644 --- a/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp +++ b/src/mesa/drivers/dri/i965/brw_schedule_instructions.cpp @@ -26,10 +26,13 @@ */ #include "brw_fs.h" +#include "brw_vec4.h" #include "glsl/glsl_types.h" #include "glsl/ir_optimization.h" #include "glsl/ir_print_visitor.h" +using namespace brw; + /** @file brw_fs_schedule_instructions.cpp * * List scheduling of FS instructions. @@ -297,6 +300,7 @@ schedule_node::set_latency_gen7(bool is_haswell) case FS_OPCODE_VARYING_PULL_CONSTANT_LOAD: case FS_OPCODE_UNIFORM_PULL_CONSTANT_LOAD: + case VS_OPCODE_PULL_CONSTANT_LOAD: /* testing using varying-index pull constants: * * 16 cycles: @@ -405,6 +409,23 @@ fs_instruction_scheduler::fs_instruction_scheduler(fs_visitor *v, { } +class vec4_instruction_scheduler : public instruction_scheduler +{ +public: + vec4_instruction_scheduler(vec4_visitor *v, int grf_count); + void calculate_deps(); + schedule_node *choose_instruction_to_schedule(); + int issue_time(backend_instruction *inst); + vec4_visitor *v; +}; + +vec4_instruction_scheduler::vec4_instruction_scheduler(vec4_visitor *v, + int grf_count) + : instruction_scheduler(v, grf_count, true), + v(v) +{ +} + void instruction_scheduler::add_inst(backend_instruction *inst) { @@ -739,6 +760,163 @@ fs_instruction_scheduler::calculate_deps() } } +void +vec4_instruction_scheduler::calculate_deps() +{ + schedule_node *last_grf_write[grf_count]; + schedule_node *last_mrf_write[BRW_MAX_MRF]; + schedule_node *last_conditional_mod = 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; + + /* 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 the EOT + * URB_WRITE and we should do a better job at dead code eliminating + * anything that could have been scheduled after it. + */ + 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; + vec4_instruction *inst = (vec4_instruction *)n->inst; + + /* read-after-write deps. */ + for (int i = 0; i < 3; i++) { + if (inst->src[i].file == GRF) { + 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)) { + 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) { + /* No reads from MRF, and ATTR is already translated away */ + assert(inst->src[i].file != MRF && + inst->src[i].file != ATTR); + 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) { + assert(last_conditional_mod); + add_dep(last_conditional_mod, n); + } + + /* write-after-write deps. */ + if (inst->dst.file == GRF) { + add_dep(last_grf_write[inst->dst.reg], n); + last_grf_write[inst->dst.reg] = n; + } else if (inst->dst.file == MRF) { + add_dep(last_mrf_write[inst->dst.reg], n); + last_mrf_write[inst->dst.reg] = n; + } else if (inst->dst.file == HW_REG && + inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) { + 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; + } + } + + if (inst->conditional_mod) { + add_dep(last_conditional_mod, n, 0); + last_conditional_mod = n; + } + } + + /* bottom-to-top dependencies: WAR */ + memset(last_grf_write, 0, sizeof(last_grf_write)); + memset(last_mrf_write, 0, sizeof(last_mrf_write)); + last_conditional_mod = NULL; + 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; + vec4_instruction *inst = (vec4_instruction *)n->inst; + + /* write-after-read deps. */ + for (int i = 0; i < 3; i++) { + if (inst->src[i].file == GRF) { + 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)) { + 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 && + inst->src[i].file != ATTR); + 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); + } + + /* Update the things this instruction wrote, so earlier reads + * can mark this as WAR dependency. + */ + if (inst->dst.file == GRF) { + last_grf_write[inst->dst.reg] = n; + } else if (inst->dst.file == MRF) { + last_mrf_write[inst->dst.reg] = n; + } else if (inst->dst.file == HW_REG && + inst->dst.fixed_hw_reg.file == BRW_GENERAL_REGISTER_FILE) { + 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; + } + } + + if (inst->conditional_mod) { + last_conditional_mod = n; + } + } +} + schedule_node * fs_instruction_scheduler::choose_instruction_to_schedule() { @@ -792,6 +970,27 @@ fs_instruction_scheduler::choose_instruction_to_schedule() return chosen; } +schedule_node * +vec4_instruction_scheduler::choose_instruction_to_schedule() +{ + schedule_node *chosen = NULL; + int chosen_time = 0; + + /* Of the instructions 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; + } + } + + return chosen; +} + int fs_instruction_scheduler::issue_time(backend_instruction *inst) { @@ -801,6 +1000,13 @@ fs_instruction_scheduler::issue_time(backend_instruction *inst) return 2; } +int +vec4_instruction_scheduler::issue_time(backend_instruction *inst) +{ + /* We always execute as two vec4s in parallel. */ + return 2; +} + void instruction_scheduler::schedule_instructions(backend_instruction *next_block_header) { @@ -929,3 +1135,16 @@ fs_visitor::schedule_instructions(bool post_reg_alloc) this->live_intervals_valid = false; } + +void +vec4_visitor::opt_schedule_instructions() +{ + vec4_instruction_scheduler sched(this, prog_data->total_grf); + sched.run(&instructions); + + if (unlikely(debug_flag)) { + printf("vec4 estimated execution time: %d cycles\n", sched.time); + } + + this->live_intervals_valid = false; +} diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp index a3ae4a155a1..c6ca4535003 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp @@ -259,6 +259,13 @@ vec4_visitor::implied_mrf_writes(vec4_instruction *inst) return 3; case SHADER_OPCODE_SHADER_TIME_ADD: return 0; + case SHADER_OPCODE_TEX: + case SHADER_OPCODE_TXL: + case SHADER_OPCODE_TXD: + case SHADER_OPCODE_TXF: + case SHADER_OPCODE_TXF_MS: + case SHADER_OPCODE_TXS: + return inst->header_present ? 1 : 0; default: assert(!"not reached"); return inst->mlen; @@ -1462,6 +1469,8 @@ vec4_visitor::run() break; } + opt_schedule_instructions(); + opt_set_dependency_control(); /* If any state parameters were appended, then ParameterValues could have diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h index 66fae69b104..06b0f6a33e1 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4.h +++ b/src/mesa/drivers/dri/i965/brw_vec4.h @@ -327,6 +327,7 @@ public: bool opt_algebraic(); bool opt_register_coalesce(); void opt_set_dependency_control(); + void opt_schedule_instructions(); bool can_do_source_mods(vec4_instruction *inst);