1/*
2 * Copyright (c) 2014-2015 Advanced Micro Devices, Inc.
3 * All rights reserved.
4 *
5 * For use for simulation and test purposes only
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions are met:
9 *
10 * 1. Redistributions of source code must retain the above copyright notice,
11 * this list of conditions and the following disclaimer.
12 *
13 * 2. Redistributions in binary form must reproduce the above copyright notice,
14 * this list of conditions and the following disclaimer in the documentation
15 * and/or other materials provided with the distribution.
16 *
17 * 3. Neither the name of the copyright holder nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
22 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
25 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 * POSSIBILITY OF SUCH DAMAGE.
32 *
33 * Author: Sooraj Puthoor
34 */
35
36#include "gpu-compute/scoreboard_check_stage.hh"
37
38#include "gpu-compute/compute_unit.hh"
39#include "gpu-compute/gpu_static_inst.hh"
40#include "gpu-compute/shader.hh"
41#include "gpu-compute/wavefront.hh"
42#include "params/ComputeUnit.hh"
43
44ScoreboardCheckStage::ScoreboardCheckStage(const ComputeUnitParams *p)
45 : numSIMDs(p->num_SIMDs),
46 numMemUnits(p->num_global_mem_pipes + p->num_shared_mem_pipes),
47 numGlbMemPipes(p->num_global_mem_pipes),
48 numShrMemPipes(p->num_shared_mem_pipes),
49 vectorAluInstAvail(nullptr),
50 lastGlbMemSimd(-1),
51 lastShrMemSimd(-1), glbMemInstAvail(nullptr),
52 shrMemInstAvail(nullptr)
53{
54}
55
56ScoreboardCheckStage::~ScoreboardCheckStage()
57{
58 readyList.clear();
59 waveStatusList.clear();
60 shrMemInstAvail = nullptr;
61 glbMemInstAvail = nullptr;
62}
63
64void
65ScoreboardCheckStage::init(ComputeUnit *cu)
66{
67 computeUnit = cu;
68 _name = computeUnit->name() + ".ScoreboardCheckStage";
69
70 for (int unitId = 0; unitId < numSIMDs + numMemUnits; ++unitId) {
71 readyList.push_back(&computeUnit->readyList[unitId]);
72 }
73
74 for (int unitId = 0; unitId < numSIMDs; ++unitId) {
75 waveStatusList.push_back(&computeUnit->waveStatusList[unitId]);
76 }
77
78 vectorAluInstAvail = &computeUnit->vectorAluInstAvail;
79 glbMemInstAvail= &computeUnit->glbMemInstAvail;
80 shrMemInstAvail= &computeUnit->shrMemInstAvail;
81}
82
83void
84ScoreboardCheckStage::initStatistics()
85{
86 lastGlbMemSimd = -1;
87 lastShrMemSimd = -1;
88 *glbMemInstAvail = 0;
89 *shrMemInstAvail = 0;
90
91 for (int unitId = 0; unitId < numSIMDs; ++unitId)
92 vectorAluInstAvail->at(unitId) = false;
93}
94
95void
96ScoreboardCheckStage::collectStatistics(Wavefront *curWave, int unitId)
97{
98 if (curWave->instructionBuffer.empty())
99 return;
100
101 // track which vector SIMD unit has at least one WV with a vector
102 // ALU as the oldest instruction in its Instruction buffer
103 vectorAluInstAvail->at(unitId) = vectorAluInstAvail->at(unitId) ||
104 curWave->isOldestInstALU();
105
106 // track how many vector SIMD units have at least one WV with a
107 // vector Global memory instruction as the oldest instruction
108 // in its Instruction buffer
109 if ((curWave->isOldestInstGMem() || curWave->isOldestInstPrivMem() ||
110 curWave->isOldestInstFlatMem()) && lastGlbMemSimd != unitId &&
111 *glbMemInstAvail <= 1) {
112 (*glbMemInstAvail)++;
113 lastGlbMemSimd = unitId;
114 }
115
116 // track how many vector SIMD units have at least one WV with a
117 // vector shared memory (LDS) instruction as the oldest instruction
118 // in its Instruction buffer
119 // TODO: parametrize the limit of the LDS units
120 if (curWave->isOldestInstLMem() && (*shrMemInstAvail <= numShrMemPipes) &&
121 lastShrMemSimd != unitId) {
122 (*shrMemInstAvail)++;
123 lastShrMemSimd = unitId;
124 }
125}
126
127void
128ScoreboardCheckStage::exec()
129{
130 initStatistics();
131
132 // reset the ready list for all execution units; it will be
133 // constructed every cycle since resource availability may change
134 for (int unitId = 0; unitId < numSIMDs + numMemUnits; ++unitId) {
135 readyList[unitId]->clear();
136 }
137
138 // iterate over the Wavefronts of all SIMD units
139 for (int unitId = 0; unitId < numSIMDs; ++unitId) {
140 for (int wvId = 0; wvId < computeUnit->shader->n_wf; ++wvId) {
141 // reset the ready status of each wavefront
142 waveStatusList[unitId]->at(wvId).second = BLOCKED;
143 Wavefront *curWave = waveStatusList[unitId]->at(wvId).first;
144 collectStatistics(curWave, unitId);
145
146 if (curWave->ready(Wavefront::I_ALU)) {
147 readyList[unitId]->push_back(curWave);
148 waveStatusList[unitId]->at(wvId).second = READY;
149 } else if (curWave->ready(Wavefront::I_GLOBAL)) {
150 if (computeUnit->cedeSIMD(unitId, wvId)) {
151 continue;
152 }
153
154 readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
155 waveStatusList[unitId]->at(wvId).second = READY;
156 } else if (curWave->ready(Wavefront::I_SHARED)) {
157 readyList[computeUnit->ShrMemUnitId()]->push_back(curWave);
158 waveStatusList[unitId]->at(wvId).second = READY;
159 } else if (curWave->ready(Wavefront::I_FLAT)) {
160 readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
161 waveStatusList[unitId]->at(wvId).second = READY;
162 } else if (curWave->ready(Wavefront::I_PRIVATE)) {
163 readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
164 waveStatusList[unitId]->at(wvId).second = READY;
165 }
166 }
167 }
168}
169
170void
171ScoreboardCheckStage::regStats()
172{
173}