scoreboard_check_stage.cc revision 11308:7d8836fd043d 
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}
174