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/*
* Copyright (c) 2014-2015 Advanced Micro Devices, Inc.
* All rights reserved.
*
* For use for simulation and test purposes only
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived from this
* software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
* Authors: John Kalamatianos,
* Sooraj Puthoor,
* Mark Wyse
*/
#include "gpu-compute/scoreboard_check_stage.hh"
#include "gpu-compute/compute_unit.hh"
#include "gpu-compute/gpu_static_inst.hh"
#include "gpu-compute/shader.hh"
#include "gpu-compute/wavefront.hh"
#include "params/ComputeUnit.hh"
ScoreboardCheckStage::ScoreboardCheckStage(const ComputeUnitParams *p)
: numSIMDs(p->num_SIMDs),
numMemUnits(p->num_global_mem_pipes + p->num_shared_mem_pipes),
numShrMemPipes(p->num_shared_mem_pipes),
vectorAluInstAvail(nullptr),
lastGlbMemSimd(-1),
lastShrMemSimd(-1), glbMemInstAvail(nullptr),
shrMemInstAvail(nullptr)
{
}
ScoreboardCheckStage::~ScoreboardCheckStage()
{
readyList.clear();
waveStatusList.clear();
shrMemInstAvail = nullptr;
glbMemInstAvail = nullptr;
}
void
ScoreboardCheckStage::init(ComputeUnit *cu)
{
computeUnit = cu;
_name = computeUnit->name() + ".ScoreboardCheckStage";
for (int unitId = 0; unitId < numSIMDs + numMemUnits; ++unitId) {
readyList.push_back(&computeUnit->readyList[unitId]);
}
for (int unitId = 0; unitId < numSIMDs; ++unitId) {
waveStatusList.push_back(&computeUnit->waveStatusList[unitId]);
}
vectorAluInstAvail = &computeUnit->vectorAluInstAvail;
glbMemInstAvail= &computeUnit->glbMemInstAvail;
shrMemInstAvail= &computeUnit->shrMemInstAvail;
}
void
ScoreboardCheckStage::initStatistics()
{
lastGlbMemSimd = -1;
lastShrMemSimd = -1;
*glbMemInstAvail = 0;
*shrMemInstAvail = 0;
for (int unitId = 0; unitId < numSIMDs; ++unitId)
vectorAluInstAvail->at(unitId) = false;
}
void
ScoreboardCheckStage::collectStatistics(Wavefront *curWave, int unitId)
{
if (curWave->instructionBuffer.empty())
return;
// track which vector SIMD unit has at least one WV with a vector
// ALU as the oldest instruction in its Instruction buffer
vectorAluInstAvail->at(unitId) = vectorAluInstAvail->at(unitId) ||
curWave->isOldestInstALU();
// track how many vector SIMD units have at least one WV with a
// vector Global memory instruction as the oldest instruction
// in its Instruction buffer
if ((curWave->isOldestInstGMem() || curWave->isOldestInstPrivMem() ||
curWave->isOldestInstFlatMem()) && lastGlbMemSimd != unitId &&
*glbMemInstAvail <= 1) {
(*glbMemInstAvail)++;
lastGlbMemSimd = unitId;
}
// track how many vector SIMD units have at least one WV with a
// vector shared memory (LDS) instruction as the oldest instruction
// in its Instruction buffer
// TODO: parametrize the limit of the LDS units
if (curWave->isOldestInstLMem() && (*shrMemInstAvail <= numShrMemPipes) &&
lastShrMemSimd != unitId) {
(*shrMemInstAvail)++;
lastShrMemSimd = unitId;
}
}
void
ScoreboardCheckStage::exec()
{
initStatistics();
// reset the ready list for all execution units; it will be
// constructed every cycle since resource availability may change
for (int unitId = 0; unitId < numSIMDs + numMemUnits; ++unitId) {
readyList[unitId]->clear();
}
// iterate over the Wavefronts of all SIMD units
for (int unitId = 0; unitId < numSIMDs; ++unitId) {
for (int wvId = 0; wvId < computeUnit->shader->n_wf; ++wvId) {
// reset the ready status of each wavefront
waveStatusList[unitId]->at(wvId).second = BLOCKED;
Wavefront *curWave = waveStatusList[unitId]->at(wvId).first;
collectStatistics(curWave, unitId);
if (curWave->ready(Wavefront::I_ALU)) {
readyList[unitId]->push_back(curWave);
waveStatusList[unitId]->at(wvId).second = READY;
} else if (curWave->ready(Wavefront::I_GLOBAL)) {
if (computeUnit->cedeSIMD(unitId, wvId)) {
continue;
}
readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
waveStatusList[unitId]->at(wvId).second = READY;
} else if (curWave->ready(Wavefront::I_SHARED)) {
readyList[computeUnit->ShrMemUnitId()]->push_back(curWave);
waveStatusList[unitId]->at(wvId).second = READY;
} else if (curWave->ready(Wavefront::I_FLAT)) {
readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
waveStatusList[unitId]->at(wvId).second = READY;
} else if (curWave->ready(Wavefront::I_PRIVATE)) {
readyList[computeUnit->GlbMemUnitId()]->push_back(curWave);
waveStatusList[unitId]->at(wvId).second = READY;
}
}
}
}
void
ScoreboardCheckStage::regStats()
{
}