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gem5/src/gpu-compute/compute_unit.cc
Tony Gutierrez 1a7d3f9fcb gpu-compute: AMD's baseline GPU model
2016-01-19 14:28:22 -05:00

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/*
* Copyright (c) 2011-2015 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.
*
* Author: John Kalamatianos, Anthony Gutierrez
*/
#include "gpu-compute/compute_unit.hh"
#include "base/output.hh"
#include "debug/GPUDisp.hh"
#include "debug/GPUExec.hh"
#include "debug/GPUFetch.hh"
#include "debug/GPUMem.hh"
#include "debug/GPUPort.hh"
#include "debug/GPUPrefetch.hh"
#include "debug/GPUSync.hh"
#include "debug/GPUTLB.hh"
#include "gpu-compute/dispatcher.hh"
#include "gpu-compute/gpu_dyn_inst.hh"
#include "gpu-compute/gpu_static_inst.hh"
#include "gpu-compute/ndrange.hh"
#include "gpu-compute/shader.hh"
#include "gpu-compute/simple_pool_manager.hh"
#include "gpu-compute/vector_register_file.hh"
#include "gpu-compute/wavefront.hh"
#include "mem/page_table.hh"
#include "sim/process.hh"
ComputeUnit::ComputeUnit(const Params *p) : MemObject(p), fetchStage(p),
scoreboardCheckStage(p), scheduleStage(p), execStage(p),
globalMemoryPipe(p), localMemoryPipe(p), rrNextMemID(0), rrNextALUWp(0),
cu_id(p->cu_id), vrf(p->vector_register_file), numSIMDs(p->num_SIMDs),
spBypassPipeLength(p->spbypass_pipe_length),
dpBypassPipeLength(p->dpbypass_pipe_length),
issuePeriod(p->issue_period),
numGlbMemUnits(p->num_global_mem_pipes),
numLocMemUnits(p->num_shared_mem_pipes),
perLaneTLB(p->perLaneTLB), prefetchDepth(p->prefetch_depth),
prefetchStride(p->prefetch_stride), prefetchType(p->prefetch_prev_type),
xact_cas_mode(p->xactCasMode), debugSegFault(p->debugSegFault),
functionalTLB(p->functionalTLB), localMemBarrier(p->localMemBarrier),
countPages(p->countPages), barrier_id(0),
vrfToCoalescerBusWidth(p->vrf_to_coalescer_bus_width),
coalescerToVrfBusWidth(p->coalescer_to_vrf_bus_width),
req_tick_latency(p->mem_req_latency * p->clk_domain->clockPeriod()),
resp_tick_latency(p->mem_resp_latency * p->clk_domain->clockPeriod()),
_masterId(p->system->getMasterId(name() + ".ComputeUnit")),
lds(*p->localDataStore), globalSeqNum(0), wavefrontSize(p->wfSize)
{
// this check will be eliminated once we have wavefront size support added
fatal_if(p->wfSize != VSZ, "Wavefront size parameter does not match VSZ");
// calculate how many cycles a vector load or store will need to transfer
// its data over the corresponding buses
numCyclesPerStoreTransfer = (uint32_t)ceil((double)(VSZ * sizeof(uint32_t))
/ (double)vrfToCoalescerBusWidth);
numCyclesPerLoadTransfer = (VSZ * sizeof(uint32_t))
/ coalescerToVrfBusWidth;
lastVaddrWF.resize(numSIMDs);
wfList.resize(numSIMDs);
for (int j = 0; j < numSIMDs; ++j) {
lastVaddrWF[j].resize(p->n_wf);
for (int i = 0; i < p->n_wf; ++i) {
lastVaddrWF[j][i].resize(VSZ);
wfList[j].push_back(p->wavefronts[j * p->n_wf + i]);
wfList[j][i]->setParent(this);
for (int k = 0; k < VSZ; ++k) {
lastVaddrWF[j][i][k] = 0;
}
}
}
lastVaddrPhase.resize(numSIMDs);
for (int i = 0; i < numSIMDs; ++i) {
lastVaddrPhase[i] = LastVaddrWave();
}
lastVaddrCU = LastVaddrWave();
lds.setParent(this);
if (p->execPolicy == "OLDEST-FIRST") {
exec_policy = EXEC_POLICY::OLDEST;
} else if (p->execPolicy == "ROUND-ROBIN") {
exec_policy = EXEC_POLICY::RR;
} else {
fatal("Invalid WF execution policy (CU)\n");
}
memPort.resize(VSZ);
// resize the tlbPort vectorArray
int tlbPort_width = perLaneTLB ? VSZ : 1;
tlbPort.resize(tlbPort_width);
cuExitCallback = new CUExitCallback(this);
registerExitCallback(cuExitCallback);
xactCasLoadMap.clear();
lastExecCycle.resize(numSIMDs, 0);
for (int i = 0; i < vrf.size(); ++i) {
vrf[i]->setParent(this);
}
numVecRegsPerSimd = vrf[0]->numRegs();
}
ComputeUnit::~ComputeUnit()
{
// Delete wavefront slots
for (int j = 0; j < numSIMDs; ++j)
for (int i = 0; i < shader->n_wf; ++i) {
delete wfList[j][i];
}
readyList.clear();
waveStatusList.clear();
dispatchList.clear();
vectorAluInstAvail.clear();
delete cuExitCallback;
delete ldsPort;
}
void
ComputeUnit::FillKernelState(Wavefront *w, NDRange *ndr)
{
w->resizeRegFiles(ndr->q.cRegCount, ndr->q.sRegCount, ndr->q.dRegCount);
w->workgroupsz[0] = ndr->q.wgSize[0];
w->workgroupsz[1] = ndr->q.wgSize[1];
w->workgroupsz[2] = ndr->q.wgSize[2];
w->wg_sz = w->workgroupsz[0] * w->workgroupsz[1] * w->workgroupsz[2];
w->gridsz[0] = ndr->q.gdSize[0];
w->gridsz[1] = ndr->q.gdSize[1];
w->gridsz[2] = ndr->q.gdSize[2];
w->kernelArgs = ndr->q.args;
w->privSizePerItem = ndr->q.privMemPerItem;
w->spillSizePerItem = ndr->q.spillMemPerItem;
w->roBase = ndr->q.roMemStart;
w->roSize = ndr->q.roMemTotal;
}
void
ComputeUnit::InitializeWFContext(WFContext *wfCtx, NDRange *ndr, int cnt,
int trueWgSize[], int trueWgSizeTotal,
LdsChunk *ldsChunk, uint64_t origSpillMemStart)
{
wfCtx->cnt = cnt;
VectorMask init_mask;
init_mask.reset();
for (int k = 0; k < VSZ; ++k) {
if (k + cnt * VSZ < trueWgSizeTotal)
init_mask[k] = 1;
}
wfCtx->init_mask = init_mask.to_ullong();
wfCtx->exec_mask = init_mask.to_ullong();
for (int i = 0; i < VSZ; ++i) {
wfCtx->bar_cnt[i] = 0;
}
wfCtx->max_bar_cnt = 0;
wfCtx->old_barrier_cnt = 0;
wfCtx->barrier_cnt = 0;
wfCtx->privBase = ndr->q.privMemStart;
ndr->q.privMemStart += ndr->q.privMemPerItem * VSZ;
wfCtx->spillBase = ndr->q.spillMemStart;
ndr->q.spillMemStart += ndr->q.spillMemPerItem * VSZ;
wfCtx->pc = 0;
wfCtx->rpc = UINT32_MAX;
// set the wavefront context to have a pointer to this section of the LDS
wfCtx->ldsChunk = ldsChunk;
// WG state
wfCtx->wg_id = ndr->globalWgId;
wfCtx->barrier_id = barrier_id;
// Kernel wide state
wfCtx->ndr = ndr;
}
void
ComputeUnit::updateEvents() {
if (!timestampVec.empty()) {
uint32_t vecSize = timestampVec.size();
uint32_t i = 0;
while (i < vecSize) {
if (timestampVec[i] <= shader->tick_cnt) {
std::pair<uint32_t, uint32_t> regInfo = regIdxVec[i];
vrf[regInfo.first]->markReg(regInfo.second, sizeof(uint32_t),
statusVec[i]);
timestampVec.erase(timestampVec.begin() + i);
regIdxVec.erase(regIdxVec.begin() + i);
statusVec.erase(statusVec.begin() + i);
--vecSize;
--i;
}
++i;
}
}
for (int i = 0; i< numSIMDs; ++i) {
vrf[i]->updateEvents();
}
}
void
ComputeUnit::StartWF(Wavefront *w, WFContext *wfCtx, int trueWgSize[],
int trueWgSizeTotal)
{
static int _n_wave = 0;
int cnt = wfCtx->cnt;
NDRange *ndr = wfCtx->ndr;
// Fill in Kernel state
FillKernelState(w, ndr);
w->kern_id = ndr->dispatchId;
w->dynwaveid = cnt;
w->init_mask = wfCtx->init_mask;
for (int k = 0; k < VSZ; ++k) {
w->workitemid[0][k] = (k+cnt*VSZ) % trueWgSize[0];
w->workitemid[1][k] = ((k + cnt * VSZ) / trueWgSize[0]) % trueWgSize[1];
w->workitemid[2][k] = (k + cnt * VSZ) / (trueWgSize[0] * trueWgSize[1]);
w->workitemFlatId[k] = w->workitemid[2][k] * trueWgSize[0] *
trueWgSize[1] + w->workitemid[1][k] * trueWgSize[0] +
w->workitemid[0][k];
}
w->old_barrier_cnt = wfCtx->old_barrier_cnt;
w->barrier_cnt = wfCtx->barrier_cnt;
w->barrier_slots = divCeil(trueWgSizeTotal, VSZ);
for (int i = 0; i < VSZ; ++i) {
w->bar_cnt[i] = wfCtx->bar_cnt[i];
}
w->max_bar_cnt = wfCtx->max_bar_cnt;
w->privBase = wfCtx->privBase;
w->spillBase = wfCtx->spillBase;
w->pushToReconvergenceStack(wfCtx->pc, wfCtx->rpc, wfCtx->exec_mask);
// WG state
w->wg_id = wfCtx->wg_id;
w->dispatchid = wfCtx->ndr->dispatchId;
w->workgroupid[0] = w->wg_id % ndr->numWg[0];
w->workgroupid[1] = (w->wg_id / ndr->numWg[0]) % ndr->numWg[1];
w->workgroupid[2] = w->wg_id / (ndr->numWg[0] * ndr->numWg[1]);
w->barrier_id = wfCtx->barrier_id;
w->stalledAtBarrier = false;
// move this from the context into the actual wavefront
w->ldsChunk = wfCtx->ldsChunk;
int32_t refCount M5_VAR_USED =
lds.increaseRefCounter(w->dispatchid, w->wg_id);
DPRINTF(GPUDisp, "CU%d: increase ref ctr wg[%d] to [%d]\n",
cu_id, w->wg_id, refCount);
w->instructionBuffer.clear();
if (w->pendingFetch)
w->dropFetch = true;
// is this the last wavefront in the workgroup
// if set the spillWidth to be the remaining work-items
// so that the vector access is correct
if ((cnt + 1) * VSZ >= trueWgSizeTotal) {
w->spillWidth = trueWgSizeTotal - (cnt * VSZ);
} else {
w->spillWidth = VSZ;
}
DPRINTF(GPUDisp, "Scheduling wfDynId/barrier_id %d/%d on CU%d: "
"WF[%d][%d]\n", _n_wave, barrier_id, cu_id, w->simdId, w->wfSlotId);
w->start(++_n_wave, ndr->q.code_ptr);
}
void
ComputeUnit::StartWorkgroup(NDRange *ndr)
{
// reserve the LDS capacity allocated to the work group
// disambiguated by the dispatch ID and workgroup ID, which should be
// globally unique
LdsChunk *ldsChunk = lds.reserveSpace(ndr->dispatchId, ndr->globalWgId,
ndr->q.ldsSize);
// Send L1 cache acquire
// isKernel + isAcquire = Kernel Begin
if (shader->impl_kern_boundary_sync) {
GPUDynInstPtr gpuDynInst = std::make_shared<GPUDynInst>(nullptr,
nullptr,
nullptr, 0);
gpuDynInst->useContinuation = false;
gpuDynInst->memoryOrder = Enums::MEMORY_ORDER_SC_ACQUIRE;
gpuDynInst->scope = Enums::MEMORY_SCOPE_SYSTEM;
injectGlobalMemFence(gpuDynInst, true);
}
// Get true size of workgroup (after clamping to grid size)
int trueWgSize[3];
int trueWgSizeTotal = 1;
for (int d = 0; d < 3; ++d) {
trueWgSize[d] = std::min(ndr->q.wgSize[d], ndr->q.gdSize[d] -
ndr->wgId[d] * ndr->q.wgSize[d]);
trueWgSizeTotal *= trueWgSize[d];
}
uint64_t origSpillMemStart = ndr->q.spillMemStart;
// calculate the number of 32-bit vector registers required by wavefront
int vregDemand = ndr->q.sRegCount + (2 * ndr->q.dRegCount);
int cnt = 0;
// Assign WFs by spreading them across SIMDs, 1 WF per SIMD at a time
for (int m = 0; m < shader->n_wf * numSIMDs; ++m) {
Wavefront *w = wfList[m % numSIMDs][m / numSIMDs];
// Check if this wavefront slot is available:
// It must be stopped and not waiting
// for a release to complete S_RETURNING
if (w->status == Wavefront::S_STOPPED) {
// if we have scheduled all work items then stop
// scheduling wavefronts
if (cnt * VSZ >= trueWgSizeTotal)
break;
// reserve vector registers for the scheduled wavefront
assert(vectorRegsReserved[m % numSIMDs] <= numVecRegsPerSimd);
uint32_t normSize = 0;
w->startVgprIndex = vrf[m % numSIMDs]->manager->
allocateRegion(vregDemand, &normSize);
w->reservedVectorRegs = normSize;
vectorRegsReserved[m % numSIMDs] += w->reservedVectorRegs;
WFContext wfCtx;
InitializeWFContext(&wfCtx, ndr, cnt, trueWgSize, trueWgSizeTotal,
ldsChunk, origSpillMemStart);
StartWF(w, &wfCtx, trueWgSize, trueWgSizeTotal);
++cnt;
}
}
++barrier_id;
}
int
ComputeUnit::ReadyWorkgroup(NDRange *ndr)
{
// Get true size of workgroup (after clamping to grid size)
int trueWgSize[3];
int trueWgSizeTotal = 1;
for (int d = 0; d < 3; ++d) {
trueWgSize[d] = std::min(ndr->q.wgSize[d], ndr->q.gdSize[d] -
ndr->wgId[d] * ndr->q.wgSize[d]);
trueWgSizeTotal *= trueWgSize[d];
DPRINTF(GPUDisp, "trueWgSize[%d] = %d\n", d, trueWgSize[d]);
}
DPRINTF(GPUDisp, "trueWgSizeTotal = %d\n", trueWgSizeTotal);
// calculate the number of 32-bit vector registers required by each
// work item of the work group
int vregDemandPerWI = ndr->q.sRegCount + (2 * ndr->q.dRegCount);
bool vregAvail = true;
int numWfs = (trueWgSizeTotal + VSZ - 1) / VSZ;
int freeWfSlots = 0;
// check if the total number of VGPRs required by all WFs of the WG
// fit in the VRFs of all SIMD units
assert((numWfs * vregDemandPerWI) <= (numSIMDs * numVecRegsPerSimd));
int numMappedWfs = 0;
std::vector<int> numWfsPerSimd;
numWfsPerSimd.resize(numSIMDs, 0);
// find how many free WF slots we have across all SIMDs
for (int j = 0; j < shader->n_wf; ++j) {
for (int i = 0; i < numSIMDs; ++i) {
if (wfList[i][j]->status == Wavefront::S_STOPPED) {
// count the number of free WF slots
++freeWfSlots;
if (numMappedWfs < numWfs) {
// count the WFs to be assigned per SIMD
numWfsPerSimd[i]++;
}
numMappedWfs++;
}
}
}
// if there are enough free WF slots then find if there are enough
// free VGPRs per SIMD based on the WF->SIMD mapping
if (freeWfSlots >= numWfs) {
for (int j = 0; j < numSIMDs; ++j) {
// find if there are enough free VGPR regions in the SIMD's VRF
// to accommodate the WFs of the new WG that would be mapped to
// this SIMD unit
vregAvail = vrf[j]->manager->canAllocate(numWfsPerSimd[j],
vregDemandPerWI);
// stop searching if there is at least one SIMD
// whose VRF does not have enough free VGPR pools.
// This is because a WG is scheduled only if ALL
// of its WFs can be scheduled
if (!vregAvail)
break;
}
}
DPRINTF(GPUDisp, "Free WF slots = %d, VGPR Availability = %d\n",
freeWfSlots, vregAvail);
if (!vregAvail) {
++numTimesWgBlockedDueVgprAlloc;
}
// Return true if enough WF slots to submit workgroup and if there are
// enough VGPRs to schedule all WFs to their SIMD units
if (!lds.canReserve(ndr->q.ldsSize)) {
wgBlockedDueLdsAllocation++;
}
// Return true if (a) there are enough free WF slots to submit
// workgrounp and (b) if there are enough VGPRs to schedule all WFs to their
// SIMD units and (c) if there is enough space in LDS
return freeWfSlots >= numWfs && vregAvail && lds.canReserve(ndr->q.ldsSize);
}
int
ComputeUnit::AllAtBarrier(uint32_t _barrier_id, uint32_t bcnt, uint32_t bslots)
{
DPRINTF(GPUSync, "CU%d: Checking for All At Barrier\n", cu_id);
int ccnt = 0;
for (int i_simd = 0; i_simd < numSIMDs; ++i_simd) {
for (int i_wf = 0; i_wf < shader->n_wf; ++i_wf) {
Wavefront *w = wfList[i_simd][i_wf];
if (w->status == Wavefront::S_RUNNING) {
DPRINTF(GPUSync, "Checking WF[%d][%d]\n", i_simd, i_wf);
DPRINTF(GPUSync, "wf->barrier_id = %d, _barrier_id = %d\n",
w->barrier_id, _barrier_id);
DPRINTF(GPUSync, "wf->barrier_cnt %d, bcnt = %d\n",
w->barrier_cnt, bcnt);
}
if (w->status == Wavefront::S_RUNNING &&
w->barrier_id == _barrier_id && w->barrier_cnt == bcnt &&
!w->outstanding_reqs) {
++ccnt;
DPRINTF(GPUSync, "WF[%d][%d] at barrier, increment ccnt to "
"%d\n", i_simd, i_wf, ccnt);
}
}
}
DPRINTF(GPUSync, "CU%d: returning allAtBarrier ccnt = %d, bslots = %d\n",
cu_id, ccnt, bslots);
return ccnt == bslots;
}
// Check if the current wavefront is blocked on additional resources.
bool
ComputeUnit::cedeSIMD(int simdId, int wfSlotId)
{
bool cede = false;
// If --xact-cas-mode option is enabled in run.py, then xact_cas_ld
// magic instructions will impact the scheduling of wavefronts
if (xact_cas_mode) {
/*
* When a wavefront calls xact_cas_ld, it adds itself to a per address
* queue. All per address queues are managed by the xactCasLoadMap.
*
* A wavefront is not blocked if: it is not in ANY per address queue or
* if it is at the head of a per address queue.
*/
for (auto itMap : xactCasLoadMap) {
std::list<waveIdentifier> curWaveIDQueue = itMap.second.waveIDQueue;
if (!curWaveIDQueue.empty()) {
for (auto it : curWaveIDQueue) {
waveIdentifier cur_wave = it;
if (cur_wave.simdId == simdId &&
cur_wave.wfSlotId == wfSlotId) {
// 2 possibilities
// 1: this WF has a green light
// 2: another WF has a green light
waveIdentifier owner_wave = curWaveIDQueue.front();
if (owner_wave.simdId != cur_wave.simdId ||
owner_wave.wfSlotId != cur_wave.wfSlotId) {
// possibility 2
cede = true;
break;
} else {
// possibility 1
break;
}
}
}
}
}
}
return cede;
}
// Execute one clock worth of work on the ComputeUnit.
void
ComputeUnit::exec()
{
updateEvents();
// Execute pipeline stages in reverse order to simulate
// the pipeline latency
globalMemoryPipe.exec();
localMemoryPipe.exec();
execStage.exec();
scheduleStage.exec();
scoreboardCheckStage.exec();
fetchStage.exec();
totalCycles++;
}
void
ComputeUnit::init()
{
// Initialize CU Bus models
glbMemToVrfBus.init(&shader->tick_cnt, 1);
locMemToVrfBus.init(&shader->tick_cnt, 1);
nextGlbMemBus = 0;
nextLocMemBus = 0;
fatal_if(numGlbMemUnits > 1,
"No support for multiple Global Memory Pipelines exists!!!");
vrfToGlobalMemPipeBus.resize(numGlbMemUnits);
for (int j = 0; j < numGlbMemUnits; ++j) {
vrfToGlobalMemPipeBus[j] = WaitClass();
vrfToGlobalMemPipeBus[j].init(&shader->tick_cnt, 1);
}
fatal_if(numLocMemUnits > 1,
"No support for multiple Local Memory Pipelines exists!!!");
vrfToLocalMemPipeBus.resize(numLocMemUnits);
for (int j = 0; j < numLocMemUnits; ++j) {
vrfToLocalMemPipeBus[j] = WaitClass();
vrfToLocalMemPipeBus[j].init(&shader->tick_cnt, 1);
}
vectorRegsReserved.resize(numSIMDs, 0);
aluPipe.resize(numSIMDs);
wfWait.resize(numSIMDs + numLocMemUnits + numGlbMemUnits);
for (int i = 0; i < numSIMDs + numLocMemUnits + numGlbMemUnits; ++i) {
wfWait[i] = WaitClass();
wfWait[i].init(&shader->tick_cnt, 1);
}
for (int i = 0; i < numSIMDs; ++i) {
aluPipe[i] = WaitClass();
aluPipe[i].init(&shader->tick_cnt, 1);
}
// Setup space for call args
for (int j = 0; j < numSIMDs; ++j) {
for (int i = 0; i < shader->n_wf; ++i) {
wfList[j][i]->initCallArgMem(shader->funcargs_size);
}
}
// Initializing pipeline resources
readyList.resize(numSIMDs + numGlbMemUnits + numLocMemUnits);
waveStatusList.resize(numSIMDs);
for (int j = 0; j < numSIMDs; ++j) {
for (int i = 0; i < shader->n_wf; ++i) {
waveStatusList[j].push_back(
std::make_pair(wfList[j][i], BLOCKED));
}
}
for (int j = 0; j < (numSIMDs + numGlbMemUnits + numLocMemUnits); ++j) {
dispatchList.push_back(std::make_pair((Wavefront*)nullptr, EMPTY));
}
fetchStage.init(this);
scoreboardCheckStage.init(this);
scheduleStage.init(this);
execStage.init(this);
globalMemoryPipe.init(this);
localMemoryPipe.init(this);
// initialize state for statistics calculation
vectorAluInstAvail.resize(numSIMDs, false);
shrMemInstAvail = 0;
glbMemInstAvail = 0;
}
bool
ComputeUnit::DataPort::recvTimingResp(PacketPtr pkt)
{
// Ruby has completed the memory op. Schedule the mem_resp_event at the
// appropriate cycle to process the timing memory response
// This delay represents the pipeline delay
SenderState *sender_state = safe_cast<SenderState*>(pkt->senderState);
int index = sender_state->port_index;
GPUDynInstPtr gpuDynInst = sender_state->_gpuDynInst;
// Is the packet returned a Kernel End or Barrier
if (pkt->req->isKernel() && pkt->req->isRelease()) {
Wavefront *w =
computeUnit->wfList[gpuDynInst->simdId][gpuDynInst->wfSlotId];
// Check if we are waiting on Kernel End Release
if (w->status == Wavefront::S_RETURNING) {
DPRINTF(GPUDisp, "CU%d: WF[%d][%d][wv=%d]: WG id completed %d\n",
computeUnit->cu_id, w->simdId, w->wfSlotId,
w->wfDynId, w->kern_id);
computeUnit->shader->dispatcher->notifyWgCompl(w);
w->status = Wavefront::S_STOPPED;
} else {
w->outstanding_reqs--;
}
DPRINTF(GPUSync, "CU%d: WF[%d][%d]: barrier_cnt = %d\n",
computeUnit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, w->barrier_cnt);
if (gpuDynInst->useContinuation) {
assert(gpuDynInst->scope != Enums::MEMORY_SCOPE_NONE);
gpuDynInst->execContinuation(gpuDynInst->staticInstruction(),
gpuDynInst);
}
delete pkt->senderState;
delete pkt->req;
delete pkt;
return true;
} else if (pkt->req->isKernel() && pkt->req->isAcquire()) {
if (gpuDynInst->useContinuation) {
assert(gpuDynInst->scope != Enums::MEMORY_SCOPE_NONE);
gpuDynInst->execContinuation(gpuDynInst->staticInstruction(),
gpuDynInst);
}
delete pkt->senderState;
delete pkt->req;
delete pkt;
return true;
}
ComputeUnit::DataPort::MemRespEvent *mem_resp_event =
new ComputeUnit::DataPort::MemRespEvent(computeUnit->memPort[index],
pkt);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: index %d, addr %#x received!\n",
computeUnit->cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
index, pkt->req->getPaddr());
computeUnit->schedule(mem_resp_event,
curTick() + computeUnit->resp_tick_latency);
return true;
}
void
ComputeUnit::DataPort::recvReqRetry()
{
int len = retries.size();
assert(len > 0);
for (int i = 0; i < len; ++i) {
PacketPtr pkt = retries.front().first;
GPUDynInstPtr gpuDynInst M5_VAR_USED = retries.front().second;
DPRINTF(GPUMem, "CU%d: WF[%d][%d]: retry mem inst addr %#x\n",
computeUnit->cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
pkt->req->getPaddr());
/** Currently Ruby can return false due to conflicts for the particular
* cache block or address. Thus other requests should be allowed to
* pass and the data port should expect multiple retries. */
if (!sendTimingReq(pkt)) {
DPRINTF(GPUMem, "failed again!\n");
break;
} else {
DPRINTF(GPUMem, "successful!\n");
retries.pop_front();
}
}
}
bool
ComputeUnit::SQCPort::recvTimingResp(PacketPtr pkt)
{
computeUnit->fetchStage.processFetchReturn(pkt);
return true;
}
void
ComputeUnit::SQCPort::recvReqRetry()
{
int len = retries.size();
assert(len > 0);
for (int i = 0; i < len; ++i) {
PacketPtr pkt = retries.front().first;
Wavefront *wavefront M5_VAR_USED = retries.front().second;
DPRINTF(GPUFetch, "CU%d: WF[%d][%d]: retrying FETCH addr %#x\n",
computeUnit->cu_id, wavefront->simdId, wavefront->wfSlotId,
pkt->req->getPaddr());
if (!sendTimingReq(pkt)) {
DPRINTF(GPUFetch, "failed again!\n");
break;
} else {
DPRINTF(GPUFetch, "successful!\n");
retries.pop_front();
}
}
}
void
ComputeUnit::sendRequest(GPUDynInstPtr gpuDynInst, int index, PacketPtr pkt)
{
// There must be a way around this check to do the globalMemStart...
Addr tmp_vaddr = pkt->req->getVaddr();
updatePageDivergenceDist(tmp_vaddr);
pkt->req->setVirt(pkt->req->getAsid(), tmp_vaddr, pkt->req->getSize(),
pkt->req->getFlags(), pkt->req->masterId(),
pkt->req->getPC());
// figure out the type of the request to set read/write
BaseTLB::Mode TLB_mode;
assert(pkt->isRead() || pkt->isWrite());
// Check write before read for atomic operations
// since atomic operations should use BaseTLB::Write
if (pkt->isWrite()){
TLB_mode = BaseTLB::Write;
} else if (pkt->isRead()) {
TLB_mode = BaseTLB::Read;
} else {
fatal("pkt is not a read nor a write\n");
}
tlbCycles -= curTick();
++tlbRequests;
int tlbPort_index = perLaneTLB ? index : 0;
if (shader->timingSim) {
if (debugSegFault) {
Process *p = shader->gpuTc->getProcessPtr();
Addr vaddr = pkt->req->getVaddr();
unsigned size = pkt->getSize();
if ((vaddr + size - 1) % 64 < vaddr % 64) {
panic("CU%d: WF[%d][%d]: Access to addr %#x is unaligned!\n",
cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId, vaddr);
}
Addr paddr;
if (!p->pTable->translate(vaddr, paddr)) {
if (!p->fixupStackFault(vaddr)) {
panic("CU%d: WF[%d][%d]: Fault on addr %#x!\n",
cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
vaddr);
}
}
}
// This is the SenderState needed upon return
pkt->senderState = new DTLBPort::SenderState(gpuDynInst, index);
// This is the senderState needed by the TLB hierarchy to function
TheISA::GpuTLB::TranslationState *translation_state =
new TheISA::GpuTLB::TranslationState(TLB_mode, shader->gpuTc, false,
pkt->senderState);
pkt->senderState = translation_state;
if (functionalTLB) {
tlbPort[tlbPort_index]->sendFunctional(pkt);
// update the hitLevel distribution
int hit_level = translation_state->hitLevel;
assert(hit_level != -1);
hitsPerTLBLevel[hit_level]++;
// New SenderState for the memory access
X86ISA::GpuTLB::TranslationState *sender_state =
safe_cast<X86ISA::GpuTLB::TranslationState*>(pkt->senderState);
delete sender_state->tlbEntry;
delete sender_state->saved;
delete sender_state;
assert(pkt->req->hasPaddr());
assert(pkt->req->hasSize());
uint8_t *tmpData = pkt->getPtr<uint8_t>();
// this is necessary because the GPU TLB receives packets instead
// of requests. when the translation is complete, all relevent
// fields in the request will be populated, but not in the packet.
// here we create the new packet so we can set the size, addr,
// and proper flags.
PacketPtr oldPkt = pkt;
pkt = new Packet(oldPkt->req, oldPkt->cmd);
delete oldPkt;
pkt->dataStatic(tmpData);
// New SenderState for the memory access
pkt->senderState = new ComputeUnit::DataPort::SenderState(gpuDynInst,
index, nullptr);
gpuDynInst->memStatusVector[pkt->getAddr()].push_back(index);
gpuDynInst->tlbHitLevel[index] = hit_level;
// translation is done. Schedule the mem_req_event at the
// appropriate cycle to send the timing memory request to ruby
ComputeUnit::DataPort::MemReqEvent *mem_req_event =
new ComputeUnit::DataPort::MemReqEvent(memPort[index], pkt);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: index %d, addr %#x data "
"scheduled\n", cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, index, pkt->req->getPaddr());
schedule(mem_req_event, curTick() + req_tick_latency);
} else if (tlbPort[tlbPort_index]->isStalled()) {
assert(tlbPort[tlbPort_index]->retries.size() > 0);
DPRINTF(GPUTLB, "CU%d: WF[%d][%d]: Translation for addr %#x "
"failed!\n", cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
tmp_vaddr);
tlbPort[tlbPort_index]->retries.push_back(pkt);
} else if (!tlbPort[tlbPort_index]->sendTimingReq(pkt)) {
// Stall the data port;
// No more packet will be issued till
// ruby indicates resources are freed by
// a recvReqRetry() call back on this port.
tlbPort[tlbPort_index]->stallPort();
DPRINTF(GPUTLB, "CU%d: WF[%d][%d]: Translation for addr %#x "
"failed!\n", cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
tmp_vaddr);
tlbPort[tlbPort_index]->retries.push_back(pkt);
} else {
DPRINTF(GPUTLB,
"CU%d: WF[%d][%d]: Translation for addr %#x sent!\n",
cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId, tmp_vaddr);
}
} else {
if (pkt->cmd == MemCmd::MemFenceReq) {
gpuDynInst->statusBitVector = VectorMask(0);
} else {
gpuDynInst->statusBitVector &= (~(1ll << index));
}
// New SenderState for the memory access
delete pkt->senderState;
// Because it's atomic operation, only need TLB translation state
pkt->senderState = new TheISA::GpuTLB::TranslationState(TLB_mode,
shader->gpuTc);
tlbPort[tlbPort_index]->sendFunctional(pkt);
// the addr of the packet is not modified, so we need to create a new
// packet, or otherwise the memory access will have the old virtual
// address sent in the translation packet, instead of the physical
// address returned by the translation.
PacketPtr new_pkt = new Packet(pkt->req, pkt->cmd);
new_pkt->dataStatic(pkt->getPtr<uint8_t>());
// Translation is done. It is safe to send the packet to memory.
memPort[0]->sendFunctional(new_pkt);
DPRINTF(GPUMem, "CU%d: WF[%d][%d]: index %d: addr %#x\n", cu_id,
gpuDynInst->simdId, gpuDynInst->wfSlotId, index,
new_pkt->req->getPaddr());
// safe_cast the senderState
TheISA::GpuTLB::TranslationState *sender_state =
safe_cast<TheISA::GpuTLB::TranslationState*>(pkt->senderState);
delete sender_state->tlbEntry;
delete new_pkt;
delete pkt->senderState;
delete pkt->req;
delete pkt;
}
}
void
ComputeUnit::sendSyncRequest(GPUDynInstPtr gpuDynInst, int index, PacketPtr pkt)
{
ComputeUnit::DataPort::MemReqEvent *mem_req_event =
new ComputeUnit::DataPort::MemReqEvent(memPort[index], pkt);
// New SenderState for the memory access
pkt->senderState = new ComputeUnit::DataPort::SenderState(gpuDynInst, index,
nullptr);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: index %d, addr %#x sync scheduled\n",
cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId, index,
pkt->req->getPaddr());
schedule(mem_req_event, curTick() + req_tick_latency);
}
void
ComputeUnit::injectGlobalMemFence(GPUDynInstPtr gpuDynInst, bool kernelLaunch,
Request* req)
{
if (!req) {
req = new Request(0, 0, 0, 0, masterId(), 0, gpuDynInst->wfDynId, -1);
}
req->setPaddr(0);
if (kernelLaunch) {
req->setFlags(Request::KERNEL);
}
gpuDynInst->s_type = SEG_GLOBAL;
// for non-kernel MemFence operations, memorder flags are set depending
// on which type of request is currently being sent, so this
// should be set by the caller (e.g. if an inst has acq-rel
// semantics, it will send one acquire req an one release req)
gpuDynInst->setRequestFlags(req, kernelLaunch);
// a mem fence must correspond to an acquire/release request
assert(req->isAcquire() || req->isRelease());
// create packet
PacketPtr pkt = new Packet(req, MemCmd::MemFenceReq);
// set packet's sender state
pkt->senderState =
new ComputeUnit::DataPort::SenderState(gpuDynInst, 0, nullptr);
// send the packet
sendSyncRequest(gpuDynInst, 0, pkt);
}
const char*
ComputeUnit::DataPort::MemRespEvent::description() const
{
return "ComputeUnit memory response event";
}
void
ComputeUnit::DataPort::MemRespEvent::process()
{
DataPort::SenderState *sender_state =
safe_cast<DataPort::SenderState*>(pkt->senderState);
GPUDynInstPtr gpuDynInst = sender_state->_gpuDynInst;
ComputeUnit *compute_unit = dataPort->computeUnit;
assert(gpuDynInst);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: Response for addr %#x, index %d\n",
compute_unit->cu_id, gpuDynInst->simdId, gpuDynInst->wfSlotId,
pkt->req->getPaddr(), dataPort->index);
Addr paddr = pkt->req->getPaddr();
if (pkt->cmd != MemCmd::MemFenceResp) {
int index = gpuDynInst->memStatusVector[paddr].back();
DPRINTF(GPUMem, "Response for addr %#x, index %d\n",
pkt->req->getPaddr(), index);
gpuDynInst->memStatusVector[paddr].pop_back();
gpuDynInst->pAddr = pkt->req->getPaddr();
if (pkt->isRead() || pkt->isWrite()) {
if (gpuDynInst->n_reg <= MAX_REGS_FOR_NON_VEC_MEM_INST) {
gpuDynInst->statusBitVector &= (~(1ULL << index));
} else {
assert(gpuDynInst->statusVector[index] > 0);
gpuDynInst->statusVector[index]--;
if (!gpuDynInst->statusVector[index])
gpuDynInst->statusBitVector &= (~(1ULL << index));
}
DPRINTF(GPUMem, "bitvector is now %#x\n",
gpuDynInst->statusBitVector);
if (gpuDynInst->statusBitVector == VectorMask(0)) {
auto iter = gpuDynInst->memStatusVector.begin();
auto end = gpuDynInst->memStatusVector.end();
while (iter != end) {
assert(iter->second.empty());
++iter;
}
gpuDynInst->memStatusVector.clear();
if (gpuDynInst->n_reg > MAX_REGS_FOR_NON_VEC_MEM_INST)
gpuDynInst->statusVector.clear();
if (gpuDynInst->m_op == Enums::MO_LD || MO_A(gpuDynInst->m_op)
|| MO_ANR(gpuDynInst->m_op)) {
assert(compute_unit->globalMemoryPipe.isGMLdRespFIFOWrRdy());
compute_unit->globalMemoryPipe.getGMLdRespFIFO()
.push(gpuDynInst);
} else {
assert(compute_unit->globalMemoryPipe.isGMStRespFIFOWrRdy());
compute_unit->globalMemoryPipe.getGMStRespFIFO()
.push(gpuDynInst);
}
DPRINTF(GPUMem, "CU%d: WF[%d][%d]: packet totally complete\n",
compute_unit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId);
// after clearing the status vectors,
// see if there is a continuation to perform
// the continuation may generate more work for
// this memory request
if (gpuDynInst->useContinuation) {
assert(gpuDynInst->scope != Enums::MEMORY_SCOPE_NONE);
gpuDynInst->execContinuation(gpuDynInst->staticInstruction(),
gpuDynInst);
}
}
}
} else {
gpuDynInst->statusBitVector = VectorMask(0);
if (gpuDynInst->useContinuation) {
assert(gpuDynInst->scope != Enums::MEMORY_SCOPE_NONE);
gpuDynInst->execContinuation(gpuDynInst->staticInstruction(),
gpuDynInst);
}
}
delete pkt->senderState;
delete pkt->req;
delete pkt;
}
ComputeUnit*
ComputeUnitParams::create()
{
return new ComputeUnit(this);
}
bool
ComputeUnit::DTLBPort::recvTimingResp(PacketPtr pkt)
{
Addr line = pkt->req->getPaddr();
DPRINTF(GPUTLB, "CU%d: DTLBPort received %#x->%#x\n", computeUnit->cu_id,
pkt->req->getVaddr(), line);
assert(pkt->senderState);
computeUnit->tlbCycles += curTick();
// pop off the TLB translation state
TheISA::GpuTLB::TranslationState *translation_state =
safe_cast<TheISA::GpuTLB::TranslationState*>(pkt->senderState);
// no PageFaults are permitted for data accesses
if (!translation_state->tlbEntry->valid) {
DTLBPort::SenderState *sender_state =
safe_cast<DTLBPort::SenderState*>(translation_state->saved);
Wavefront *w M5_VAR_USED =
computeUnit->wfList[sender_state->_gpuDynInst->simdId]
[sender_state->_gpuDynInst->wfSlotId];
DPRINTFN("Wave %d couldn't tranlate vaddr %#x\n", w->wfDynId,
pkt->req->getVaddr());
}
assert(translation_state->tlbEntry->valid);
// update the hitLevel distribution
int hit_level = translation_state->hitLevel;
computeUnit->hitsPerTLBLevel[hit_level]++;
delete translation_state->tlbEntry;
assert(!translation_state->ports.size());
pkt->senderState = translation_state->saved;
// for prefetch pkt
BaseTLB::Mode TLB_mode = translation_state->tlbMode;
delete translation_state;
// use the original sender state to know how to close this transaction
DTLBPort::SenderState *sender_state =
safe_cast<DTLBPort::SenderState*>(pkt->senderState);
GPUDynInstPtr gpuDynInst = sender_state->_gpuDynInst;
int mp_index = sender_state->portIndex;
Addr vaddr = pkt->req->getVaddr();
gpuDynInst->memStatusVector[line].push_back(mp_index);
gpuDynInst->tlbHitLevel[mp_index] = hit_level;
MemCmd requestCmd;
if (pkt->cmd == MemCmd::ReadResp) {
requestCmd = MemCmd::ReadReq;
} else if (pkt->cmd == MemCmd::WriteResp) {
requestCmd = MemCmd::WriteReq;
} else if (pkt->cmd == MemCmd::SwapResp) {
requestCmd = MemCmd::SwapReq;
} else {
panic("unsupported response to request conversion %s\n",
pkt->cmd.toString());
}
if (computeUnit->prefetchDepth) {
int simdId = gpuDynInst->simdId;
int wfSlotId = gpuDynInst->wfSlotId;
Addr last = 0;
switch(computeUnit->prefetchType) {
case Enums::PF_CU:
last = computeUnit->lastVaddrCU[mp_index];
break;
case Enums::PF_PHASE:
last = computeUnit->lastVaddrPhase[simdId][mp_index];
break;
case Enums::PF_WF:
last = computeUnit->lastVaddrWF[simdId][wfSlotId][mp_index];
default:
break;
}
DPRINTF(GPUPrefetch, "CU[%d][%d][%d][%d]: %#x was last\n",
computeUnit->cu_id, simdId, wfSlotId, mp_index, last);
int stride = last ? (roundDown(vaddr, TheISA::PageBytes) -
roundDown(last, TheISA::PageBytes)) >> TheISA::PageShift
: 0;
DPRINTF(GPUPrefetch, "Stride is %d\n", stride);
computeUnit->lastVaddrCU[mp_index] = vaddr;
computeUnit->lastVaddrPhase[simdId][mp_index] = vaddr;
computeUnit->lastVaddrWF[simdId][wfSlotId][mp_index] = vaddr;
stride = (computeUnit->prefetchType == Enums::PF_STRIDE) ?
computeUnit->prefetchStride: stride;
DPRINTF(GPUPrefetch, "%#x to: CU[%d][%d][%d][%d]\n", vaddr,
computeUnit->cu_id, simdId, wfSlotId, mp_index);
DPRINTF(GPUPrefetch, "Prefetching from %#x:", vaddr);
// Prefetch Next few pages atomically
for (int pf = 1; pf <= computeUnit->prefetchDepth; ++pf) {
DPRINTF(GPUPrefetch, "%d * %d: %#x\n", pf, stride,
vaddr+stride*pf*TheISA::PageBytes);
if (!stride)
break;
Request *prefetch_req = new Request(0, vaddr + stride * pf *
TheISA::PageBytes,
sizeof(uint8_t), 0,
computeUnit->masterId(),
0, 0, 0);
PacketPtr prefetch_pkt = new Packet(prefetch_req, requestCmd);
uint8_t foo = 0;
prefetch_pkt->dataStatic(&foo);
// Because it's atomic operation, only need TLB translation state
prefetch_pkt->senderState =
new TheISA::GpuTLB::TranslationState(TLB_mode,
computeUnit->shader->gpuTc,
true);
// Currently prefetches are zero-latency, hence the sendFunctional
sendFunctional(prefetch_pkt);
/* safe_cast the senderState */
TheISA::GpuTLB::TranslationState *tlb_state =
safe_cast<TheISA::GpuTLB::TranslationState*>(
prefetch_pkt->senderState);
delete tlb_state->tlbEntry;
delete tlb_state;
delete prefetch_pkt->req;
delete prefetch_pkt;
}
}
// First we must convert the response cmd back to a request cmd so that
// the request can be sent through the cu's master port
PacketPtr new_pkt = new Packet(pkt->req, requestCmd);
new_pkt->dataStatic(pkt->getPtr<uint8_t>());
delete pkt->senderState;
delete pkt;
// New SenderState for the memory access
new_pkt->senderState =
new ComputeUnit::DataPort::SenderState(gpuDynInst, mp_index,
nullptr);
// translation is done. Schedule the mem_req_event at the appropriate
// cycle to send the timing memory request to ruby
ComputeUnit::DataPort::MemReqEvent *mem_req_event =
new ComputeUnit::DataPort::MemReqEvent(computeUnit->memPort[mp_index],
new_pkt);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: index %d, addr %#x data scheduled\n",
computeUnit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, mp_index, new_pkt->req->getPaddr());
computeUnit->schedule(mem_req_event, curTick() +
computeUnit->req_tick_latency);
return true;
}
const char*
ComputeUnit::DataPort::MemReqEvent::description() const
{
return "ComputeUnit memory request event";
}
void
ComputeUnit::DataPort::MemReqEvent::process()
{
SenderState *sender_state = safe_cast<SenderState*>(pkt->senderState);
GPUDynInstPtr gpuDynInst = sender_state->_gpuDynInst;
ComputeUnit *compute_unit M5_VAR_USED = dataPort->computeUnit;
if (!(dataPort->sendTimingReq(pkt))) {
dataPort->retries.push_back(std::make_pair(pkt, gpuDynInst));
DPRINTF(GPUPort,
"CU%d: WF[%d][%d]: index %d, addr %#x data req failed!\n",
compute_unit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, dataPort->index,
pkt->req->getPaddr());
} else {
DPRINTF(GPUPort,
"CU%d: WF[%d][%d]: index %d, addr %#x data req sent!\n",
compute_unit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, dataPort->index,
pkt->req->getPaddr());
}
}
/*
* The initial translation request could have been rejected,
* if <retries> queue is not Retry sending the translation
* request. sendRetry() is called from the peer port whenever
* a translation completes.
*/
void
ComputeUnit::DTLBPort::recvReqRetry()
{
int len = retries.size();
DPRINTF(GPUTLB, "CU%d: DTLB recvReqRetry - %d pending requests\n",
computeUnit->cu_id, len);
assert(len > 0);
assert(isStalled());
// recvReqRetry is an indication that the resource on which this
// port was stalling on is freed. So, remove the stall first
unstallPort();
for (int i = 0; i < len; ++i) {
PacketPtr pkt = retries.front();
Addr vaddr M5_VAR_USED = pkt->req->getVaddr();
DPRINTF(GPUTLB, "CU%d: retrying D-translaton for address%#x", vaddr);
if (!sendTimingReq(pkt)) {
// Stall port
stallPort();
DPRINTF(GPUTLB, ": failed again\n");
break;
} else {
DPRINTF(GPUTLB, ": successful\n");
retries.pop_front();
}
}
}
bool
ComputeUnit::ITLBPort::recvTimingResp(PacketPtr pkt)
{
Addr line M5_VAR_USED = pkt->req->getPaddr();
DPRINTF(GPUTLB, "CU%d: ITLBPort received %#x->%#x\n",
computeUnit->cu_id, pkt->req->getVaddr(), line);
assert(pkt->senderState);
// pop off the TLB translation state
TheISA::GpuTLB::TranslationState *translation_state =
safe_cast<TheISA::GpuTLB::TranslationState*>(pkt->senderState);
bool success = translation_state->tlbEntry->valid;
delete translation_state->tlbEntry;
assert(!translation_state->ports.size());
pkt->senderState = translation_state->saved;
delete translation_state;
// use the original sender state to know how to close this transaction
ITLBPort::SenderState *sender_state =
safe_cast<ITLBPort::SenderState*>(pkt->senderState);
// get the wavefront associated with this translation request
Wavefront *wavefront = sender_state->wavefront;
delete pkt->senderState;
if (success) {
// pkt is reused in fetch(), don't delete it here. However, we must
// reset the command to be a request so that it can be sent through
// the cu's master port
assert(pkt->cmd == MemCmd::ReadResp);
pkt->cmd = MemCmd::ReadReq;
computeUnit->fetchStage.fetch(pkt, wavefront);
} else {
if (wavefront->dropFetch) {
assert(wavefront->instructionBuffer.empty());
wavefront->dropFetch = false;
}
wavefront->pendingFetch = 0;
}
return true;
}
/*
* The initial translation request could have been rejected, if
* <retries> queue is not empty. Retry sending the translation
* request. sendRetry() is called from the peer port whenever
* a translation completes.
*/
void
ComputeUnit::ITLBPort::recvReqRetry()
{
int len = retries.size();
DPRINTF(GPUTLB, "CU%d: ITLB recvReqRetry - %d pending requests\n", len);
assert(len > 0);
assert(isStalled());
// recvReqRetry is an indication that the resource on which this
// port was stalling on is freed. So, remove the stall first
unstallPort();
for (int i = 0; i < len; ++i) {
PacketPtr pkt = retries.front();
Addr vaddr M5_VAR_USED = pkt->req->getVaddr();
DPRINTF(GPUTLB, "CU%d: retrying I-translaton for address%#x", vaddr);
if (!sendTimingReq(pkt)) {
stallPort(); // Stall port
DPRINTF(GPUTLB, ": failed again\n");
break;
} else {
DPRINTF(GPUTLB, ": successful\n");
retries.pop_front();
}
}
}
void
ComputeUnit::regStats()
{
tlbCycles
.name(name() + ".tlb_cycles")
.desc("total number of cycles for all uncoalesced requests")
;
tlbRequests
.name(name() + ".tlb_requests")
.desc("number of uncoalesced requests")
;
tlbLatency
.name(name() + ".avg_translation_latency")
.desc("Avg. translation latency for data translations")
;
tlbLatency = tlbCycles / tlbRequests;
hitsPerTLBLevel
.init(4)
.name(name() + ".TLB_hits_distribution")
.desc("TLB hits distribution (0 for page table, x for Lx-TLB")
;
// fixed number of TLB levels
for (int i = 0; i < 4; ++i) {
if (!i)
hitsPerTLBLevel.subname(i,"page_table");
else
hitsPerTLBLevel.subname(i, csprintf("L%d_TLB",i));
}
execRateDist
.init(0, 10, 2)
.name(name() + ".inst_exec_rate")
.desc("Instruction Execution Rate: Number of executed vector "
"instructions per cycle")
;
ldsBankConflictDist
.init(0, VSZ, 2)
.name(name() + ".lds_bank_conflicts")
.desc("Number of bank conflicts per LDS memory packet")
;
ldsBankAccesses
.name(name() + ".lds_bank_access_cnt")
.desc("Total number of LDS bank accesses")
;
pageDivergenceDist
// A wavefront can touch 1 to VSZ pages per memory instruction.
// The number of pages per bin can be configured (here it's 4).
.init(1, VSZ, 4)
.name(name() + ".page_divergence_dist")
.desc("pages touched per wf (over all mem. instr.)")
;
controlFlowDivergenceDist
.init(1, VSZ, 4)
.name(name() + ".warp_execution_dist")
.desc("number of lanes active per instruction (oval all instructions)")
;
activeLanesPerGMemInstrDist
.init(1, VSZ, 4)
.name(name() + ".gmem_lanes_execution_dist")
.desc("number of active lanes per global memory instruction")
;
activeLanesPerLMemInstrDist
.init(1, VSZ, 4)
.name(name() + ".lmem_lanes_execution_dist")
.desc("number of active lanes per local memory instruction")
;
numInstrExecuted
.name(name() + ".num_instr_executed")
.desc("number of instructions executed")
;
numVecOpsExecuted
.name(name() + ".num_vec_ops_executed")
.desc("number of vec ops executed (e.g. VSZ/inst)")
;
totalCycles
.name(name() + ".num_total_cycles")
.desc("number of cycles the CU ran for")
;
ipc
.name(name() + ".ipc")
.desc("Instructions per cycle (this CU only)")
;
vpc
.name(name() + ".vpc")
.desc("Vector Operations per cycle (this CU only)")
;
numALUInstsExecuted
.name(name() + ".num_alu_insts_executed")
.desc("Number of dynamic non-GM memory insts executed")
;
wgBlockedDueLdsAllocation
.name(name() + ".wg_blocked_due_lds_alloc")
.desc("Workgroup blocked due to LDS capacity")
;
ipc = numInstrExecuted / totalCycles;
vpc = numVecOpsExecuted / totalCycles;
numTimesWgBlockedDueVgprAlloc
.name(name() + ".times_wg_blocked_due_vgpr_alloc")
.desc("Number of times WGs are blocked due to VGPR allocation per SIMD")
;
dynamicGMemInstrCnt
.name(name() + ".global_mem_instr_cnt")
.desc("dynamic global memory instructions count")
;
dynamicLMemInstrCnt
.name(name() + ".local_mem_instr_cnt")
.desc("dynamic local memory intruction count")
;
numALUInstsExecuted = numInstrExecuted - dynamicGMemInstrCnt -
dynamicLMemInstrCnt;
completedWfs
.name(name() + ".num_completed_wfs")
.desc("number of completed wavefronts")
;
numCASOps
.name(name() + ".num_CAS_ops")
.desc("number of compare and swap operations")
;
numFailedCASOps
.name(name() + ".num_failed_CAS_ops")
.desc("number of compare and swap operations that failed")
;
// register stats of pipeline stages
fetchStage.regStats();
scoreboardCheckStage.regStats();
scheduleStage.regStats();
execStage.regStats();
// register stats of memory pipeline
globalMemoryPipe.regStats();
localMemoryPipe.regStats();
}
void
ComputeUnit::updatePageDivergenceDist(Addr addr)
{
Addr virt_page_addr = roundDown(addr, TheISA::PageBytes);
if (!pagesTouched.count(virt_page_addr))
pagesTouched[virt_page_addr] = 1;
else
pagesTouched[virt_page_addr]++;
}
void
ComputeUnit::CUExitCallback::process()
{
if (computeUnit->countPages) {
std::ostream *page_stat_file =
simout.create(computeUnit->name().c_str());
*page_stat_file << "page, wavefront accesses, workitem accesses" <<
std::endl;
for (auto iter : computeUnit->pageAccesses) {
*page_stat_file << std::hex << iter.first << ",";
*page_stat_file << std::dec << iter.second.first << ",";
*page_stat_file << std::dec << iter.second.second << std::endl;
}
}
}
bool
ComputeUnit::isDone() const
{
for (int i = 0; i < numSIMDs; ++i) {
if (!isSimdDone(i)) {
return false;
}
}
bool glbMemBusRdy = true;
for (int j = 0; j < numGlbMemUnits; ++j) {
glbMemBusRdy &= vrfToGlobalMemPipeBus[j].rdy();
}
bool locMemBusRdy = true;
for (int j = 0; j < numLocMemUnits; ++j) {
locMemBusRdy &= vrfToLocalMemPipeBus[j].rdy();
}
if (!globalMemoryPipe.isGMLdRespFIFOWrRdy() ||
!globalMemoryPipe.isGMStRespFIFOWrRdy() ||
!globalMemoryPipe.isGMReqFIFOWrRdy() || !localMemoryPipe.isLMReqFIFOWrRdy()
|| !localMemoryPipe.isLMRespFIFOWrRdy() || !locMemToVrfBus.rdy() ||
!glbMemToVrfBus.rdy() || !locMemBusRdy || !glbMemBusRdy) {
return false;
}
return true;
}
int32_t
ComputeUnit::getRefCounter(const uint32_t dispatchId, const uint32_t wgId) const
{
return lds.getRefCounter(dispatchId, wgId);
}
bool
ComputeUnit::isSimdDone(uint32_t simdId) const
{
assert(simdId < numSIMDs);
for (int i=0; i < numGlbMemUnits; ++i) {
if (!vrfToGlobalMemPipeBus[i].rdy())
return false;
}
for (int i=0; i < numLocMemUnits; ++i) {
if (!vrfToLocalMemPipeBus[i].rdy())
return false;
}
if (!aluPipe[simdId].rdy()) {
return false;
}
for (int i_wf = 0; i_wf < shader->n_wf; ++i_wf){
if (wfList[simdId][i_wf]->status != Wavefront::S_STOPPED) {
return false;
}
}
return true;
}
/**
* send a general request to the LDS
* make sure to look at the return value here as your request might be
* NACK'd and returning false means that you have to have some backup plan
*/
bool
ComputeUnit::sendToLds(GPUDynInstPtr gpuDynInst)
{
// this is just a request to carry the GPUDynInstPtr
// back and forth
Request *newRequest = new Request();
newRequest->setPaddr(0x0);
// ReadReq is not evaluted by the LDS but the Packet ctor requires this
PacketPtr newPacket = new Packet(newRequest, MemCmd::ReadReq);
// This is the SenderState needed upon return
newPacket->senderState = new LDSPort::SenderState(gpuDynInst);
return ldsPort->sendTimingReq(newPacket);
}
/**
* get the result of packets sent to the LDS when they return
*/
bool
ComputeUnit::LDSPort::recvTimingResp(PacketPtr packet)
{
const ComputeUnit::LDSPort::SenderState *senderState =
dynamic_cast<ComputeUnit::LDSPort::SenderState *>(packet->senderState);
fatal_if(!senderState, "did not get the right sort of sender state");
GPUDynInstPtr gpuDynInst = senderState->getMemInst();
delete packet->senderState;
delete packet->req;
delete packet;
computeUnit->localMemoryPipe.getLMRespFIFO().push(gpuDynInst);
return true;
}
/**
* attempt to send this packet, either the port is already stalled, the request
* is nack'd and must stall or the request goes through
* when a request cannot be sent, add it to the retries queue
*/
bool
ComputeUnit::LDSPort::sendTimingReq(PacketPtr pkt)
{
ComputeUnit::LDSPort::SenderState *sender_state =
dynamic_cast<ComputeUnit::LDSPort::SenderState*>(pkt->senderState);
fatal_if(!sender_state, "packet without a valid sender state");
GPUDynInstPtr gpuDynInst M5_VAR_USED = sender_state->getMemInst();
if (isStalled()) {
fatal_if(retries.empty(), "must have retries waiting to be stalled");
retries.push(pkt);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: LDS send failed!\n",
computeUnit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId);
return false;
} else if (!MasterPort::sendTimingReq(pkt)) {
// need to stall the LDS port until a recvReqRetry() is received
// this indicates that there is more space
stallPort();
retries.push(pkt);
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: addr %#x lds req failed!\n",
computeUnit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, pkt->req->getPaddr());
return false;
} else {
DPRINTF(GPUPort, "CU%d: WF[%d][%d]: addr %#x lds req sent!\n",
computeUnit->cu_id, gpuDynInst->simdId,
gpuDynInst->wfSlotId, pkt->req->getPaddr());
return true;
}
}
/**
* the bus is telling the port that there is now space so retrying stalled
* requests should work now
* this allows the port to have a request be nack'd and then have the receiver
* say when there is space, rather than simply retrying the send every cycle
*/
void
ComputeUnit::LDSPort::recvReqRetry()
{
auto queueSize = retries.size();
DPRINTF(GPUPort, "CU%d: LDSPort recvReqRetry - %d pending requests\n",
computeUnit->cu_id, queueSize);
fatal_if(queueSize < 1,
"why was there a recvReqRetry() with no pending reqs?");
fatal_if(!isStalled(),
"recvReqRetry() happened when the port was not stalled");
unstallPort();
while (!retries.empty()) {
PacketPtr packet = retries.front();
DPRINTF(GPUPort, "CU%d: retrying LDS send\n", computeUnit->cu_id);
if (!MasterPort::sendTimingReq(packet)) {
// Stall port
stallPort();
DPRINTF(GPUPort, ": LDS send failed again\n");
break;
} else {
DPRINTF(GPUTLB, ": LDS send successful\n");
retries.pop();
}
}
}
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