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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.
*/
#include "gpu-compute/local_memory_pipeline.hh"
#include "debug/GPUMem.hh"
#include "debug/GPUPort.hh"
#include "gpu-compute/compute_unit.hh"
#include "gpu-compute/gpu_dyn_inst.hh"
#include "gpu-compute/shader.hh"
#include "gpu-compute/vector_register_file.hh"
#include "gpu-compute/wavefront.hh"
namespace gem5
{
LocalMemPipeline::LocalMemPipeline(const ComputeUnitParams &p, ComputeUnit &cu)
: computeUnit(cu), _name(cu.name() + ".LocalMemPipeline"),
lmQueueSize(p.local_mem_queue_size), stats(&cu)
{
}
void
LocalMemPipeline::exec()
{
// apply any returned shared (LDS) memory operations
GPUDynInstPtr m = !lmReturnedRequests.empty() ?
lmReturnedRequests.front() : nullptr;
bool accessVrf = true;
Wavefront *w = nullptr;
if ((m) && m->latency.rdy() && (m->isLoad() || m->isAtomicRet())) {
w = m->wavefront();
accessVrf = w->computeUnit->vrf[w->simdId]->
canScheduleWriteOperandsFromLoad(w, m);
}
if (!lmReturnedRequests.empty() && m->latency.rdy() && accessVrf &&
computeUnit.locMemToVrfBus.rdy()
&& (computeUnit.shader->coissue_return
|| computeUnit.vectorSharedMemUnit.rdy())) {
lmReturnedRequests.pop();
w = m->wavefront();
DPRINTF(GPUMem, "CU%d: WF[%d][%d]: Completing local mem instr %s\n",
m->cu_id, m->simdId, m->wfSlotId, m->disassemble());
m->completeAcc(m);
w->decLGKMInstsIssued();
if (m->isLoad() || m->isAtomicRet()) {
w->computeUnit->vrf[w->simdId]->
scheduleWriteOperandsFromLoad(w, m);
}
// Decrement outstanding request count
computeUnit.shader->ScheduleAdd(&w->outstandingReqs, m->time, -1);
if (m->isStore() || m->isAtomic()) {
computeUnit.shader->ScheduleAdd(&w->outstandingReqsWrLm,
m->time, -1);
}
if (m->isLoad() || m->isAtomic()) {
computeUnit.shader->ScheduleAdd(&w->outstandingReqsRdLm,
m->time, -1);
}
// Mark write bus busy for appropriate amount of time
computeUnit.locMemToVrfBus.set(m->time);
if (computeUnit.shader->coissue_return == 0)
w->computeUnit->vectorSharedMemUnit.set(m->time);
}
// If pipeline has executed a local memory instruction
// execute local memory packet and issue the packets
// to LDS
if (!lmIssuedRequests.empty() && lmReturnedRequests.size() < lmQueueSize) {
GPUDynInstPtr m = lmIssuedRequests.front();
bool returnVal = computeUnit.sendToLds(m);
if (!returnVal) {
DPRINTF(GPUPort, "packet was nack'd and put in retry queue");
}
lmIssuedRequests.pop();
}
}
void
LocalMemPipeline::issueRequest(GPUDynInstPtr gpuDynInst)
{
Wavefront *wf = gpuDynInst->wavefront();
if (gpuDynInst->isLoad()) {
wf->rdLmReqsInPipe--;
wf->outstandingReqsRdLm++;
} else if (gpuDynInst->isStore()) {
wf->wrLmReqsInPipe--;
wf->outstandingReqsWrLm++;
} else {
// Atomic, both read and write
wf->rdLmReqsInPipe--;
wf->outstandingReqsRdLm++;
wf->wrLmReqsInPipe--;
wf->outstandingReqsWrLm++;
}
wf->outstandingReqs++;
wf->validateRequestCounters();
gpuDynInst->setAccessTime(curTick());
lmIssuedRequests.push(gpuDynInst);
}
LocalMemPipeline::
LocalMemPipelineStats::LocalMemPipelineStats(statistics::Group *parent)
: statistics::Group(parent, "LocalMemPipeline"),
ADD_STAT(loadVrfBankConflictCycles, "total number of cycles LDS data "
"are delayed before updating the VRF")
{
}
} // namespace gem5