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/*
* Copyright (c) 2004-2006 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* 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;
* neither the name of the copyright holders 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
* OWNER 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 <map>
#include "cpu/o3/inst_queue.hh"
#include "cpu/o3/mem_dep_unit.hh"
template <class MemDepPred, class Impl>
MemDepUnit<MemDepPred, Impl>::MemDepUnit(Params *params)
: depPred(params->SSITSize, params->LFSTSize), loadBarrier(false),
loadBarrierSN(0), storeBarrier(false), storeBarrierSN(0), iqPtr(NULL)
{
DPRINTF(MemDepUnit, "Creating MemDepUnit object.\n");
}
template <class MemDepPred, class Impl>
MemDepUnit<MemDepPred, Impl>::~MemDepUnit()
{
for (int tid=0; tid < Impl::MaxThreads; tid++) {
ListIt inst_list_it = instList[tid].begin();
MemDepHashIt hash_it;
while (!instList[tid].empty()) {
hash_it = memDepHash.find((*inst_list_it)->seqNum);
assert(hash_it != memDepHash.end());
memDepHash.erase(hash_it);
instList[tid].erase(inst_list_it++);
}
}
#ifdef DEBUG
assert(MemDepEntry::memdep_count == 0);
#endif
}
template <class MemDepPred, class Impl>
std::string
MemDepUnit<MemDepPred, Impl>::name() const
{
return "memdepunit";
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::init(Params *params, int tid)
{
DPRINTF(MemDepUnit, "Creating MemDepUnit %i object.\n",tid);
id = tid;
depPred.init(params->SSITSize, params->LFSTSize);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::regStats()
{
insertedLoads
.name(name() + ".memDep.insertedLoads")
.desc("Number of loads inserted to the mem dependence unit.");
insertedStores
.name(name() + ".memDep.insertedStores")
.desc("Number of stores inserted to the mem dependence unit.");
conflictingLoads
.name(name() + ".memDep.conflictingLoads")
.desc("Number of conflicting loads.");
conflictingStores
.name(name() + ".memDep.conflictingStores")
.desc("Number of conflicting stores.");
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::switchOut()
{
assert(instList[0].empty());
assert(instsToReplay.empty());
assert(memDepHash.empty());
// Clear any state.
for (int i = 0; i < Impl::MaxThreads; ++i) {
instList[i].clear();
}
instsToReplay.clear();
memDepHash.clear();
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::takeOverFrom()
{
// Be sure to reset all state.
loadBarrier = storeBarrier = false;
loadBarrierSN = storeBarrierSN = 0;
depPred.clear();
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::setIQ(InstructionQueue<Impl> *iq_ptr)
{
iqPtr = iq_ptr;
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::insert(DynInstPtr &inst)
{
unsigned tid = inst->threadNumber;
MemDepEntryPtr inst_entry = new MemDepEntry(inst);
// Add the MemDepEntry to the hash.
memDepHash.insert(
std::pair<InstSeqNum, MemDepEntryPtr>(inst->seqNum, inst_entry));
#ifdef DEBUG
MemDepEntry::memdep_insert++;
#endif
instList[tid].push_back(inst);
inst_entry->listIt = --(instList[tid].end());
// Check any barriers and the dependence predictor for any
// producing memrefs/stores.
InstSeqNum producing_store;
if (inst->isLoad() && loadBarrier) {
producing_store = loadBarrierSN;
} else if (inst->isStore() && storeBarrier) {
producing_store = storeBarrierSN;
} else {
producing_store = depPred.checkInst(inst->readPC());
}
MemDepEntryPtr store_entry = NULL;
// If there is a producing store, try to find the entry.
if (producing_store != 0) {
MemDepHashIt hash_it = memDepHash.find(producing_store);
if (hash_it != memDepHash.end()) {
store_entry = (*hash_it).second;
}
}
// If no store entry, then instruction can issue as soon as the registers
// are ready.
if (!store_entry) {
DPRINTF(MemDepUnit, "No dependency for inst PC "
"%#x [sn:%lli].\n", inst->readPC(), inst->seqNum);
inst_entry->memDepReady = true;
if (inst->readyToIssue()) {
inst_entry->regsReady = true;
moveToReady(inst_entry);
}
} else {
// Otherwise make the instruction dependent on the store/barrier.
DPRINTF(MemDepUnit, "Adding to dependency list; "
"inst PC %#x is dependent on [sn:%lli].\n",
inst->readPC(), producing_store);
if (inst->readyToIssue()) {
inst_entry->regsReady = true;
}
// Add this instruction to the list of dependents.
store_entry->dependInsts.push_back(inst_entry);
if (inst->isLoad()) {
++conflictingLoads;
} else {
++conflictingStores;
}
}
if (inst->isStore()) {
DPRINTF(MemDepUnit, "Inserting store PC %#x [sn:%lli].\n",
inst->readPC(), inst->seqNum);
depPred.insertStore(inst->readPC(), inst->seqNum, inst->threadNumber);
++insertedStores;
} else if (inst->isLoad()) {
++insertedLoads;
} else {
panic("Unknown type! (most likely a barrier).");
}
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::insertNonSpec(DynInstPtr &inst)
{
unsigned tid = inst->threadNumber;
MemDepEntryPtr inst_entry = new MemDepEntry(inst);
// Insert the MemDepEntry into the hash.
memDepHash.insert(
std::pair<InstSeqNum, MemDepEntryPtr>(inst->seqNum, inst_entry));
#ifdef DEBUG
MemDepEntry::memdep_insert++;
#endif
// Add the instruction to the list.
instList[tid].push_back(inst);
inst_entry->listIt = --(instList[tid].end());
// Might want to turn this part into an inline function or something.
// It's shared between both insert functions.
if (inst->isStore()) {
DPRINTF(MemDepUnit, "Inserting store PC %#x [sn:%lli].\n",
inst->readPC(), inst->seqNum);
depPred.insertStore(inst->readPC(), inst->seqNum, inst->threadNumber);
++insertedStores;
} else if (inst->isLoad()) {
++insertedLoads;
} else {
panic("Unknown type! (most likely a barrier).");
}
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::insertBarrier(DynInstPtr &barr_inst)
{
InstSeqNum barr_sn = barr_inst->seqNum;
// Memory barriers block loads and stores, write barriers only stores.
if (barr_inst->isMemBarrier()) {
loadBarrier = true;
loadBarrierSN = barr_sn;
storeBarrier = true;
storeBarrierSN = barr_sn;
DPRINTF(MemDepUnit, "Inserted a memory barrier\n");
} else if (barr_inst->isWriteBarrier()) {
storeBarrier = true;
storeBarrierSN = barr_sn;
DPRINTF(MemDepUnit, "Inserted a write barrier\n");
}
unsigned tid = barr_inst->threadNumber;
MemDepEntryPtr inst_entry = new MemDepEntry(barr_inst);
// Add the MemDepEntry to the hash.
memDepHash.insert(
std::pair<InstSeqNum, MemDepEntryPtr>(barr_sn, inst_entry));
#ifdef DEBUG
MemDepEntry::memdep_insert++;
#endif
// Add the instruction to the instruction list.
instList[tid].push_back(barr_inst);
inst_entry->listIt = --(instList[tid].end());
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::regsReady(DynInstPtr &inst)
{
DPRINTF(MemDepUnit, "Marking registers as ready for "
"instruction PC %#x [sn:%lli].\n",
inst->readPC(), inst->seqNum);
MemDepEntryPtr inst_entry = findInHash(inst);
inst_entry->regsReady = true;
if (inst_entry->memDepReady) {
DPRINTF(MemDepUnit, "Instruction has its memory "
"dependencies resolved, adding it to the ready list.\n");
moveToReady(inst_entry);
} else {
DPRINTF(MemDepUnit, "Instruction still waiting on "
"memory dependency.\n");
}
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::nonSpecInstReady(DynInstPtr &inst)
{
DPRINTF(MemDepUnit, "Marking non speculative "
"instruction PC %#x as ready [sn:%lli].\n",
inst->readPC(), inst->seqNum);
MemDepEntryPtr inst_entry = findInHash(inst);
moveToReady(inst_entry);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::reschedule(DynInstPtr &inst)
{
instsToReplay.push_back(inst);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::replay(DynInstPtr &inst)
{
DynInstPtr temp_inst;
bool found_inst = false;
// For now this replay function replays all waiting memory ops.
while (!instsToReplay.empty()) {
temp_inst = instsToReplay.front();
MemDepEntryPtr inst_entry = findInHash(temp_inst);
DPRINTF(MemDepUnit, "Replaying mem instruction PC %#x "
"[sn:%lli].\n",
temp_inst->readPC(), temp_inst->seqNum);
moveToReady(inst_entry);
if (temp_inst == inst) {
found_inst = true;
}
instsToReplay.pop_front();
}
assert(found_inst);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::completed(DynInstPtr &inst)
{
DPRINTF(MemDepUnit, "Completed mem instruction PC %#x "
"[sn:%lli].\n",
inst->readPC(), inst->seqNum);
unsigned tid = inst->threadNumber;
// Remove the instruction from the hash and the list.
MemDepHashIt hash_it = memDepHash.find(inst->seqNum);
assert(hash_it != memDepHash.end());
instList[tid].erase((*hash_it).second->listIt);
(*hash_it).second = NULL;
memDepHash.erase(hash_it);
#ifdef DEBUG
MemDepEntry::memdep_erase++;
#endif
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::completeBarrier(DynInstPtr &inst)
{
wakeDependents(inst);
completed(inst);
InstSeqNum barr_sn = inst->seqNum;
if (inst->isMemBarrier()) {
assert(loadBarrier && storeBarrier);
if (loadBarrierSN == barr_sn)
loadBarrier = false;
if (storeBarrierSN == barr_sn)
storeBarrier = false;
} else if (inst->isWriteBarrier()) {
assert(storeBarrier);
if (storeBarrierSN == barr_sn)
storeBarrier = false;
}
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::wakeDependents(DynInstPtr &inst)
{
// Only stores and barriers have dependents.
if (!inst->isStore() && !inst->isMemBarrier() && !inst->isWriteBarrier()) {
return;
}
MemDepEntryPtr inst_entry = findInHash(inst);
for (int i = 0; i < inst_entry->dependInsts.size(); ++i ) {
MemDepEntryPtr woken_inst = inst_entry->dependInsts[i];
if (!woken_inst->inst) {
// Potentially removed mem dep entries could be on this list
continue;
}
DPRINTF(MemDepUnit, "Waking up a dependent inst, "
"[sn:%lli].\n",
woken_inst->inst->seqNum);
if (woken_inst->regsReady && !woken_inst->squashed) {
moveToReady(woken_inst);
} else {
woken_inst->memDepReady = true;
}
}
inst_entry->dependInsts.clear();
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::squash(const InstSeqNum &squashed_num,
unsigned tid)
{
if (!instsToReplay.empty()) {
ListIt replay_it = instsToReplay.begin();
while (replay_it != instsToReplay.end()) {
if ((*replay_it)->threadNumber == tid &&
(*replay_it)->seqNum > squashed_num) {
instsToReplay.erase(replay_it++);
} else {
++replay_it;
}
}
}
ListIt squash_it = instList[tid].end();
--squash_it;
MemDepHashIt hash_it;
while (!instList[tid].empty() &&
(*squash_it)->seqNum > squashed_num) {
DPRINTF(MemDepUnit, "Squashing inst [sn:%lli]\n",
(*squash_it)->seqNum);
hash_it = memDepHash.find((*squash_it)->seqNum);
assert(hash_it != memDepHash.end());
(*hash_it).second->squashed = true;
(*hash_it).second = NULL;
memDepHash.erase(hash_it);
#ifdef DEBUG
MemDepEntry::memdep_erase++;
#endif
instList[tid].erase(squash_it--);
}
// Tell the dependency predictor to squash as well.
depPred.squash(squashed_num, tid);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::violation(DynInstPtr &store_inst,
DynInstPtr &violating_load)
{
DPRINTF(MemDepUnit, "Passing violating PCs to store sets,"
" load: %#x, store: %#x\n", violating_load->readPC(),
store_inst->readPC());
// Tell the memory dependence unit of the violation.
depPred.violation(violating_load->readPC(), store_inst->readPC());
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::issue(DynInstPtr &inst)
{
DPRINTF(MemDepUnit, "Issuing instruction PC %#x [sn:%lli].\n",
inst->readPC(), inst->seqNum);
depPred.issued(inst->readPC(), inst->seqNum, inst->isStore());
}
template <class MemDepPred, class Impl>
inline typename MemDepUnit<MemDepPred,Impl>::MemDepEntryPtr &
MemDepUnit<MemDepPred, Impl>::findInHash(const DynInstPtr &inst)
{
MemDepHashIt hash_it = memDepHash.find(inst->seqNum);
assert(hash_it != memDepHash.end());
return (*hash_it).second;
}
template <class MemDepPred, class Impl>
inline void
MemDepUnit<MemDepPred, Impl>::moveToReady(MemDepEntryPtr &woken_inst_entry)
{
DPRINTF(MemDepUnit, "Adding instruction [sn:%lli] "
"to the ready list.\n", woken_inst_entry->inst->seqNum);
assert(!woken_inst_entry->squashed);
iqPtr->addReadyMemInst(woken_inst_entry->inst);
}
template <class MemDepPred, class Impl>
void
MemDepUnit<MemDepPred, Impl>::dumpLists()
{
for (unsigned tid=0; tid < Impl::MaxThreads; tid++) {
cprintf("Instruction list %i size: %i\n",
tid, instList[tid].size());
ListIt inst_list_it = instList[tid].begin();
int num = 0;
while (inst_list_it != instList[tid].end()) {
cprintf("Instruction:%i\nPC:%#x\n[sn:%i]\n[tid:%i]\nIssued:%i\n"
"Squashed:%i\n\n",
num, (*inst_list_it)->readPC(),
(*inst_list_it)->seqNum,
(*inst_list_it)->threadNumber,
(*inst_list_it)->isIssued(),
(*inst_list_it)->isSquashed());
inst_list_it++;
++num;
}
}
cprintf("Memory dependence hash size: %i\n", memDepHash.size());
#ifdef DEBUG
cprintf("Memory dependence entries: %i\n", MemDepEntry::memdep_count);
#endif
}
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