/*
* 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.
*
* Authors: Kevin Lim
* Korey Sewell
*/
#include <limits>
#include <vector>
#include "cpu/o3/fu_pool.hh"
#include "cpu/o3/inst_queue.hh"
#include "enums/OpClass.hh"
#include "sim/core.hh"
#include "params/DerivO3CPU.hh"
template <class Impl>
InstructionQueue<Impl>::FUCompletion::FUCompletion(DynInstPtr &_inst,
int fu_idx, InstructionQueue<Impl> *iq_ptr)
: Event(Stat_Event_Pri), inst(_inst), fuIdx(fu_idx), iqPtr(iq_ptr),
freeFU(false)
{
this->setFlags(Event::AutoDelete);
}
template <class Impl>
void
InstructionQueue<Impl>::FUCompletion::process()
{
iqPtr->processFUCompletion(inst, freeFU ? fuIdx : -1);
inst = NULL;
}
template <class Impl>
const char *
InstructionQueue<Impl>::FUCompletion::description() const
{
return "Functional unit completion";
}
template <class Impl>
InstructionQueue<Impl>::InstructionQueue(O3CPU *cpu_ptr, IEW *iew_ptr,
DerivO3CPUParams *params)
: cpu(cpu_ptr),
iewStage(iew_ptr),
fuPool(params->fuPool),
numEntries(params->numIQEntries),
totalWidth(params->issueWidth),
numPhysIntRegs(params->numPhysIntRegs),
numPhysFloatRegs(params->numPhysFloatRegs),
commitToIEWDelay(params->commitToIEWDelay)
{
assert(fuPool);
switchedOut = false;
numThreads = params->numThreads;
// Set the number of physical registers as the number of int + float
numPhysRegs = numPhysIntRegs + numPhysFloatRegs;
//Create an entry for each physical register within the
//dependency graph.
dependGraph.resize(numPhysRegs);
// Resize the register scoreboard.
regScoreboard.resize(numPhysRegs);
//Initialize Mem Dependence Units
for (int i = 0; i < numThreads; i++) {
memDepUnit[i].init(params,i);
memDepUnit[i].setIQ(this);
}
resetState();
std::string policy = params->smtIQPolicy;
//Convert string to lowercase
std::transform(policy.begin(), policy.end(), policy.begin(),
(int(*)(int)) tolower);
//Figure out resource sharing policy
if (policy == "dynamic") {
iqPolicy = Dynamic;
//Set Max Entries to Total ROB Capacity
for (int i = 0; i < numThreads; i++) {
maxEntries[i] = numEntries;
}
} else if (policy == "partitioned") {
iqPolicy = Partitioned;
//@todo:make work if part_amt doesnt divide evenly.
int part_amt = numEntries / numThreads;
//Divide ROB up evenly
for (int i = 0; i < numThreads; i++) {
maxEntries[i] = part_amt;
}
DPRINTF(IQ, "IQ sharing policy set to Partitioned:"
"%i entries per thread.\n",part_amt);
} else if (policy == "threshold") {
iqPolicy = Threshold;
double threshold = (double)params->smtIQThreshold / 100;
int thresholdIQ = (int)((double)threshold * numEntries);
//Divide up by threshold amount
for (int i = 0; i < numThreads; i++) {
maxEntries[i] = thresholdIQ;
}
DPRINTF(IQ, "IQ sharing policy set to Threshold:"
"%i entries per thread.\n",thresholdIQ);
} else {
assert(0 && "Invalid IQ Sharing Policy.Options Are:{Dynamic,"
"Partitioned, Threshold}");
}
}
template <class Impl>
InstructionQueue<Impl>::~InstructionQueue()
{
dependGraph.reset();
#ifdef DEBUG
cprintf("Nodes traversed: %i, removed: %i\n",
dependGraph.nodesTraversed, dependGraph.nodesRemoved);
#endif
}
template <class Impl>
std::string
InstructionQueue<Impl>::name() const
{
return cpu->name() + ".iq";
}
template <class Impl>
void
InstructionQueue<Impl>::regStats()
{
using namespace Stats;
iqInstsAdded
.name(name() + ".iqInstsAdded")
.desc("Number of instructions added to the IQ (excludes non-spec)")
.prereq(iqInstsAdded);
iqNonSpecInstsAdded
.name(name() + ".iqNonSpecInstsAdded")
.desc("Number of non-speculative instructions added to the IQ")
.prereq(iqNonSpecInstsAdded);
iqInstsIssued
.name(name() + ".iqInstsIssued")
.desc("Number of instructions issued")
.prereq(iqInstsIssued);
iqIntInstsIssued
.name(name() + ".iqIntInstsIssued")
.desc("Number of integer instructions issued")
.prereq(iqIntInstsIssued);
iqFloatInstsIssued
.name(name() + ".iqFloatInstsIssued")
.desc("Number of float instructions issued")
.prereq(iqFloatInstsIssued);
iqBranchInstsIssued
.name(name() + ".iqBranchInstsIssued")
.desc("Number of branch instructions issued")
.prereq(iqBranchInstsIssued);
iqMemInstsIssued
.name(name() + ".iqMemInstsIssued")
.desc("Number of memory instructions issued")
.prereq(iqMemInstsIssued);
iqMiscInstsIssued
.name(name() + ".iqMiscInstsIssued")
.desc("Number of miscellaneous instructions issued")
.prereq(iqMiscInstsIssued);
iqSquashedInstsIssued
.name(name() + ".iqSquashedInstsIssued")
.desc("Number of squashed instructions issued")
.prereq(iqSquashedInstsIssued);
iqSquashedInstsExamined
.name(name() + ".iqSquashedInstsExamined")
.desc("Number of squashed instructions iterated over during squash;"
" mainly for profiling")
.prereq(iqSquashedInstsExamined);
iqSquashedOperandsExamined
.name(name() + ".iqSquashedOperandsExamined")
.desc("Number of squashed operands that are examined and possibly "
"removed from graph")
.prereq(iqSquashedOperandsExamined);
iqSquashedNonSpecRemoved
.name(name() + ".iqSquashedNonSpecRemoved")
.desc("Number of squashed non-spec instructions that were removed")
.prereq(iqSquashedNonSpecRemoved);
/*
queueResDist
.init(Num_OpClasses, 0, 99, 2)
.name(name() + ".IQ:residence:")
.desc("cycles from dispatch to issue")
.flags(total | pdf | cdf )
;
for (int i = 0; i < Num_OpClasses; ++i) {
queueResDist.subname(i, opClassStrings[i]);
}
*/
numIssuedDist
.init(0,totalWidth,1)
.name(name() + ".ISSUE:issued_per_cycle")
.desc("Number of insts issued each cycle")
.flags(pdf)
;
/*
dist_unissued
.init(Num_OpClasses+2)
.name(name() + ".ISSUE:unissued_cause")
.desc("Reason ready instruction not issued")
.flags(pdf | dist)
;
for (int i=0; i < (Num_OpClasses + 2); ++i) {
dist_unissued.subname(i, unissued_names[i]);
}
*/
statIssuedInstType
.init(numThreads,Enums::Num_OpClass)
.name(name() + ".ISSUE:FU_type")
.desc("Type of FU issued")
.flags(total | pdf | dist)
;
statIssuedInstType.ysubnames(Enums::OpClassStrings);
//
// How long did instructions for a particular FU type wait prior to issue
//
/*
issueDelayDist
.init(Num_OpClasses,0,99,2)
.name(name() + ".ISSUE:")
.desc("cycles from operands ready to issue")
.flags(pdf | cdf)
;
for (int i=0; i<Num_OpClasses; ++i) {
std::stringstream subname;
subname << opClassStrings[i] << "_delay";
issueDelayDist.subname(i, subname.str());
}
*/
issueRate
.name(name() + ".ISSUE:rate")
.desc("Inst issue rate")
.flags(total)
;
issueRate = iqInstsIssued / cpu->numCycles;
statFuBusy
.init(Num_OpClasses)
.name(name() + ".ISSUE:fu_full")
.desc("attempts to use FU when none available")
.flags(pdf | dist)
;
for (int i=0; i < Num_OpClasses; ++i) {
statFuBusy.subname(i, Enums::OpClassStrings[i]);
}
fuBusy
.init(numThreads)
.name(name() + ".ISSUE:fu_busy_cnt")
.desc("FU busy when requested")
.flags(total)
;
fuBusyRate
.name(name() + ".ISSUE:fu_busy_rate")
.desc("FU busy rate (busy events/executed inst)")
.flags(total)
;
fuBusyRate = fuBusy / iqInstsIssued;
for ( int i=0; i < numThreads; i++) {
// Tell mem dependence unit to reg stats as well.
memDepUnit[i].regStats();
}
}
template <class Impl>
void
InstructionQueue<Impl>::resetState()
{
//Initialize thread IQ counts
for (int i = 0; i <numThreads; i++) {
count[i] = 0;
instList[i].clear();
}
// Initialize the number of free IQ entries.
freeEntries = numEntries;
// Note that in actuality, the registers corresponding to the logical
// registers start off as ready. However this doesn't matter for the
// IQ as the instruction should have been correctly told if those
// registers are ready in rename. Thus it can all be initialized as
// unready.
for (int i = 0; i < numPhysRegs; ++i) {
regScoreboard[i] = false;
}
for (int i = 0; i < numThreads; ++i) {
squashedSeqNum[i] = 0;
}
for (int i = 0; i < Num_OpClasses; ++i) {
while (!readyInsts[i].empty())
readyInsts[i].pop();
queueOnList[i] = false;
readyIt[i] = listOrder.end();
}
nonSpecInsts.clear();
listOrder.clear();
}
template <class Impl>
void
InstructionQueue<Impl>::setActiveThreads(std::list<unsigned> *at_ptr)
{
activeThreads = at_ptr;
}
template <class Impl>
void
InstructionQueue<Impl>::setIssueToExecuteQueue(TimeBuffer<IssueStruct> *i2e_ptr)
{
issueToExecuteQueue = i2e_ptr;
}
template <class Impl>
void
InstructionQueue<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
{
timeBuffer = tb_ptr;
fromCommit = timeBuffer->getWire(-commitToIEWDelay);
}
template <class Impl>
void
InstructionQueue<Impl>::switchOut()
{
/*
if (!instList[0].empty() || (numEntries != freeEntries) ||
!readyInsts[0].empty() || !nonSpecInsts.empty() || !listOrder.empty()) {
dumpInsts();
// assert(0);
}
*/
resetState();
dependGraph.reset();
instsToExecute.clear();
switchedOut = true;
for (int i = 0; i < numThreads; ++i) {
memDepUnit[i].switchOut();
}
}
template <class Impl>
void
InstructionQueue<Impl>::takeOverFrom()
{
switchedOut = false;
}
template <class Impl>
int
InstructionQueue<Impl>::entryAmount(int num_threads)
{
if (iqPolicy == Partitioned) {
return numEntries / num_threads;
} else {
return 0;
}
}
template <class Impl>
void
InstructionQueue<Impl>::resetEntries()
{
if (iqPolicy != Dynamic || numThreads > 1) {
int active_threads = activeThreads->size();
std::list<unsigned>::iterator threads = activeThreads->begin();
std::list<unsigned>::iterator end = activeThreads->end();
while (threads != end) {
unsigned tid = *threads++;
if (iqPolicy == Partitioned) {
maxEntries[tid] = numEntries / active_threads;
} else if(iqPolicy == Threshold && active_threads == 1) {
maxEntries[tid] = numEntries;
}
}
}
}
template <class Impl>
unsigned
InstructionQueue<Impl>::numFreeEntries()
{
return freeEntries;
}
template <class Impl>
unsigned
InstructionQueue<Impl>::numFreeEntries(unsigned tid)
{
return maxEntries[tid] - count[tid];
}
// Might want to do something more complex if it knows how many instructions
// will be issued this cycle.
template <class Impl>
bool
InstructionQueue<Impl>::isFull()
{
if (freeEntries == 0) {
return(true);
} else {
return(false);
}
}
template <class Impl>
bool
InstructionQueue<Impl>::isFull(unsigned tid)
{
if (numFreeEntries(tid) == 0) {
return(true);
} else {
return(false);
}
}
template <class Impl>
bool
InstructionQueue<Impl>::hasReadyInsts()
{
if (!listOrder.empty()) {
return true;
}
for (int i = 0; i < Num_OpClasses; ++i) {
if (!readyInsts[i].empty()) {
return true;
}
}
return false;
}
template <class Impl>
void
InstructionQueue<Impl>::insert(DynInstPtr &new_inst)
{
// Make sure the instruction is valid
assert(new_inst);
DPRINTF(IQ, "Adding instruction [sn:%lli] PC %#x to the IQ.\n",
new_inst->seqNum, new_inst->readPC());
assert(freeEntries != 0);
instList[new_inst->threadNumber].push_back(new_inst);
--freeEntries;
new_inst->setInIQ();
// Look through its source registers (physical regs), and mark any
// dependencies.
addToDependents(new_inst);
// Have this instruction set itself as the producer of its destination
// register(s).
addToProducers(new_inst);
if (new_inst->isMemRef()) {
memDepUnit[new_inst->threadNumber].insert(new_inst);
} else {
addIfReady(new_inst);
}
++iqInstsAdded;
count[new_inst->threadNumber]++;
assert(freeEntries == (numEntries - countInsts()));
}
template <class Impl>
void
InstructionQueue<Impl>::insertNonSpec(DynInstPtr &new_inst)
{
// @todo: Clean up this code; can do it by setting inst as unable
// to issue, then calling normal insert on the inst.
assert(new_inst);
nonSpecInsts[new_inst->seqNum] = new_inst;
DPRINTF(IQ, "Adding non-speculative instruction [sn:%lli] PC %#x "
"to the IQ.\n",
new_inst->seqNum, new_inst->readPC());
assert(freeEntries != 0);
instList[new_inst->threadNumber].push_back(new_inst);
--freeEntries;
new_inst->setInIQ();
// Have this instruction set itself as the producer of its destination
// register(s).
addToProducers(new_inst);
// If it's a memory instruction, add it to the memory dependency
// unit.
if (new_inst->isMemRef()) {
memDepUnit[new_inst->threadNumber].insertNonSpec(new_inst);
}
++iqNonSpecInstsAdded;
count[new_inst->threadNumber]++;
assert(freeEntries == (numEntries - countInsts()));
}
template <class Impl>
void
InstructionQueue<Impl>::insertBarrier(DynInstPtr &barr_inst)
{
memDepUnit[barr_inst->threadNumber].insertBarrier(barr_inst);
insertNonSpec(barr_inst);
}
template <class Impl>
typename Impl::DynInstPtr
InstructionQueue<Impl>::getInstToExecute()
{
assert(!instsToExecute.empty());
DynInstPtr inst = instsToExecute.front();
instsToExecute.pop_front();
return inst;
}
template <class Impl>
void
InstructionQueue<Impl>::addToOrderList(OpClass op_class)
{
assert(!readyInsts[op_class].empty());
ListOrderEntry queue_entry;
queue_entry.queueType = op_class;
queue_entry.oldestInst = readyInsts[op_class].top()->seqNum;
ListOrderIt list_it = listOrder.begin();
ListOrderIt list_end_it = listOrder.end();
while (list_it != list_end_it) {
if ((*list_it).oldestInst > queue_entry.oldestInst) {
break;
}
list_it++;
}
readyIt[op_class] = listOrder.insert(list_it, queue_entry);
queueOnList[op_class] = true;
}
template <class Impl>
void
InstructionQueue<Impl>::moveToYoungerInst(ListOrderIt list_order_it)
{
// Get iterator of next item on the list
// Delete the original iterator
// Determine if the next item is either the end of the list or younger
// than the new instruction. If so, then add in a new iterator right here.
// If not, then move along.
ListOrderEntry queue_entry;
OpClass op_class = (*list_order_it).queueType;
ListOrderIt next_it = list_order_it;
++next_it;
queue_entry.queueType = op_class;
queue_entry.oldestInst = readyInsts[op_class].top()->seqNum;
while (next_it != listOrder.end() &&
(*next_it).oldestInst < queue_entry.oldestInst) {
++next_it;
}
readyIt[op_class] = listOrder.insert(next_it, queue_entry);
}
template <class Impl>
void
InstructionQueue<Impl>::processFUCompletion(DynInstPtr &inst, int fu_idx)
{
DPRINTF(IQ, "Processing FU completion [sn:%lli]\n", inst->seqNum);
// The CPU could have been sleeping until this op completed (*extremely*
// long latency op). Wake it if it was. This may be overkill.
if (isSwitchedOut()) {
DPRINTF(IQ, "FU completion not processed, IQ is switched out [sn:%lli]\n",
inst->seqNum);
return;
}
iewStage->wakeCPU();
if (fu_idx > -1)
fuPool->freeUnitNextCycle(fu_idx);
// @todo: Ensure that these FU Completions happen at the beginning
// of a cycle, otherwise they could add too many instructions to
// the queue.
issueToExecuteQueue->access(-1)->size++;
instsToExecute.push_back(inst);
}
// @todo: Figure out a better way to remove the squashed items from the
// lists. Checking the top item of each list to see if it's squashed
// wastes time and forces jumps.
template <class Impl>
void
InstructionQueue<Impl>::scheduleReadyInsts()
{
DPRINTF(IQ, "Attempting to schedule ready instructions from "
"the IQ.\n");
IssueStruct *i2e_info = issueToExecuteQueue->access(0);
// Have iterator to head of the list
// While I haven't exceeded bandwidth or reached the end of the list,
// Try to get a FU that can do what this op needs.
// If successful, change the oldestInst to the new top of the list, put
// the queue in the proper place in the list.
// Increment the iterator.
// This will avoid trying to schedule a certain op class if there are no
// FUs that handle it.
ListOrderIt order_it = listOrder.begin();
ListOrderIt order_end_it = listOrder.end();
int total_issued = 0;
while (total_issued < totalWidth &&
iewStage->canIssue() &&
order_it != order_end_it) {
OpClass op_class = (*order_it).queueType;
assert(!readyInsts[op_class].empty());
DynInstPtr issuing_inst = readyInsts[op_class].top();
assert(issuing_inst->seqNum == (*order_it).oldestInst);
if (issuing_inst->isSquashed()) {
readyInsts[op_class].pop();
if (!readyInsts[op_class].empty()) {
moveToYoungerInst(order_it);
} else {
readyIt[op_class] = listOrder.end();
queueOnList[op_class] = false;
}
listOrder.erase(order_it++);
++iqSquashedInstsIssued;
continue;
}
int idx = -2;
int op_latency = 1;
int tid = issuing_inst->threadNumber;
if (op_class != No_OpClass) {
idx = fuPool->getUnit(op_class);
if (idx > -1) {
op_latency = fuPool->getOpLatency(op_class);
}
}
// If we have an instruction that doesn't require a FU, or a
// valid FU, then schedule for execution.
if (idx == -2 || idx != -1) {
if (op_latency == 1) {
i2e_info->size++;
instsToExecute.push_back(issuing_inst);
// Add the FU onto the list of FU's to be freed next
// cycle if we used one.
if (idx >= 0)
fuPool->freeUnitNextCycle(idx);
} else {
int issue_latency = fuPool->getIssueLatency(op_class);
// Generate completion event for the FU
FUCompletion *execution = new FUCompletion(issuing_inst,
idx, this);
cpu->schedule(execution, curTick + cpu->ticks(op_latency - 1));
// @todo: Enforce that issue_latency == 1 or op_latency
if (issue_latency > 1) {
// If FU isn't pipelined, then it must be freed
// upon the execution completing.
execution->setFreeFU();
} else {
// Add the FU onto the list of FU's to be freed next cycle.
fuPool->freeUnitNextCycle(idx);
}
}
DPRINTF(IQ, "Thread %i: Issuing instruction PC %#x "
"[sn:%lli]\n",
tid, issuing_inst->readPC(),
issuing_inst->seqNum);
readyInsts[op_class].pop();
if (!readyInsts[op_class].empty()) {
moveToYoungerInst(order_it);
} else {
readyIt[op_class] = listOrder.end();
queueOnList[op_class] = false;
}
issuing_inst->setIssued();
++total_issued;
if (!issuing_inst->isMemRef()) {
// Memory instructions can not be freed from the IQ until they
// complete.
++freeEntries;
count[tid]--;
issuing_inst->clearInIQ();
} else {
memDepUnit[tid].issue(issuing_inst);
}
listOrder.erase(order_it++);
statIssuedInstType[tid][op_class]++;
iewStage->incrWb(issuing_inst->seqNum);
} else {
statFuBusy[op_class]++;
fuBusy[tid]++;
++order_it;
}
}
numIssuedDist.sample(total_issued);
iqInstsIssued+= total_issued;
// If we issued any instructions, tell the CPU we had activity.
if (total_issued) {
cpu->activityThisCycle();
} else {
DPRINTF(IQ, "Not able to schedule any instructions.\n");
}
}
template <class Impl>
void
InstructionQueue<Impl>::scheduleNonSpec(const InstSeqNum &inst)
{
DPRINTF(IQ, "Marking nonspeculative instruction [sn:%lli] as ready "
"to execute.\n", inst);
NonSpecMapIt inst_it = nonSpecInsts.find(inst);
assert(inst_it != nonSpecInsts.end());
unsigned tid = (*inst_it).second->threadNumber;
(*inst_it).second->setAtCommit();
(*inst_it).second->setCanIssue();
if (!(*inst_it).second->isMemRef()) {
addIfReady((*inst_it).second);
} else {
memDepUnit[tid].nonSpecInstReady((*inst_it).second);
}
(*inst_it).second = NULL;
nonSpecInsts.erase(inst_it);
}
template <class Impl>
void
InstructionQueue<Impl>::commit(const InstSeqNum &inst, unsigned tid)
{
DPRINTF(IQ, "[tid:%i]: Committing instructions older than [sn:%i]\n",
tid,inst);
ListIt iq_it = instList[tid].begin();
while (iq_it != instList[tid].end() &&
(*iq_it)->seqNum <= inst) {
++iq_it;
instList[tid].pop_front();
}
assert(freeEntries == (numEntries - countInsts()));
}
template <class Impl>
int
InstructionQueue<Impl>::wakeDependents(DynInstPtr &completed_inst)
{
int dependents = 0;
DPRINTF(IQ, "Waking dependents of completed instruction.\n");
assert(!completed_inst->isSquashed());
// Tell the memory dependence unit to wake any dependents on this
// instruction if it is a memory instruction. Also complete the memory
// instruction at this point since we know it executed without issues.
// @todo: Might want to rename "completeMemInst" to something that
// indicates that it won't need to be replayed, and call this
// earlier. Might not be a big deal.
if (completed_inst->isMemRef()) {
memDepUnit[completed_inst->threadNumber].wakeDependents(completed_inst);
completeMemInst(completed_inst);
} else if (completed_inst->isMemBarrier() ||
completed_inst->isWriteBarrier()) {
memDepUnit[completed_inst->threadNumber].completeBarrier(completed_inst);
}
for (int dest_reg_idx = 0;
dest_reg_idx < completed_inst->numDestRegs();
dest_reg_idx++)
{
PhysRegIndex dest_reg =
completed_inst->renamedDestRegIdx(dest_reg_idx);
// Special case of uniq or control registers. They are not
// handled by the IQ and thus have no dependency graph entry.
// @todo Figure out a cleaner way to handle this.
if (dest_reg >= numPhysRegs) {
continue;
}
DPRINTF(IQ, "Waking any dependents on register %i.\n",
(int) dest_reg);
//Go through the dependency chain, marking the registers as
//ready within the waiting instructions.
DynInstPtr dep_inst = dependGraph.pop(dest_reg);
while (dep_inst) {
DPRINTF(IQ, "Waking up a dependent instruction, PC%#x.\n",
dep_inst->readPC());
// Might want to give more information to the instruction
// so that it knows which of its source registers is
// ready. However that would mean that the dependency
// graph entries would need to hold the src_reg_idx.
dep_inst->markSrcRegReady();
addIfReady(dep_inst);
dep_inst = dependGraph.pop(dest_reg);
++dependents;
}
// Reset the head node now that all of its dependents have
// been woken up.
assert(dependGraph.empty(dest_reg));
dependGraph.clearInst(dest_reg);
// Mark the scoreboard as having that register ready.
regScoreboard[dest_reg] = true;
}
return dependents;
}
template <class Impl>
void
InstructionQueue<Impl>::addReadyMemInst(DynInstPtr &ready_inst)
{
OpClass op_class = ready_inst->opClass();
readyInsts[op_class].push(ready_inst);
// Will need to reorder the list if either a queue is not on the list,
// or it has an older instruction than last time.
if (!queueOnList[op_class]) {
addToOrderList(op_class);
} else if (readyInsts[op_class].top()->seqNum <
(*readyIt[op_class]).oldestInst) {
listOrder.erase(readyIt[op_class]);
addToOrderList(op_class);
}
DPRINTF(IQ, "Instruction is ready to issue, putting it onto "
"the ready list, PC %#x opclass:%i [sn:%lli].\n",
ready_inst->readPC(), op_class, ready_inst->seqNum);
}
template <class Impl>
void
InstructionQueue<Impl>::rescheduleMemInst(DynInstPtr &resched_inst)
{
DPRINTF(IQ, "Rescheduling mem inst [sn:%lli]\n", resched_inst->seqNum);
resched_inst->clearCanIssue();
memDepUnit[resched_inst->threadNumber].reschedule(resched_inst);
}
template <class Impl>
void
InstructionQueue<Impl>::replayMemInst(DynInstPtr &replay_inst)
{
memDepUnit[replay_inst->threadNumber].replay(replay_inst);
}
template <class Impl>
void
InstructionQueue<Impl>::completeMemInst(DynInstPtr &completed_inst)
{
int tid = completed_inst->threadNumber;
DPRINTF(IQ, "Completing mem instruction PC:%#x [sn:%lli]\n",
completed_inst->readPC(), completed_inst->seqNum);
++freeEntries;
completed_inst->memOpDone = true;
memDepUnit[tid].completed(completed_inst);
count[tid]--;
}
template <class Impl>
void
InstructionQueue<Impl>::violation(DynInstPtr &store,
DynInstPtr &faulting_load)
{
memDepUnit[store->threadNumber].violation(store, faulting_load);
}
template <class Impl>
void
InstructionQueue<Impl>::squash(unsigned tid)
{
DPRINTF(IQ, "[tid:%i]: Starting to squash instructions in "
"the IQ.\n", tid);
// Read instruction sequence number of last instruction out of the
// time buffer.
squashedSeqNum[tid] = fromCommit->commitInfo[tid].doneSeqNum;
// Call doSquash if there are insts in the IQ
if (count[tid] > 0) {
doSquash(tid);
}
// Also tell the memory dependence unit to squash.
memDepUnit[tid].squash(squashedSeqNum[tid], tid);
}
template <class Impl>
void
InstructionQueue<Impl>::doSquash(unsigned tid)
{
// Start at the tail.
ListIt squash_it = instList[tid].end();
--squash_it;
DPRINTF(IQ, "[tid:%i]: Squashing until sequence number %i!\n",
tid, squashedSeqNum[tid]);
// Squash any instructions younger than the squashed sequence number
// given.
while (squash_it != instList[tid].end() &&
(*squash_it)->seqNum > squashedSeqNum[tid]) {
DynInstPtr squashed_inst = (*squash_it);
// Only handle the instruction if it actually is in the IQ and
// hasn't already been squashed in the IQ.
if (squashed_inst->threadNumber != tid ||
squashed_inst->isSquashedInIQ()) {
--squash_it;
continue;
}
if (!squashed_inst->isIssued() ||
(squashed_inst->isMemRef() &&
!squashed_inst->memOpDone)) {
DPRINTF(IQ, "[tid:%i]: Instruction [sn:%lli] PC %#x "
"squashed.\n",
tid, squashed_inst->seqNum, squashed_inst->readPC());
// Remove the instruction from the dependency list.
if (!squashed_inst->isNonSpeculative() &&
!squashed_inst->isStoreConditional() &&
!squashed_inst->isMemBarrier() &&
!squashed_inst->isWriteBarrier()) {
for (int src_reg_idx = 0;
src_reg_idx < squashed_inst->numSrcRegs();
src_reg_idx++)
{
PhysRegIndex src_reg =
squashed_inst->renamedSrcRegIdx(src_reg_idx);
// Only remove it from the dependency graph if it
// was placed there in the first place.
// Instead of doing a linked list traversal, we
// can just remove these squashed instructions
// either at issue time, or when the register is
// overwritten. The only downside to this is it
// leaves more room for error.
if (!squashed_inst->isReadySrcRegIdx(src_reg_idx) &&
src_reg < numPhysRegs) {
dependGraph.remove(src_reg, squashed_inst);
}
++iqSquashedOperandsExamined;
}
} else if (!squashed_inst->isStoreConditional() ||
!squashed_inst->isCompleted()) {
NonSpecMapIt ns_inst_it =
nonSpecInsts.find(squashed_inst->seqNum);
assert(ns_inst_it != nonSpecInsts.end());
if (ns_inst_it == nonSpecInsts.end()) {
assert(squashed_inst->getFault() != NoFault);
} else {
(*ns_inst_it).second = NULL;
nonSpecInsts.erase(ns_inst_it);
++iqSquashedNonSpecRemoved;
}
}
// Might want to also clear out the head of the dependency graph.
// Mark it as squashed within the IQ.
squashed_inst->setSquashedInIQ();
// @todo: Remove this hack where several statuses are set so the
// inst will flow through the rest of the pipeline.
squashed_inst->setIssued();
squashed_inst->setCanCommit();
squashed_inst->clearInIQ();
//Update Thread IQ Count
count[squashed_inst->threadNumber]--;
++freeEntries;
}
instList[tid].erase(squash_it--);
++iqSquashedInstsExamined;
}
}
template <class Impl>
bool
InstructionQueue<Impl>::addToDependents(DynInstPtr &new_inst)
{
// Loop through the instruction's source registers, adding
// them to the dependency list if they are not ready.
int8_t total_src_regs = new_inst->numSrcRegs();
bool return_val = false;
for (int src_reg_idx = 0;
src_reg_idx < total_src_regs;
src_reg_idx++)
{
// Only add it to the dependency graph if it's not ready.
if (!new_inst->isReadySrcRegIdx(src_reg_idx)) {
PhysRegIndex src_reg = new_inst->renamedSrcRegIdx(src_reg_idx);
// Check the IQ's scoreboard to make sure the register
// hasn't become ready while the instruction was in flight
// between stages. Only if it really isn't ready should
// it be added to the dependency graph.
if (src_reg >= numPhysRegs) {
continue;
} else if (regScoreboard[src_reg] == false) {
DPRINTF(IQ, "Instruction PC %#x has src reg %i that "
"is being added to the dependency chain.\n",
new_inst->readPC(), src_reg);
dependGraph.insert(src_reg, new_inst);
// Change the return value to indicate that something
// was added to the dependency graph.
return_val = true;
} else {
DPRINTF(IQ, "Instruction PC %#x has src reg %i that "
"became ready before it reached the IQ.\n",
new_inst->readPC(), src_reg);
// Mark a register ready within the instruction.
new_inst->markSrcRegReady(src_reg_idx);
}
}
}
return return_val;
}
template <class Impl>
void
InstructionQueue<Impl>::addToProducers(DynInstPtr &new_inst)
{
// Nothing really needs to be marked when an instruction becomes
// the producer of a register's value, but for convenience a ptr
// to the producing instruction will be placed in the head node of
// the dependency links.
int8_t total_dest_regs = new_inst->numDestRegs();
for (int dest_reg_idx = 0;
dest_reg_idx < total_dest_regs;
dest_reg_idx++)
{
PhysRegIndex dest_reg = new_inst->renamedDestRegIdx(dest_reg_idx);
// Instructions that use the misc regs will have a reg number
// higher than the normal physical registers. In this case these
// registers are not renamed, and there is no need to track
// dependencies as these instructions must be executed at commit.
if (dest_reg >= numPhysRegs) {
continue;
}
if (!dependGraph.empty(dest_reg)) {
dependGraph.dump();
panic("Dependency graph %i not empty!", dest_reg);
}
dependGraph.setInst(dest_reg, new_inst);
// Mark the scoreboard to say it's not yet ready.
regScoreboard[dest_reg] = false;
}
}
template <class Impl>
void
InstructionQueue<Impl>::addIfReady(DynInstPtr &inst)
{
// If the instruction now has all of its source registers
// available, then add it to the list of ready instructions.
if (inst->readyToIssue()) {
//Add the instruction to the proper ready list.
if (inst->isMemRef()) {
DPRINTF(IQ, "Checking if memory instruction can issue.\n");
// Message to the mem dependence unit that this instruction has
// its registers ready.
memDepUnit[inst->threadNumber].regsReady(inst);
return;
}
OpClass op_class = inst->opClass();
DPRINTF(IQ, "Instruction is ready to issue, putting it onto "
"the ready list, PC %#x opclass:%i [sn:%lli].\n",
inst->readPC(), op_class, inst->seqNum);
readyInsts[op_class].push(inst);
// Will need to reorder the list if either a queue is not on the list,
// or it has an older instruction than last time.
if (!queueOnList[op_class]) {
addToOrderList(op_class);
} else if (readyInsts[op_class].top()->seqNum <
(*readyIt[op_class]).oldestInst) {
listOrder.erase(readyIt[op_class]);
addToOrderList(op_class);
}
}
}
template <class Impl>
int
InstructionQueue<Impl>::countInsts()
{
#if 0
//ksewell:This works but definitely could use a cleaner write
//with a more intuitive way of counting. Right now it's
//just brute force ....
// Change the #if if you want to use this method.
int total_insts = 0;
for (int i = 0; i < numThreads; ++i) {
ListIt count_it = instList[i].begin();
while (count_it != instList[i].end()) {
if (!(*count_it)->isSquashed() && !(*count_it)->isSquashedInIQ()) {
if (!(*count_it)->isIssued()) {
++total_insts;
} else if ((*count_it)->isMemRef() &&
!(*count_it)->memOpDone) {
// Loads that have not been marked as executed still count
// towards the total instructions.
++total_insts;
}
}
++count_it;
}
}
return total_insts;
#else
return numEntries - freeEntries;
#endif
}
template <class Impl>
void
InstructionQueue<Impl>::dumpLists()
{
for (int i = 0; i < Num_OpClasses; ++i) {
cprintf("Ready list %i size: %i\n", i, readyInsts[i].size());
cprintf("\n");
}
cprintf("Non speculative list size: %i\n", nonSpecInsts.size());
NonSpecMapIt non_spec_it = nonSpecInsts.begin();
NonSpecMapIt non_spec_end_it = nonSpecInsts.end();
cprintf("Non speculative list: ");
while (non_spec_it != non_spec_end_it) {
cprintf("%#x [sn:%lli]", (*non_spec_it).second->readPC(),
(*non_spec_it).second->seqNum);
++non_spec_it;
}
cprintf("\n");
ListOrderIt list_order_it = listOrder.begin();
ListOrderIt list_order_end_it = listOrder.end();
int i = 1;
cprintf("List order: ");
while (list_order_it != list_order_end_it) {
cprintf("%i OpClass:%i [sn:%lli] ", i, (*list_order_it).queueType,
(*list_order_it).oldestInst);
++list_order_it;
++i;
}
cprintf("\n");
}
template <class Impl>
void
InstructionQueue<Impl>::dumpInsts()
{
for (int i = 0; i < numThreads; ++i) {
int num = 0;
int valid_num = 0;
ListIt inst_list_it = instList[i].begin();
while (inst_list_it != instList[i].end())
{
cprintf("Instruction:%i\n",
num);
if (!(*inst_list_it)->isSquashed()) {
if (!(*inst_list_it)->isIssued()) {
++valid_num;
cprintf("Count:%i\n", valid_num);
} else if ((*inst_list_it)->isMemRef() &&
!(*inst_list_it)->memOpDone) {
// Loads that have not been marked as executed
// still count towards the total instructions.
++valid_num;
cprintf("Count:%i\n", valid_num);
}
}
cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n"
"Issued:%i\nSquashed:%i\n",
(*inst_list_it)->readPC(),
(*inst_list_it)->seqNum,
(*inst_list_it)->threadNumber,
(*inst_list_it)->isIssued(),
(*inst_list_it)->isSquashed());
if ((*inst_list_it)->isMemRef()) {
cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
}
cprintf("\n");
inst_list_it++;
++num;
}
}
cprintf("Insts to Execute list:\n");
int num = 0;
int valid_num = 0;
ListIt inst_list_it = instsToExecute.begin();
while (inst_list_it != instsToExecute.end())
{
cprintf("Instruction:%i\n",
num);
if (!(*inst_list_it)->isSquashed()) {
if (!(*inst_list_it)->isIssued()) {
++valid_num;
cprintf("Count:%i\n", valid_num);
} else if ((*inst_list_it)->isMemRef() &&
!(*inst_list_it)->memOpDone) {
// Loads that have not been marked as executed
// still count towards the total instructions.
++valid_num;
cprintf("Count:%i\n", valid_num);
}
}
cprintf("PC:%#x\n[sn:%lli]\n[tid:%i]\n"
"Issued:%i\nSquashed:%i\n",
(*inst_list_it)->readPC(),
(*inst_list_it)->seqNum,
(*inst_list_it)->threadNumber,
(*inst_list_it)->isIssued(),
(*inst_list_it)->isSquashed());
if ((*inst_list_it)->isMemRef()) {
cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
}
cprintf("\n");
inst_list_it++;
++num;
}
}