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Feature arya dependency graph caching 3 #2

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a3caf8d
almost cached version
enqueueDequeue Feb 27, 2024
a3cd2c1
almost the cached version of depGraphs
enqueueDequeue Mar 5, 2024
41cd115
add not working cache returning code
enqueueDequeue Mar 5, 2024
5d58ef3
Using the cached dep graph and working!
enqueueDequeue Mar 5, 2024
69f2700
Add stats
enqueueDequeue Mar 28, 2024
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185 changes: 165 additions & 20 deletions src/cpu/o3/inst_queue.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -68,12 +68,23 @@ const RefCountingPtr<DynInst> invalid_inst;
class LookupCache {
public:
std::vector<bool> regScoreBoard;
std::vector<DynInstPtr> srcInsts;
DependencyGraph<DynInstPtr> depGraph;

LookupCache() {}

LookupCache(std::vector<bool> regScoreBoard,
std::vector<DynInstPtr> srcInsts,
DependencyGraph<DynInstPtr> depGraph): regScoreBoard(regScoreBoard), srcInsts(srcInsts), depGraph(depGraph) {}
DependencyGraph<DynInstPtr> depGraph): regScoreBoard(regScoreBoard), depGraph(depGraph) {}

LookupCache(const LookupCache &other): regScoreBoard(other.regScoreBoard), depGraph(other.depGraph) {}

LookupCache(LookupCache &&other): regScoreBoard(std::move(other.regScoreBoard)), depGraph(std::move(other.depGraph)) {}

LookupCache &operator=(const LookupCache &other) {
this->regScoreBoard = other.regScoreBoard;
this->depGraph = other.depGraph;

return *this;
}
};

InstructionQueue::FUCompletion::FUCompletion(const DynInstPtr &_inst,
Expand Down Expand Up @@ -108,7 +119,7 @@ InstructionQueue::InstructionQueue(CPU *cpu_ptr, IEW *iew_ptr,
totalWidth(params.issueWidth),
commitToIEWDelay(params.commitToIEWDelay),
iqStats(cpu, totalWidth),
iqIOStats(cpu)
iqIOStats(cpu, totalWidth)
{
assert(fuPool);

Expand Down Expand Up @@ -338,7 +349,7 @@ InstructionQueue::IQStats::IQStats(CPU *cpu, const unsigned &total_width)
fuBusyRate = fuBusy / instsIssued;
}

InstructionQueue::IQIOStats::IQIOStats(statistics::Group *parent)
InstructionQueue::IQIOStats::IQIOStats(statistics::Group *parent, const unsigned total_width)
: statistics::Group(parent),
ADD_STAT(intInstQueueReads, statistics::units::Count::get(),
"Number of integer instruction queue reads"),
Expand All @@ -363,7 +374,13 @@ InstructionQueue::IQIOStats::IQIOStats(statistics::Group *parent)
ADD_STAT(fpAluAccesses, statistics::units::Count::get(),
"Number of floating point alu accesses"),
ADD_STAT(vecAluAccesses, statistics::units::Count::get(),
"Number of vector alu accesses")
"Number of vector alu accesses"),
ADD_STAT(chainsOfLength, statistics::units::Count::get(),
"How many chains of a given length"),
ADD_STAT(chainReuse, statistics::units::Count::get(),
"Number of times each chain of the given length is reused"),
ADD_STAT(numChains, statistics::units::Count::get(),
"Number of Chains in the cache")
{
using namespace statistics;
intInstQueueReads
Expand Down Expand Up @@ -401,6 +418,18 @@ InstructionQueue::IQIOStats::IQIOStats(statistics::Group *parent)

vecAluAccesses
.flags(total);

chainsOfLength
.init(total_width + 1)
.flags(total);

chainReuse
.init(total_width + 1)
.flags(pdf | dist);

for (int i = 0; i <= total_width; i++) {
chainReuse.subname(i, "reuse_" + std::to_string(i));
}
}

void
Expand Down Expand Up @@ -620,26 +649,53 @@ void printDepGraph(DependencyGraph<DynInstPtr> &depGraph) {

#include <unordered_map>

LookupCache
InstructionQueue::getDepGraphForInsts(std::list<DynInstPtr> instructions, int len) {
DynInstPtr findInstPtr(std::list<DynInstPtr> &instructions, DynInstPtr &refInst, int more);

LookupCache &
InstructionQueue::getDepGraphForInsts(std::list<DynInstPtr> &instructions, int len) {
int idx = 0;
std::string keyConcatenated;

for (DynInstPtr &new_inst : instructions) {
if (len == idx) {
break;
}

idx++;

const PCStateBase &pc = new_inst->pcState();
const std::string key(std::to_string(pc.instAddr()) + ":" + std::to_string(pc.microPC()));

keyConcatenated = keyConcatenated + "," + key;
}

DPRINTF(IQ, "searching for %s\n", keyConcatenated);

if (len != 0) {
if (0 != dependencyGraphCache.count(keyConcatenated)) {
// update the usage thingy

iqIOStats.chainReuse[len]++;

DPRINTF(IQ, "returning the existing dependency graph\n");
return dependencyGraphCache[keyConcatenated];
}
}

std::vector<bool> regScoreboardInternal;
std::vector<DynInstPtr> srcInstsInternal;
DependencyGraph<DynInstPtr> dependGraphInternal;

std::unordered_map<std::string, int> pcCounter;

regScoreboardInternal.resize(numPhysRegs);
srcInstsInternal.resize(numPhysRegs);
dependGraphInternal.resize(numPhysRegs);
dependGraphInternal.reset();

for (int i = 0; i < numPhysRegs; ++i) {
regScoreboard.push_back(true);
srcInstsInternal.push_back(invalid_inst);
}

int idx = 0;
idx = 0;

for (DynInstPtr &new_inst : instructions) {
int more = 0;
Expand Down Expand Up @@ -713,12 +769,8 @@ InstructionQueue::getDepGraphForInsts(std::list<DynInstPtr> instructions, int le
dest_reg->flatIndex(), new_inst->seqNum);
}

// this is not actually used
dependGraphInternal.setInst(dest_reg->flatIndex(), new_inst);

// this is actually used
srcInstsInternal[dest_reg->flatIndex()] = new_inst;

regScoreboardInternal[dest_reg->flatIndex()] = false;
}
}
Expand All @@ -735,7 +787,96 @@ InstructionQueue::getDepGraphForInsts(std::list<DynInstPtr> instructions, int le
DPRINTF(IQ, "not printing the graph, size = 0\n");
}

return LookupCache(regScoreboardInternal, srcInstsInternal, dependGraphInternal);
DPRINTF(IQ, "Assigning new Lookup Cache\n");

dependencyGraphCache.insert_or_assign(keyConcatenated, LookupCache(regScoreboardInternal, dependGraphInternal));

iqIOStats.chainsOfLength[len]++;
iqIOStats.numChains = dependencyGraphCache.size();

return dependencyGraphCache[keyConcatenated];
}

LookupCache
InstructionQueue::getDepGraphFromDepGraph(std::list<DynInstPtr> &instructions, LookupCache &cache) {
DependencyGraph<DynInstPtr> newDependGraphInternal;

newDependGraphInternal.resize(numPhysRegs);
newDependGraphInternal.reset();

DPRINTF(IQ, "depFromDep: Working on Producers\n");

for (int index = 0; index < numPhysRegs; index++) {
DependencyEntry<DynInstPtr> *instEntry = &cache.depGraph.dependGraph[index];

if (instEntry->inst != NULL) {
DynInstPtr actualInst = findInstPtr(instructions, instEntry->inst, instEntry->more);

// for MIPS like systems with one dest, this can be hardcoded to one
assert(1 == actualInst->numDestRegs());

int target_index = actualInst->renamedDestIdx(0)->flatIndex();

DPRINTF(IQ, "depFromDep: index: %i target_index: %i\n", index, target_index);

// set the producers
newDependGraphInternal.setInst(target_index, actualInst);
}
}

DPRINTF(IQ, "depFromDep: Working on Consumers\n");

for (int index = 0; index < numPhysRegs; index++) {
if (!cache.depGraph.empty(index)) {
DependencyEntry<DynInstPtr> *instEntry = &cache.depGraph.dependGraph[index];

// move to the consumers
instEntry = instEntry->next;

int target_index = -1;

while (nullptr != instEntry) {
DPRINTF(IQ, "depFromDep: finding %s / %llu, %i\n", instEntry->inst->pcState(), instEntry->inst->pcState().instAddr(), instEntry->more);

DynInstPtr newInst = findInstPtr(instructions, instEntry->inst, instEntry->more);

assert (NULL != newInst);

for (int t = 0; t < instEntry->inst->numSrcs(); t++) {
if (index == instEntry->inst->renamedSrcIdx(t)->flatIndex()) {
int tmp = newInst->renamedSrcIdx(t)->flatIndex();

if ((-1 == target_index) || (target_index == tmp)) {
// all ok
} else {
DPRINTF(IQ, "target_index: %i, tmp: %i\n", target_index, tmp);
assert (false);
}
target_index = tmp;
}
}

assert(-1 != target_index);

DPRINTF(IQ, "depFromDep instEntry: %llu (%s), newEntry: %llu (%s), phyReg: %i, targetPhyReg: %i\n",
instEntry->inst->seqNum, instEntry->inst->pcState(),
newInst->seqNum, newInst->pcState(),
index, target_index);

// create the new dep graph
DependencyEntry<DynInstPtr> entry;

entry.inst = newInst;
entry.more = instEntry->more;

newDependGraphInternal.insert(target_index, entry.inst, entry.more);

instEntry = instEntry->next;
}
}
}

return LookupCache(cache.regScoreBoard, newDependGraphInternal);
}

DynInstPtr findInstPtr(std::list<DynInstPtr> &instructions, DynInstPtr &refInst, int more) {
Expand All @@ -744,7 +885,8 @@ DynInstPtr findInstPtr(std::list<DynInstPtr> &instructions, DynInstPtr &refInst,
int currentCount = 0;

for (DynInstPtr &instruction : instructions) {
if (instruction->pcState() == refInst->pcState()) {
if (instruction->pcState().instAddr() == refInst->pcState().instAddr() &&
instruction->pcState().microPC() == refInst->pcState().microPC()) {
if (currentCount == more) {
return instruction;
}
Expand Down Expand Up @@ -784,7 +926,9 @@ InstructionQueue::finalizeInsertForCycle()
DPRINTF(IQ, "finalize begin, queue size: %i\n", (int) temporaryInstInsertQueue.size());

int queueableInstructionsSize = temporaryInstInsertQueue.size(); // std::min((unsigned) temporaryInstInsertQueue.size(), freeEntries);
LookupCache newDepGraph = getDepGraphForInsts(temporaryInstInsertQueue, queueableInstructionsSize);
LookupCache &cacheDepGraph = getDepGraphForInsts(temporaryInstInsertQueue, queueableInstructionsSize);
LookupCache newDepGraph = getDepGraphFromDepGraph(temporaryInstInsertQueue, cacheDepGraph);
// LookupCache newDepGraph = cacheDepGraph;

for (const auto &new_inst : temporaryInstInsertQueue) {
instList[new_inst->threadNumber].push_back(new_inst);
Expand Down Expand Up @@ -913,7 +1057,8 @@ InstructionQueue::finalizeInsertForCycle()
DPRINTF(IQ, "almost done\n");

if (0 != queueableInstructionsSize) {
printDepGraph(dependGraph);
DPRINTF(IQ, "not printing the actual dep graph\n");
// printDepGraph(dependGraph);
} else {
DPRINTF(IQ, "not printing the actual dep graph\n");
}
Expand Down
12 changes: 9 additions & 3 deletions src/cpu/o3/inst_queue.hh
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@

#include <list>
#include <map>
#include <unordered_map>
#include <queue>
#include <vector>

Expand Down Expand Up @@ -185,7 +186,8 @@ class InstructionQueue
/** Inserts a new instruction into the IQ. */
void insert(const DynInstPtr &new_inst);

LookupCache getDepGraphForInsts(std::list<DynInstPtr> instructions, int len);
LookupCache &getDepGraphForInsts(std::list<DynInstPtr> &instructions, int len);
LookupCache getDepGraphFromDepGraph(std::list<DynInstPtr> &instructions, LookupCache &cache);

void finalizeInsertForCycle();

Expand Down Expand Up @@ -344,7 +346,7 @@ class InstructionQueue
std::list<DynInstPtr> temporaryInstInsertQueue;

// todo: change the vector<long> to pc
std::map<std::vector<long>, LookupCache> dependencyGraphCache;
std::unordered_map<std::string, LookupCache> dependencyGraphCache;

/**
* Struct for comparing entries to be added to the priority queue.
Expand Down Expand Up @@ -556,7 +558,7 @@ class InstructionQueue
public:
struct IQIOStats : public statistics::Group
{
IQIOStats(statistics::Group *parent);
IQIOStats(statistics::Group *parent, const unsigned total_width);
statistics::Scalar intInstQueueReads;
statistics::Scalar intInstQueueWrites;
statistics::Scalar intInstQueueWakeupAccesses;
Expand All @@ -570,6 +572,10 @@ class InstructionQueue
statistics::Scalar intAluAccesses;
statistics::Scalar fpAluAccesses;
statistics::Scalar vecAluAccesses;

statistics::Vector chainsOfLength;
statistics::Vector chainReuse;
statistics::Scalar numChains;
} iqIOStats;
};

Expand Down