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gem5 / public / gem5 / b715c2d513f43c1b717dd62c30ee5b1bdbde079c / . / src / cpu / o3 / rename_impl.hh
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/*
* Copyright (c) 2010-2012, 2014-2019 ARM Limited
* Copyright (c) 2013 Advanced Micro Devices, Inc.
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2004-2006 The Regents of The University of Michigan
* All rights reserved.
*
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* 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;
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* 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
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* this software without specific prior written permission.
*
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/
#ifndef __CPU_O3_RENAME_IMPL_HH__
#define __CPU_O3_RENAME_IMPL_HH__
#include <list>
#include "arch/registers.hh"
#include "config/the_isa.hh"
#include "cpu/o3/rename.hh"
#include "cpu/reg_class.hh"
#include "debug/Activity.hh"
#include "debug/Rename.hh"
#include "debug/O3PipeView.hh"
#include "params/DerivO3CPU.hh"
using namespace std;
template <class Impl>
DefaultRename<Impl>::DefaultRename(O3CPU *_cpu, DerivO3CPUParams *params)
: cpu(_cpu),
iewToRenameDelay(params->iewToRenameDelay),
decodeToRenameDelay(params->decodeToRenameDelay),
commitToRenameDelay(params->commitToRenameDelay),
renameWidth(params->renameWidth),
commitWidth(params->commitWidth),
numThreads(params->numThreads),
stats(_cpu)
{
if (renameWidth > Impl::MaxWidth)
fatal("renameWidth (%d) is larger than compiled limit (%d),\n"
"\tincrease MaxWidth in src/cpu/o3/impl.hh\n",
renameWidth, static_cast<int>(Impl::MaxWidth));
// @todo: Make into a parameter.
skidBufferMax = (decodeToRenameDelay + 1) * params->decodeWidth;
for (uint32_t tid = 0; tid < Impl::MaxThreads; tid++) {
renameStatus[tid] = Idle;
renameMap[tid] = nullptr;
instsInProgress[tid] = 0;
loadsInProgress[tid] = 0;
storesInProgress[tid] = 0;
freeEntries[tid] = {0, 0, 0, 0};
emptyROB[tid] = true;
stalls[tid] = {false, false};
serializeInst[tid] = nullptr;
serializeOnNextInst[tid] = false;
}
}
template <class Impl>
std::string
DefaultRename<Impl>::name() const
{
return cpu->name() + ".rename";
}
template <class Impl>
DefaultRename<Impl>::RenameStats::RenameStats(Stats::Group *parent)
: Stats::Group(parent, "rename"),
ADD_STAT(squashCycles, "Number of cycles rename is squashing"),
ADD_STAT(idleCycles, "Number of cycles rename is idle"),
ADD_STAT(blockCycles, "Number of cycles rename is blocking"),
ADD_STAT(serializeStallCycles, "count of cycles rename stalled"
"for serializing inst"),
ADD_STAT(runCycles, "Number of cycles rename is running"),
ADD_STAT(unblockCycles, "Number of cycles rename is unblocking"),
ADD_STAT(renamedInsts, "Number of instructions processed by"
" rename"),
ADD_STAT(squashedInsts, "Number of squashed instructions"
" processed by rename"),
ADD_STAT(ROBFullEvents, "Number of times rename has blocked"
" due to ROB full"),
ADD_STAT(IQFullEvents, "Number of times rename has blocked due"
" to IQ full"),
ADD_STAT(LQFullEvents, "Number of times rename has blocked due"
" to LQ full" ),
ADD_STAT(SQFullEvents, "Number of times rename has blocked due"
" to SQ full"),
ADD_STAT(fullRegistersEvents, "Number of times there has been no"
" free registers"),
ADD_STAT(renamedOperands, "Number of destination operands rename"
" has renamed"),
ADD_STAT(lookups, "Number of register rename lookups that"
" rename has made"),
ADD_STAT(intLookups, "Number of integer rename lookups"),
ADD_STAT(fpLookups, "Number of floating rename lookups"),
ADD_STAT(vecLookups, "Number of vector rename lookups"),
ADD_STAT(vecPredLookups, "Number of vector predicate rename"
" lookups"),
ADD_STAT(committedMaps, "Number of HB maps that are committed"),
ADD_STAT(undoneMaps, "Number of HB maps that are undone due to"
" squashing"),
ADD_STAT(serializing, "count of serializing insts renamed" ),
ADD_STAT(tempSerializing, "count of temporary serializing insts"
" renamed"),
ADD_STAT(skidInsts, "count of insts added to the skid buffer")
{
squashCycles.prereq(squashCycles);
idleCycles.prereq(idleCycles);
blockCycles.prereq(blockCycles);
serializeStallCycles.flags(Stats::total);
runCycles.prereq(idleCycles);
unblockCycles.prereq(unblockCycles);
renamedInsts.prereq(renamedInsts);
squashedInsts.prereq(squashedInsts);
ROBFullEvents.prereq(ROBFullEvents);
IQFullEvents.prereq(IQFullEvents);
LQFullEvents.prereq(LQFullEvents);
SQFullEvents.prereq(SQFullEvents);
fullRegistersEvents.prereq(fullRegistersEvents);
renamedOperands.prereq(renamedOperands);
lookups.prereq(lookups);
intLookups.prereq(intLookups);
fpLookups.prereq(fpLookups);
vecLookups.prereq(vecLookups);
vecPredLookups.prereq(vecPredLookups);
committedMaps.prereq(committedMaps);
undoneMaps.prereq(undoneMaps);
serializing.flags(Stats::total);
tempSerializing.flags(Stats::total);
skidInsts.flags(Stats::total);
}
template <class Impl>
void
DefaultRename<Impl>::regProbePoints()
{
ppRename = new ProbePointArg<DynInstPtr>(cpu->getProbeManager(), "Rename");
ppSquashInRename = new ProbePointArg<SeqNumRegPair>(cpu->getProbeManager(),
"SquashInRename");
}
template <class Impl>
void
DefaultRename<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
{
timeBuffer = tb_ptr;
// Setup wire to read information from time buffer, from IEW stage.
fromIEW = timeBuffer->getWire(-iewToRenameDelay);
// Setup wire to read infromation from time buffer, from commit stage.
fromCommit = timeBuffer->getWire(-commitToRenameDelay);
// Setup wire to write information to previous stages.
toDecode = timeBuffer->getWire(0);
}
template <class Impl>
void
DefaultRename<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr)
{
renameQueue = rq_ptr;
// Setup wire to write information to future stages.
toIEW = renameQueue->getWire(0);
}
template <class Impl>
void
DefaultRename<Impl>::setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr)
{
decodeQueue = dq_ptr;
// Setup wire to get information from decode.
fromDecode = decodeQueue->getWire(-decodeToRenameDelay);
}
template <class Impl>
void
DefaultRename<Impl>::startupStage()
{
resetStage();
}
template <class Impl>
void
DefaultRename<Impl>::clearStates(ThreadID tid)
{
renameStatus[tid] = Idle;
freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
freeEntries[tid].lqEntries = iew_ptr->ldstQueue.numFreeLoadEntries(tid);
freeEntries[tid].sqEntries = iew_ptr->ldstQueue.numFreeStoreEntries(tid);
freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
emptyROB[tid] = true;
stalls[tid].iew = false;
serializeInst[tid] = NULL;
instsInProgress[tid] = 0;
loadsInProgress[tid] = 0;
storesInProgress[tid] = 0;
serializeOnNextInst[tid] = false;
}
template <class Impl>
void
DefaultRename<Impl>::resetStage()
{
_status = Inactive;
resumeSerialize = false;
resumeUnblocking = false;
// Grab the number of free entries directly from the stages.
for (ThreadID tid = 0; tid < numThreads; tid++) {
renameStatus[tid] = Idle;
freeEntries[tid].iqEntries = iew_ptr->instQueue.numFreeEntries(tid);
freeEntries[tid].lqEntries = iew_ptr->ldstQueue.numFreeLoadEntries(tid);
freeEntries[tid].sqEntries = iew_ptr->ldstQueue.numFreeStoreEntries(tid);
freeEntries[tid].robEntries = commit_ptr->numROBFreeEntries(tid);
emptyROB[tid] = true;
stalls[tid].iew = false;
serializeInst[tid] = NULL;
instsInProgress[tid] = 0;
loadsInProgress[tid] = 0;
storesInProgress[tid] = 0;
serializeOnNextInst[tid] = false;
}
}
template<class Impl>
void
DefaultRename<Impl>::setActiveThreads(list<ThreadID> *at_ptr)
{
activeThreads = at_ptr;
}
template <class Impl>
void
DefaultRename<Impl>::setRenameMap(RenameMap rm_ptr[])
{
for (ThreadID tid = 0; tid < numThreads; tid++)
renameMap[tid] = &rm_ptr[tid];
}
template <class Impl>
void
DefaultRename<Impl>::setFreeList(FreeList *fl_ptr)
{
freeList = fl_ptr;
}
template<class Impl>
void
DefaultRename<Impl>::setScoreboard(Scoreboard *_scoreboard)
{
scoreboard = _scoreboard;
}
template <class Impl>
bool
DefaultRename<Impl>::isDrained() const
{
for (ThreadID tid = 0; tid < numThreads; tid++) {
if (instsInProgress[tid] != 0 ||
!historyBuffer[tid].empty() ||
!skidBuffer[tid].empty() ||
!insts[tid].empty() ||
(renameStatus[tid] != Idle && renameStatus[tid] != Running))
return false;
}
return true;
}
template <class Impl>
void
DefaultRename<Impl>::takeOverFrom()
{
resetStage();
}
template <class Impl>
void
DefaultRename<Impl>::drainSanityCheck() const
{
for (ThreadID tid = 0; tid < numThreads; tid++) {
assert(historyBuffer[tid].empty());
assert(insts[tid].empty());
assert(skidBuffer[tid].empty());
assert(instsInProgress[tid] == 0);
}
}
template <class Impl>
void
DefaultRename<Impl>::squash(const InstSeqNum &squash_seq_num, ThreadID tid)
{
DPRINTF(Rename, "[tid:%i] [squash sn:%llu] Squashing instructions.\n",
tid,squash_seq_num);
// Clear the stall signal if rename was blocked or unblocking before.
// If it still needs to block, the blocking should happen the next
// cycle and there should be space to hold everything due to the squash.
if (renameStatus[tid] == Blocked ||
renameStatus[tid] == Unblocking) {
toDecode->renameUnblock[tid] = 1;
resumeSerialize = false;
serializeInst[tid] = NULL;
} else if (renameStatus[tid] == SerializeStall) {
if (serializeInst[tid]->seqNum <= squash_seq_num) {
DPRINTF(Rename, "[tid:%i] [squash sn:%llu] "
"Rename will resume serializing after squash\n",
tid,squash_seq_num);
resumeSerialize = true;
assert(serializeInst[tid]);
} else {
resumeSerialize = false;
toDecode->renameUnblock[tid] = 1;
serializeInst[tid] = NULL;
}
}
// Set the status to Squashing.
renameStatus[tid] = Squashing;
// Squash any instructions from decode.
for (int i=0; i<fromDecode->size; i++) {
if (fromDecode->insts[i]->threadNumber == tid &&
fromDecode->insts[i]->seqNum > squash_seq_num) {
fromDecode->insts[i]->setSquashed();
wroteToTimeBuffer = true;
}
}
// Clear the instruction list and skid buffer in case they have any
// insts in them.
insts[tid].clear();
// Clear the skid buffer in case it has any data in it.
skidBuffer[tid].clear();
doSquash(squash_seq_num, tid);
}
template <class Impl>
void
DefaultRename<Impl>::tick()
{
wroteToTimeBuffer = false;
blockThisCycle = false;
bool status_change = false;
toIEWIndex = 0;
sortInsts();
list<ThreadID>::iterator threads = activeThreads->begin();
list<ThreadID>::iterator end = activeThreads->end();
// Check stall and squash signals.
while (threads != end) {
ThreadID tid = *threads++;
DPRINTF(Rename, "Processing [tid:%i]\n", tid);
status_change = checkSignalsAndUpdate(tid) || status_change;
rename(status_change, tid);
}
if (status_change) {
updateStatus();
}
if (wroteToTimeBuffer) {
DPRINTF(Activity, "Activity this cycle.\n");
cpu->activityThisCycle();
}
threads = activeThreads->begin();
while (threads != end) {
ThreadID tid = *threads++;
// If we committed this cycle then doneSeqNum will be > 0
if (fromCommit->commitInfo[tid].doneSeqNum != 0 &&
!fromCommit->commitInfo[tid].squash &&
renameStatus[tid] != Squashing) {
removeFromHistory(fromCommit->commitInfo[tid].doneSeqNum,
tid);
}
}
// @todo: make into updateProgress function
for (ThreadID tid = 0; tid < numThreads; tid++) {
instsInProgress[tid] -= fromIEW->iewInfo[tid].dispatched;
loadsInProgress[tid] -= fromIEW->iewInfo[tid].dispatchedToLQ;
storesInProgress[tid] -= fromIEW->iewInfo[tid].dispatchedToSQ;
assert(loadsInProgress[tid] >= 0);
assert(storesInProgress[tid] >= 0);
assert(instsInProgress[tid] >=0);
}
}
template<class Impl>
void
DefaultRename<Impl>::rename(bool &status_change, ThreadID tid)
{
// If status is Running or idle,
// call renameInsts()
// If status is Unblocking,
// buffer any instructions coming from decode
// continue trying to empty skid buffer
// check if stall conditions have passed
if (renameStatus[tid] == Blocked) {
++stats.blockCycles;
} else if (renameStatus[tid] == Squashing) {
++stats.squashCycles;
} else if (renameStatus[tid] == SerializeStall) {
++stats.serializeStallCycles;
// If we are currently in SerializeStall and resumeSerialize
// was set, then that means that we are resuming serializing
// this cycle. Tell the previous stages to block.
if (resumeSerialize) {
resumeSerialize = false;
block(tid);
toDecode->renameUnblock[tid] = false;
}
} else if (renameStatus[tid] == Unblocking) {
if (resumeUnblocking) {
block(tid);
resumeUnblocking = false;
toDecode->renameUnblock[tid] = false;
}
}
if (renameStatus[tid] == Running ||
renameStatus[tid] == Idle) {
DPRINTF(Rename,
"[tid:%i] "
"Not blocked, so attempting to run stage.\n",
tid);
renameInsts(tid);
} else if (renameStatus[tid] == Unblocking) {
renameInsts(tid);
if (validInsts()) {
// Add the current inputs to the skid buffer so they can be
// reprocessed when this stage unblocks.
skidInsert(tid);
}
// If we switched over to blocking, then there's a potential for
// an overall status change.
status_change = unblock(tid) || status_change || blockThisCycle;
}
}
template <class Impl>
void
DefaultRename<Impl>::renameInsts(ThreadID tid)
{
// Instructions can be either in the skid buffer or the queue of
// instructions coming from decode, depending on the status.
int insts_available = renameStatus[tid] == Unblocking ?
skidBuffer[tid].size() : insts[tid].size();
// Check the decode queue to see if instructions are available.
// If there are no available instructions to rename, then do nothing.
if (insts_available == 0) {
DPRINTF(Rename, "[tid:%i] Nothing to do, breaking out early.\n",
tid);
// Should I change status to idle?
++stats.idleCycles;
return;
} else if (renameStatus[tid] == Unblocking) {
++stats.unblockCycles;
} else if (renameStatus[tid] == Running) {
++stats.runCycles;
}
// Will have to do a different calculation for the number of free
// entries.
int free_rob_entries = calcFreeROBEntries(tid);
int free_iq_entries = calcFreeIQEntries(tid);
int min_free_entries = free_rob_entries;
FullSource source = ROB;
if (free_iq_entries < min_free_entries) {
min_free_entries = free_iq_entries;
source = IQ;
}
// Check if there's any space left.
if (min_free_entries <= 0) {
DPRINTF(Rename,
"[tid:%i] Blocking due to no free ROB/IQ/ entries.\n"
"ROB has %i free entries.\n"
"IQ has %i free entries.\n",
tid, free_rob_entries, free_iq_entries);
blockThisCycle = true;
block(tid);
incrFullStat(source);
return;
} else if (min_free_entries < insts_available) {
DPRINTF(Rename,
"[tid:%i] "
"Will have to block this cycle. "
"%i insts available, "
"but only %i insts can be renamed due to ROB/IQ/LSQ limits.\n",
tid, insts_available, min_free_entries);
insts_available = min_free_entries;
blockThisCycle = true;
incrFullStat(source);
}
InstQueue &insts_to_rename = renameStatus[tid] == Unblocking ?
skidBuffer[tid] : insts[tid];
DPRINTF(Rename,
"[tid:%i] "
"%i available instructions to send iew.\n",
tid, insts_available);
DPRINTF(Rename,
"[tid:%i] "
"%i insts pipelining from Rename | "
"%i insts dispatched to IQ last cycle.\n",
tid, instsInProgress[tid], fromIEW->iewInfo[tid].dispatched);
// Handle serializing the next instruction if necessary.
if (serializeOnNextInst[tid]) {
if (emptyROB[tid] && instsInProgress[tid] == 0) {
// ROB already empty; no need to serialize.
serializeOnNextInst[tid] = false;
} else if (!insts_to_rename.empty()) {
insts_to_rename.front()->setSerializeBefore();
}
}
int renamed_insts = 0;
while (insts_available > 0 && toIEWIndex < renameWidth) {
DPRINTF(Rename, "[tid:%i] Sending instructions to IEW.\n", tid);
assert(!insts_to_rename.empty());
DynInstPtr inst = insts_to_rename.front();
//For all kind of instructions, check ROB and IQ first
//For load instruction, check LQ size and take into account the inflight loads
//For store instruction, check SQ size and take into account the inflight stores
if (inst->isLoad()) {
if (calcFreeLQEntries(tid) <= 0) {
DPRINTF(Rename, "[tid:%i] Cannot rename due to no free LQ\n");
source = LQ;
incrFullStat(source);
break;
}
}
if (inst->isStore() || inst->isAtomic()) {
if (calcFreeSQEntries(tid) <= 0) {
DPRINTF(Rename, "[tid:%i] Cannot rename due to no free SQ\n");
source = SQ;
incrFullStat(source);
break;
}
}
insts_to_rename.pop_front();
if (renameStatus[tid] == Unblocking) {
DPRINTF(Rename,
"[tid:%i] "
"Removing [sn:%llu] PC:%s from rename skidBuffer\n",
tid, inst->seqNum, inst->pcState());
}
if (inst->isSquashed()) {
DPRINTF(Rename,
"[tid:%i] "
"instruction %i with PC %s is squashed, skipping.\n",
tid, inst->seqNum, inst->pcState());
++stats.squashedInsts;
// Decrement how many instructions are available.
--insts_available;
continue;
}
DPRINTF(Rename,
"[tid:%i] "
"Processing instruction [sn:%llu] with PC %s.\n",
tid, inst->seqNum, inst->pcState());
// Check here to make sure there are enough destination registers
// to rename to. Otherwise block.
if (!renameMap[tid]->canRename(inst->numIntDestRegs(),
inst->numFPDestRegs(),
inst->numVecDestRegs(),
inst->numVecElemDestRegs(),
inst->numVecPredDestRegs(),
inst->numCCDestRegs())) {
DPRINTF(Rename,
"Blocking due to "
" lack of free physical registers to rename to.\n");
blockThisCycle = true;
insts_to_rename.push_front(inst);
++stats.fullRegistersEvents;
break;
}
// Handle serializeAfter/serializeBefore instructions.
// serializeAfter marks the next instruction as serializeBefore.
// serializeBefore makes the instruction wait in rename until the ROB
// is empty.
// In this model, IPR accesses are serialize before
// instructions, and store conditionals are serialize after
// instructions. This is mainly due to lack of support for
// out-of-order operations of either of those classes of
// instructions.
if ((inst->isIprAccess() || inst->isSerializeBefore()) &&
!inst->isSerializeHandled()) {
DPRINTF(Rename, "Serialize before instruction encountered.\n");
if (!inst->isTempSerializeBefore()) {
stats.serializing++;
inst->setSerializeHandled();
} else {
stats.tempSerializing++;
}
// Change status over to SerializeStall so that other stages know
// what this is blocked on.
renameStatus[tid] = SerializeStall;
serializeInst[tid] = inst;
blockThisCycle = true;
break;
} else if ((inst->isStoreConditional() || inst->isSerializeAfter()) &&
!inst->isSerializeHandled()) {
DPRINTF(Rename, "Serialize after instruction encountered.\n");
stats.serializing++;
inst->setSerializeHandled();
serializeAfter(insts_to_rename, tid);
}
renameSrcRegs(inst, inst->threadNumber);
renameDestRegs(inst, inst->threadNumber);
if (inst->isAtomic() || inst->isStore()) {
storesInProgress[tid]++;
} else if (inst->isLoad()) {
loadsInProgress[tid]++;
}
++renamed_insts;
// Notify potential listeners that source and destination registers for
// this instruction have been renamed.
ppRename->notify(inst);
// Put instruction in rename queue.
toIEW->insts[toIEWIndex] = inst;
++(toIEW->size);
// Increment which instruction we're on.
++toIEWIndex;
// Decrement how many instructions are available.
--insts_available;
}
instsInProgress[tid] += renamed_insts;
stats.renamedInsts += renamed_insts;
// If we wrote to the time buffer, record this.
if (toIEWIndex) {
wroteToTimeBuffer = true;
}
// Check if there's any instructions left that haven't yet been renamed.
// If so then block.
if (insts_available) {
blockThisCycle = true;
}
if (blockThisCycle) {
block(tid);
toDecode->renameUnblock[tid] = false;
}
}
template<class Impl>
void
DefaultRename<Impl>::skidInsert(ThreadID tid)
{
DynInstPtr inst = NULL;
while (!insts[tid].empty()) {
inst = insts[tid].front();
insts[tid].pop_front();
assert(tid == inst->threadNumber);
DPRINTF(Rename, "[tid:%i] Inserting [sn:%llu] PC: %s into Rename "
"skidBuffer\n", tid, inst->seqNum, inst->pcState());
++stats.skidInsts;
skidBuffer[tid].push_back(inst);
}
if (skidBuffer[tid].size() > skidBufferMax)
{
typename InstQueue::iterator it;
warn("Skidbuffer contents:\n");
for (it = skidBuffer[tid].begin(); it != skidBuffer[tid].end(); it++)
{
warn("[tid:%i] %s [sn:%llu].\n", tid,
(*it)->staticInst->disassemble(inst->instAddr()),
(*it)->seqNum);
}
panic("Skidbuffer Exceeded Max Size");
}
}
template <class Impl>
void
DefaultRename<Impl>::sortInsts()
{
int insts_from_decode = fromDecode->size;
for (int i = 0; i < insts_from_decode; ++i) {
const DynInstPtr &inst = fromDecode->insts[i];
insts[inst->threadNumber].push_back(inst);
#if TRACING_ON
if (DTRACE(O3PipeView)) {
inst->renameTick = curTick() - inst->fetchTick;
}
#endif
}
}
template<class Impl>
bool
DefaultRename<Impl>::skidsEmpty()
{
list<ThreadID>::iterator threads = activeThreads->begin();
list<ThreadID>::iterator end = activeThreads->end();
while (threads != end) {
ThreadID tid = *threads++;
if (!skidBuffer[tid].empty())
return false;
}
return true;
}
template<class Impl>
void
DefaultRename<Impl>::updateStatus()
{
bool any_unblocking = false;
list<ThreadID>::iterator threads = activeThreads->begin();
list<ThreadID>::iterator end = activeThreads->end();
while (threads != end) {
ThreadID tid = *threads++;
if (renameStatus[tid] == Unblocking) {
any_unblocking = true;
break;
}
}
// Rename will have activity if it's unblocking.
if (any_unblocking) {
if (_status == Inactive) {
_status = Active;
DPRINTF(Activity, "Activating stage.\n");
cpu->activateStage(O3CPU::RenameIdx);
}
} else {
// If it's not unblocking, then rename will not have any internal
// activity. Switch it to inactive.
if (_status == Active) {
_status = Inactive;
DPRINTF(Activity, "Deactivating stage.\n");
cpu->deactivateStage(O3CPU::RenameIdx);
}
}
}
template <class Impl>
bool
DefaultRename<Impl>::block(ThreadID tid)
{
DPRINTF(Rename, "[tid:%i] Blocking.\n", tid);
// Add the current inputs onto the skid buffer, so they can be
// reprocessed when this stage unblocks.
skidInsert(tid);
// Only signal backwards to block if the previous stages do not think
// rename is already blocked.
if (renameStatus[tid] != Blocked) {
// If resumeUnblocking is set, we unblocked during the squash,
// but now we're have unblocking status. We need to tell earlier
// stages to block.
if (resumeUnblocking || renameStatus[tid] != Unblocking) {
toDecode->renameBlock[tid] = true;
toDecode->renameUnblock[tid] = false;
wroteToTimeBuffer = true;
}
// Rename can not go from SerializeStall to Blocked, otherwise
// it would not know to complete the serialize stall.
if (renameStatus[tid] != SerializeStall) {
// Set status to Blocked.
renameStatus[tid] = Blocked;
return true;
}
}
return false;
}
template <class Impl>
bool
DefaultRename<Impl>::unblock(ThreadID tid)
{
DPRINTF(Rename, "[tid:%i] Trying to unblock.\n", tid);
// Rename is done unblocking if the skid buffer is empty.
if (skidBuffer[tid].empty() && renameStatus[tid] != SerializeStall) {
DPRINTF(Rename, "[tid:%i] Done unblocking.\n", tid);
toDecode->renameUnblock[tid] = true;
wroteToTimeBuffer = true;
renameStatus[tid] = Running;
return true;
}
return false;
}
template <class Impl>
void
DefaultRename<Impl>::doSquash(const InstSeqNum &squashed_seq_num, ThreadID tid)
{
typename std::list<RenameHistory>::iterator hb_it =
historyBuffer[tid].begin();
// After a syscall squashes everything, the history buffer may be empty
// but the ROB may still be squashing instructions.
// Go through the most recent instructions, undoing the mappings
// they did and freeing up the registers.
while (!historyBuffer[tid].empty() &&
hb_it->instSeqNum > squashed_seq_num) {
assert(hb_it != historyBuffer[tid].end());
DPRINTF(Rename, "[tid:%i] Removing history entry with sequence "
"number %i (archReg: %d, newPhysReg: %d, prevPhysReg: %d).\n",
tid, hb_it->instSeqNum, hb_it->archReg.index(),
hb_it->newPhysReg->index(), hb_it->prevPhysReg->index());
// Undo the rename mapping only if it was really a change.
// Special regs that are not really renamed (like misc regs
// and the zero reg) can be recognized because the new mapping
// is the same as the old one. While it would be merely a
// waste of time to update the rename table, we definitely
// don't want to put these on the free list.
if (hb_it->newPhysReg != hb_it->prevPhysReg) {
// Tell the rename map to set the architected register to the
// previous physical register that it was renamed to.
renameMap[tid]->setEntry(hb_it->archReg, hb_it->prevPhysReg);
// Put the renamed physical register back on the free list.
freeList->addReg(hb_it->newPhysReg);
}
// Notify potential listeners that the register mapping needs to be
// removed because the instruction it was mapped to got squashed. Note
// that this is done before hb_it is incremented.
ppSquashInRename->notify(std::make_pair(hb_it->instSeqNum,
hb_it->newPhysReg));
historyBuffer[tid].erase(hb_it++);
++stats.undoneMaps;
}
// Check if we need to change vector renaming mode after squashing
cpu->switchRenameMode(tid, freeList);
}
template<class Impl>
void
DefaultRename<Impl>::removeFromHistory(InstSeqNum inst_seq_num, ThreadID tid)
{
DPRINTF(Rename, "[tid:%i] Removing a committed instruction from the "
"history buffer %u (size=%i), until [sn:%llu].\n",
tid, tid, historyBuffer[tid].size(), inst_seq_num);
typename std::list<RenameHistory>::iterator hb_it =
historyBuffer[tid].end();
--hb_it;
if (historyBuffer[tid].empty()) {
DPRINTF(Rename, "[tid:%i] History buffer is empty.\n", tid);
return;
} else if (hb_it->instSeqNum > inst_seq_num) {
DPRINTF(Rename, "[tid:%i] [sn:%llu] "
"Old sequence number encountered. "
"Ensure that a syscall happened recently.\n",
tid,inst_seq_num);
return;
}
// Commit all the renames up until (and including) the committed sequence
// number. Some or even all of the committed instructions may not have
// rename histories if they did not have destination registers that were
// renamed.
while (!historyBuffer[tid].empty() &&
hb_it != historyBuffer[tid].end() &&
hb_it->instSeqNum <= inst_seq_num) {
DPRINTF(Rename, "[tid:%i] Freeing up older rename of reg %i (%s), "
"[sn:%llu].\n",
tid, hb_it->prevPhysReg->index(),
hb_it->prevPhysReg->className(),
hb_it->instSeqNum);
// Don't free special phys regs like misc and zero regs, which
// can be recognized because the new mapping is the same as
// the old one.
if (hb_it->newPhysReg != hb_it->prevPhysReg) {
freeList->addReg(hb_it->prevPhysReg);
}
++stats.committedMaps;
historyBuffer[tid].erase(hb_it--);
}
}
template <class Impl>
inline void
DefaultRename<Impl>::renameSrcRegs(const DynInstPtr &inst, ThreadID tid)
{
ThreadContext *tc = inst->tcBase();
RenameMap *map = renameMap[tid];
unsigned num_src_regs = inst->numSrcRegs();
// Get the architectual register numbers from the source and
// operands, and redirect them to the right physical register.
for (int src_idx = 0; src_idx < num_src_regs; src_idx++) {
const RegId& src_reg = inst->srcRegIdx(src_idx);
PhysRegIdPtr renamed_reg;
renamed_reg = map->lookup(tc->flattenRegId(src_reg));
switch (src_reg.classValue()) {
case IntRegClass:
stats.intLookups++;
break;
case FloatRegClass:
stats.fpLookups++;
break;
case VecRegClass:
case VecElemClass:
stats.vecLookups++;
break;
case VecPredRegClass:
stats.vecPredLookups++;
break;
case CCRegClass:
case MiscRegClass:
break;
default:
panic("Invalid register class: %d.", src_reg.classValue());
}
DPRINTF(Rename,
"[tid:%i] "
"Looking up %s arch reg %i, got phys reg %i (%s)\n",
tid, src_reg.className(),
src_reg.index(), renamed_reg->index(),
renamed_reg->className());
inst->renameSrcReg(src_idx, renamed_reg);
// See if the register is ready or not.
if (scoreboard->getReg(renamed_reg)) {
DPRINTF(Rename,
"[tid:%i] "
"Register %d (flat: %d) (%s) is ready.\n",
tid, renamed_reg->index(), renamed_reg->flatIndex(),
renamed_reg->className());
inst->markSrcRegReady(src_idx);
} else {
DPRINTF(Rename,
"[tid:%i] "
"Register %d (flat: %d) (%s) is not ready.\n",
tid, renamed_reg->index(), renamed_reg->flatIndex(),
renamed_reg->className());
}
++stats.lookups;
}
}
template <class Impl>
inline void
DefaultRename<Impl>::renameDestRegs(const DynInstPtr &inst, ThreadID tid)
{
ThreadContext *tc = inst->tcBase();
RenameMap *map = renameMap[tid];
unsigned num_dest_regs = inst->numDestRegs();
// Rename the destination registers.
for (int dest_idx = 0; dest_idx < num_dest_regs; dest_idx++) {
const RegId& dest_reg = inst->destRegIdx(dest_idx);
typename RenameMap::RenameInfo rename_result;
RegId flat_dest_regid = tc->flattenRegId(dest_reg);
flat_dest_regid.setNumPinnedWrites(dest_reg.getNumPinnedWrites());
rename_result = map->rename(flat_dest_regid);
inst->flattenDestReg(dest_idx, flat_dest_regid);
scoreboard->unsetReg(rename_result.first);
DPRINTF(Rename,
"[tid:%i] "
"Renaming arch reg %i (%s) to physical reg %i (%i).\n",
tid, dest_reg.index(), dest_reg.className(),
rename_result.first->index(),
rename_result.first->flatIndex());
// Record the rename information so that a history can be kept.
RenameHistory hb_entry(inst->seqNum, flat_dest_regid,
rename_result.first,
rename_result.second);
historyBuffer[tid].push_front(hb_entry);
DPRINTF(Rename, "[tid:%i] [sn:%llu] "
"Adding instruction to history buffer (size=%i).\n",
tid,(*historyBuffer[tid].begin()).instSeqNum,
historyBuffer[tid].size());
// Tell the instruction to rename the appropriate destination
// register (dest_idx) to the new physical register
// (rename_result.first), and record the previous physical
// register that the same logical register was renamed to
// (rename_result.second).
inst->renameDestReg(dest_idx,
rename_result.first,
rename_result.second);
++stats.renamedOperands;
}
}
template <class Impl>
inline int
DefaultRename<Impl>::calcFreeROBEntries(ThreadID tid)
{
int num_free = freeEntries[tid].robEntries -
(instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
//DPRINTF(Rename,"[tid:%i] %i rob free\n",tid,num_free);
return num_free;
}
template <class Impl>
inline int
DefaultRename<Impl>::calcFreeIQEntries(ThreadID tid)
{
int num_free = freeEntries[tid].iqEntries -
(instsInProgress[tid] - fromIEW->iewInfo[tid].dispatched);
//DPRINTF(Rename,"[tid:%i] %i iq free\n",tid,num_free);
return num_free;
}
template <class Impl>
inline int
DefaultRename<Impl>::calcFreeLQEntries(ThreadID tid)
{
int num_free = freeEntries[tid].lqEntries -
(loadsInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToLQ);
DPRINTF(Rename,
"calcFreeLQEntries: free lqEntries: %d, loadsInProgress: %d, "
"loads dispatchedToLQ: %d\n",
freeEntries[tid].lqEntries, loadsInProgress[tid],
fromIEW->iewInfo[tid].dispatchedToLQ);
return num_free;
}
template <class Impl>
inline int
DefaultRename<Impl>::calcFreeSQEntries(ThreadID tid)
{
int num_free = freeEntries[tid].sqEntries -
(storesInProgress[tid] - fromIEW->iewInfo[tid].dispatchedToSQ);
DPRINTF(Rename, "calcFreeSQEntries: free sqEntries: %d, storesInProgress: %d, "
"stores dispatchedToSQ: %d\n", freeEntries[tid].sqEntries,
storesInProgress[tid], fromIEW->iewInfo[tid].dispatchedToSQ);
return num_free;
}
template <class Impl>
unsigned
DefaultRename<Impl>::validInsts()
{
unsigned inst_count = 0;
for (int i=0; i<fromDecode->size; i++) {
if (!fromDecode->insts[i]->isSquashed())
inst_count++;
}
return inst_count;
}
template <class Impl>
void
DefaultRename<Impl>::readStallSignals(ThreadID tid)
{
if (fromIEW->iewBlock[tid]) {
stalls[tid].iew = true;
}
if (fromIEW->iewUnblock[tid]) {
assert(stalls[tid].iew);
stalls[tid].iew = false;
}
}
template <class Impl>
bool
DefaultRename<Impl>::checkStall(ThreadID tid)
{
bool ret_val = false;
if (stalls[tid].iew) {
DPRINTF(Rename,"[tid:%i] Stall from IEW stage detected.\n", tid);
ret_val = true;
} else if (calcFreeROBEntries(tid) <= 0) {
DPRINTF(Rename,"[tid:%i] Stall: ROB has 0 free entries.\n", tid);
ret_val = true;
} else if (calcFreeIQEntries(tid) <= 0) {
DPRINTF(Rename,"[tid:%i] Stall: IQ has 0 free entries.\n", tid);
ret_val = true;
} else if (calcFreeLQEntries(tid) <= 0 && calcFreeSQEntries(tid) <= 0) {
DPRINTF(Rename,"[tid:%i] Stall: LSQ has 0 free entries.\n", tid);
ret_val = true;
} else if (renameMap[tid]->numFreeEntries() <= 0) {
DPRINTF(Rename,"[tid:%i] Stall: RenameMap has 0 free entries.\n", tid);
ret_val = true;
} else if (renameStatus[tid] == SerializeStall &&
(!emptyROB[tid] || instsInProgress[tid])) {
DPRINTF(Rename,"[tid:%i] Stall: Serialize stall and ROB is not "
"empty.\n",
tid);
ret_val = true;
}
return ret_val;
}
template <class Impl>
void
DefaultRename<Impl>::readFreeEntries(ThreadID tid)
{
if (fromIEW->iewInfo[tid].usedIQ)
freeEntries[tid].iqEntries = fromIEW->iewInfo[tid].freeIQEntries;
if (fromIEW->iewInfo[tid].usedLSQ) {
freeEntries[tid].lqEntries = fromIEW->iewInfo[tid].freeLQEntries;
freeEntries[tid].sqEntries = fromIEW->iewInfo[tid].freeSQEntries;
}
if (fromCommit->commitInfo[tid].usedROB) {
freeEntries[tid].robEntries =
fromCommit->commitInfo[tid].freeROBEntries;
emptyROB[tid] = fromCommit->commitInfo[tid].emptyROB;
}
DPRINTF(Rename, "[tid:%i] Free IQ: %i, Free ROB: %i, "
"Free LQ: %i, Free SQ: %i, FreeRM %i(%i %i %i %i %i)\n",
tid,
freeEntries[tid].iqEntries,
freeEntries[tid].robEntries,
freeEntries[tid].lqEntries,
freeEntries[tid].sqEntries,
renameMap[tid]->numFreeEntries(),
renameMap[tid]->numFreeIntEntries(),
renameMap[tid]->numFreeFloatEntries(),
renameMap[tid]->numFreeVecEntries(),
renameMap[tid]->numFreePredEntries(),
renameMap[tid]->numFreeCCEntries());
DPRINTF(Rename, "[tid:%i] %i instructions not yet in ROB\n",
tid, instsInProgress[tid]);
}
template <class Impl>
bool
DefaultRename<Impl>::checkSignalsAndUpdate(ThreadID tid)
{
// Check if there's a squash signal, squash if there is
// Check stall signals, block if necessary.
// If status was blocked
// check if stall conditions have passed
// if so then go to unblocking
// If status was Squashing
// check if squashing is not high. Switch to running this cycle.
// If status was serialize stall
// check if ROB is empty and no insts are in flight to the ROB
readFreeEntries(tid);
readStallSignals(tid);
if (fromCommit->commitInfo[tid].squash) {
DPRINTF(Rename, "[tid:%i] Squashing instructions due to squash from "
"commit.\n", tid);
squash(fromCommit->commitInfo[tid].doneSeqNum, tid);
return true;
}
if (checkStall(tid)) {
return block(tid);
}
if (renameStatus[tid] == Blocked) {
DPRINTF(Rename, "[tid:%i] Done blocking, switching to unblocking.\n",
tid);
renameStatus[tid] = Unblocking;
unblock(tid);
return true;
}
if (renameStatus[tid] == Squashing) {
// Switch status to running if rename isn't being told to block or
// squash this cycle.
if (resumeSerialize) {
DPRINTF(Rename,
"[tid:%i] Done squashing, switching to serialize.\n", tid);
renameStatus[tid] = SerializeStall;
return true;
} else if (resumeUnblocking) {
DPRINTF(Rename,
"[tid:%i] Done squashing, switching to unblocking.\n",
tid);
renameStatus[tid] = Unblocking;
return true;
} else {
DPRINTF(Rename, "[tid:%i] Done squashing, switching to running.\n",
tid);
renameStatus[tid] = Running;
return false;
}
}
if (renameStatus[tid] == SerializeStall) {
// Stall ends once the ROB is free.
DPRINTF(Rename, "[tid:%i] Done with serialize stall, switching to "
"unblocking.\n", tid);
DynInstPtr serial_inst = serializeInst[tid];
renameStatus[tid] = Unblocking;
unblock(tid);
DPRINTF(Rename, "[tid:%i] Processing instruction [%lli] with "
"PC %s.\n", tid, serial_inst->seqNum, serial_inst->pcState());
// Put instruction into queue here.
serial_inst->clearSerializeBefore();
if (!skidBuffer[tid].empty()) {
skidBuffer[tid].push_front(serial_inst);
} else {
insts[tid].push_front(serial_inst);
}
DPRINTF(Rename, "[tid:%i] Instruction must be processed by rename."
" Adding to front of list.\n", tid);
serializeInst[tid] = NULL;
return true;
}
// If we've reached this point, we have not gotten any signals that
// cause rename to change its status. Rename remains the same as before.
return false;
}
template<class Impl>
void
DefaultRename<Impl>::serializeAfter(InstQueue &inst_list, ThreadID tid)
{
if (inst_list.empty()) {
// Mark a bit to say that I must serialize on the next instruction.
serializeOnNextInst[tid] = true;
return;
}
// Set the next instruction as serializing.
inst_list.front()->setSerializeBefore();
}
template <class Impl>
inline void
DefaultRename<Impl>::incrFullStat(const FullSource &source)
{
switch (source) {
case ROB:
++stats.ROBFullEvents;
break;
case IQ:
++stats.IQFullEvents;
break;
case LQ:
++stats.LQFullEvents;
break;
case SQ:
++stats.SQFullEvents;
break;
default:
panic("Rename full stall stat should be incremented for a reason!");
break;
}
}
template <class Impl>
void
DefaultRename<Impl>::dumpHistory()
{
typename std::list<RenameHistory>::iterator buf_it;
for (ThreadID tid = 0; tid < numThreads; tid++) {
buf_it = historyBuffer[tid].begin();
while (buf_it != historyBuffer[tid].end()) {
cprintf("Seq num: %i\nArch reg[%s]: %i New phys reg:"
" %i[%s] Old phys reg: %i[%s]\n",
(*buf_it).instSeqNum,
(*buf_it).archReg.className(),
(*buf_it).archReg.index(),
(*buf_it).newPhysReg->index(),
(*buf_it).newPhysReg->className(),
(*buf_it).prevPhysReg->index(),
(*buf_it).prevPhysReg->className());
buf_it++;
}
}
}
#endif//__CPU_O3_RENAME_IMPL_HH__