gem5/cpu/o3/rob_impl.hh
Kevin Lim cbfbb7bc56 Updates to bring CPU portion of m5 up-to-date with newmem.
--HG--
extra : convert_revision : 00e6eefb24e6ffd9c7c5d8165db26fbf6199fdc4
2006-08-02 12:05:34 -04:00

691 lines
16 KiB
C++

/*
* 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 "config/full_system.hh"
#include "cpu/o3/rob.hh"
using namespace std;
template <class Impl>
ROB<Impl>::ROB(unsigned _numEntries, unsigned _squashWidth,
string _smtROBPolicy, unsigned _smtROBThreshold,
unsigned _numThreads)
: numEntries(_numEntries),
squashWidth(_squashWidth),
numInstsInROB(0),
numThreads(_numThreads)
{
for (int tid=0; tid < numThreads; tid++) {
squashedSeqNum[tid] = 0;
doneSquashing[tid] = true;
threadEntries[tid] = 0;
}
string policy = _smtROBPolicy;
//Convert string to lowercase
std::transform(policy.begin(), policy.end(), policy.begin(),
(int(*)(int)) tolower);
//Figure out rob policy
if (policy == "dynamic") {
robPolicy = Dynamic;
//Set Max Entries to Total ROB Capacity
for (int i = 0; i < numThreads; i++) {
maxEntries[i]=numEntries;
}
} else if (policy == "partitioned") {
robPolicy = Partitioned;
DPRINTF(Fetch, "ROB sharing policy set to Partitioned\n");
//@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;
}
} else if (policy == "threshold") {
robPolicy = Threshold;
DPRINTF(Fetch, "ROB sharing policy set to Threshold\n");
int threshold = _smtROBThreshold;;
//Divide up by threshold amount
for (int i = 0; i < numThreads; i++) {
maxEntries[i]=threshold;
}
} else {
assert(0 && "Invalid ROB Sharing Policy.Options Are:{Dynamic,"
"Partitioned, Threshold}");
}
}
template <class Impl>
std::string
ROB<Impl>::name() const
{
return cpu->name() + ".rob";
}
template <class Impl>
void
ROB<Impl>::setCPU(FullCPU *cpu_ptr)
{
cpu = cpu_ptr;
// Set the per-thread iterators to the end of the instruction list.
for (int i=0; i < numThreads;i++) {
squashIt[i] = instList[i].end();
}
// Initialize the "universal" ROB head & tail point to invalid
// pointers
head = instList[0].end();
tail = instList[0].end();
}
template <class Impl>
void
ROB<Impl>::setActiveThreads(list<unsigned> *at_ptr)
{
DPRINTF(ROB, "Setting active threads list pointer.\n");
activeThreads = at_ptr;
}
template <class Impl>
void
ROB<Impl>::switchOut()
{
for (int tid = 0; tid < numThreads; tid++) {
instList[tid].clear();
}
}
template <class Impl>
void
ROB<Impl>::takeOverFrom()
{
for (int tid=0; tid < numThreads; tid++) {
doneSquashing[tid] = true;
threadEntries[tid] = 0;
squashIt[tid] = instList[tid].end();
}
numInstsInROB = 0;
// Initialize the "universal" ROB head & tail point to invalid
// pointers
head = instList[0].end();
tail = instList[0].end();
}
template <class Impl>
void
ROB<Impl>::resetEntries()
{
if (robPolicy != Dynamic || numThreads > 1) {
int active_threads = (*activeThreads).size();
list<unsigned>::iterator threads = (*activeThreads).begin();
list<unsigned>::iterator list_end = (*activeThreads).end();
while (threads != list_end) {
if (robPolicy == Partitioned) {
maxEntries[*threads++] = numEntries / active_threads;
} else if (robPolicy == Threshold && active_threads == 1) {
maxEntries[*threads++] = numEntries;
}
}
}
}
template <class Impl>
int
ROB<Impl>::entryAmount(int num_threads)
{
if (robPolicy == Partitioned) {
return numEntries / num_threads;
} else {
return 0;
}
}
template <class Impl>
int
ROB<Impl>::countInsts()
{
int total=0;
for (int i=0;i < numThreads;i++)
total += countInsts(i);
return total;
}
template <class Impl>
int
ROB<Impl>::countInsts(unsigned tid)
{
return instList[tid].size();
}
template <class Impl>
void
ROB<Impl>::insertInst(DynInstPtr &inst)
{
//assert(numInstsInROB == countInsts());
assert(inst);
DPRINTF(ROB, "Adding inst PC %#x to the ROB.\n", inst->readPC());
assert(numInstsInROB != numEntries);
int tid = inst->threadNumber;
instList[tid].push_back(inst);
//Set Up head iterator if this is the 1st instruction in the ROB
if (numInstsInROB == 0) {
head = instList[tid].begin();
assert((*head) == inst);
}
//Must Decrement for iterator to actually be valid since __.end()
//actually points to 1 after the last inst
tail = instList[tid].end();
tail--;
inst->setInROB();
++numInstsInROB;
++threadEntries[tid];
assert((*tail) == inst);
DPRINTF(ROB, "[tid:%i] Now has %d instructions.\n", tid, threadEntries[tid]);
}
// Whatever calls this function needs to ensure that it properly frees up
// registers prior to this function.
/*
template <class Impl>
void
ROB<Impl>::retireHead()
{
//assert(numInstsInROB == countInsts());
assert(numInstsInROB > 0);
int tid = (*head)->threadNumber;
retireHead(tid);
if (numInstsInROB == 0) {
tail = instList[tid].end();
}
}
*/
template <class Impl>
void
ROB<Impl>::retireHead(unsigned tid)
{
//assert(numInstsInROB == countInsts());
assert(numInstsInROB > 0);
// Get the head ROB instruction.
InstIt head_it = instList[tid].begin();
DynInstPtr head_inst = (*head_it);
assert(head_inst->readyToCommit());
DPRINTF(ROB, "[tid:%u]: Retiring head instruction, "
"instruction PC %#x,[sn:%lli]\n", tid, head_inst->readPC(),
head_inst->seqNum);
--numInstsInROB;
--threadEntries[tid];
head_inst->clearInROB();
head_inst->setCommitted();
instList[tid].erase(head_it);
//Update "Global" Head of ROB
updateHead();
// @todo: A special case is needed if the instruction being
// retired is the only instruction in the ROB; otherwise the tail
// iterator will become invalidated.
cpu->removeFrontInst(head_inst);
}
/*
template <class Impl>
bool
ROB<Impl>::isHeadReady()
{
if (numInstsInROB != 0) {
return (*head)->readyToCommit();
}
return false;
}
*/
template <class Impl>
bool
ROB<Impl>::isHeadReady(unsigned tid)
{
if (threadEntries[tid] != 0) {
return instList[tid].front()->readyToCommit();
}
return false;
}
template <class Impl>
bool
ROB<Impl>::canCommit()
{
//@todo: set ActiveThreads through ROB or CPU
list<unsigned>::iterator threads = (*activeThreads).begin();
while (threads != (*activeThreads).end()) {
unsigned tid = *threads++;
if (isHeadReady(tid)) {
return true;
}
}
return false;
}
template <class Impl>
unsigned
ROB<Impl>::numFreeEntries()
{
//assert(numInstsInROB == countInsts());
return numEntries - numInstsInROB;
}
template <class Impl>
unsigned
ROB<Impl>::numFreeEntries(unsigned tid)
{
return maxEntries[tid] - threadEntries[tid];
}
template <class Impl>
void
ROB<Impl>::doSquash(unsigned tid)
{
DPRINTF(ROB, "[tid:%u]: Squashing instructions until [sn:%i].\n",
tid, squashedSeqNum[tid]);
assert(squashIt[tid] != instList[tid].end());
if ((*squashIt[tid])->seqNum < squashedSeqNum[tid]) {
DPRINTF(ROB, "[tid:%u]: Done squashing instructions.\n",
tid);
squashIt[tid] = instList[tid].end();
doneSquashing[tid] = true;
return;
}
bool robTailUpdate = false;
for (int numSquashed = 0;
numSquashed < squashWidth &&
squashIt[tid] != instList[tid].end() &&
(*squashIt[tid])->seqNum > squashedSeqNum[tid];
++numSquashed)
{
DPRINTF(ROB, "[tid:%u]: Squashing instruction PC %#x, seq num %i.\n",
(*squashIt[tid])->threadNumber,
(*squashIt[tid])->readPC(),
(*squashIt[tid])->seqNum);
// Mark the instruction as squashed, and ready to commit so that
// it can drain out of the pipeline.
(*squashIt[tid])->setSquashed();
(*squashIt[tid])->setCanCommit();
if (squashIt[tid] == instList[tid].begin()) {
DPRINTF(ROB, "Reached head of instruction list while "
"squashing.\n");
squashIt[tid] = instList[tid].end();
doneSquashing[tid] = true;
return;
}
InstIt tail_thread = instList[tid].end();
tail_thread--;
if ((*squashIt[tid]) == (*tail_thread))
robTailUpdate = true;
squashIt[tid]--;
}
// Check if ROB is done squashing.
if ((*squashIt[tid])->seqNum <= squashedSeqNum[tid]) {
DPRINTF(ROB, "[tid:%u]: Done squashing instructions.\n",
tid);
squashIt[tid] = instList[tid].end();
doneSquashing[tid] = true;
}
if (robTailUpdate) {
updateTail();
}
}
template <class Impl>
void
ROB<Impl>::updateHead()
{
DynInstPtr head_inst;
InstSeqNum lowest_num = 0;
bool first_valid = true;
// @todo: set ActiveThreads through ROB or CPU
list<unsigned>::iterator threads = (*activeThreads).begin();
while (threads != (*activeThreads).end()) {
unsigned thread_num = *threads++;
if (instList[thread_num].empty())
continue;
if (first_valid) {
head = instList[thread_num].begin();
lowest_num = (*head)->seqNum;
first_valid = false;
continue;
}
InstIt head_thread = instList[thread_num].begin();
DynInstPtr head_inst = (*head_thread);
assert(head_inst != 0);
if (head_inst->seqNum < lowest_num) {
head = head_thread;
lowest_num = head_inst->seqNum;
}
}
if (first_valid) {
head = instList[0].end();
}
}
template <class Impl>
void
ROB<Impl>::updateTail()
{
tail = instList[0].end();
bool first_valid = true;
list<unsigned>::iterator threads = (*activeThreads).begin();
while (threads != (*activeThreads).end()) {
unsigned tid = *threads++;
if (instList[tid].empty()) {
continue;
}
// If this is the first valid then assign w/out
// comparison
if (first_valid) {
tail = instList[tid].end();
tail--;
first_valid = false;
continue;
}
// Assign new tail if this thread's tail is younger
// than our current "tail high"
InstIt tail_thread = instList[tid].end();
tail_thread--;
if ((*tail_thread)->seqNum > (*tail)->seqNum) {
tail = tail_thread;
}
}
}
template <class Impl>
void
ROB<Impl>::squash(InstSeqNum squash_num,unsigned tid)
{
if (isEmpty()) {
DPRINTF(ROB, "Does not need to squash due to being empty "
"[sn:%i]\n",
squash_num);
return;
}
DPRINTF(ROB, "Starting to squash within the ROB.\n");
robStatus[tid] = ROBSquashing;
doneSquashing[tid] = false;
squashedSeqNum[tid] = squash_num;
if (!instList[tid].empty()) {
InstIt tail_thread = instList[tid].end();
tail_thread--;
squashIt[tid] = tail_thread;
doSquash(tid);
}
}
/*
template <class Impl>
typename Impl::DynInstPtr
ROB<Impl>::readHeadInst()
{
if (numInstsInROB != 0) {
assert((*head)->isInROB()==true);
return *head;
} else {
return dummyInst;
}
}
*/
template <class Impl>
typename Impl::DynInstPtr
ROB<Impl>::readHeadInst(unsigned tid)
{
if (threadEntries[tid] != 0) {
InstIt head_thread = instList[tid].begin();
assert((*head_thread)->isInROB()==true);
return *head_thread;
} else {
return dummyInst;
}
}
/*
template <class Impl>
uint64_t
ROB<Impl>::readHeadPC()
{
//assert(numInstsInROB == countInsts());
DynInstPtr head_inst = *head;
return head_inst->readPC();
}
template <class Impl>
uint64_t
ROB<Impl>::readHeadPC(unsigned tid)
{
//assert(numInstsInROB == countInsts());
InstIt head_thread = instList[tid].begin();
return (*head_thread)->readPC();
}
template <class Impl>
uint64_t
ROB<Impl>::readHeadNextPC()
{
//assert(numInstsInROB == countInsts());
DynInstPtr head_inst = *head;
return head_inst->readNextPC();
}
template <class Impl>
uint64_t
ROB<Impl>::readHeadNextPC(unsigned tid)
{
//assert(numInstsInROB == countInsts());
InstIt head_thread = instList[tid].begin();
return (*head_thread)->readNextPC();
}
template <class Impl>
InstSeqNum
ROB<Impl>::readHeadSeqNum()
{
//assert(numInstsInROB == countInsts());
DynInstPtr head_inst = *head;
return head_inst->seqNum;
}
template <class Impl>
InstSeqNum
ROB<Impl>::readHeadSeqNum(unsigned tid)
{
InstIt head_thread = instList[tid].begin();
return ((*head_thread)->seqNum);
}
template <class Impl>
typename Impl::DynInstPtr
ROB<Impl>::readTailInst()
{
//assert(numInstsInROB == countInsts());
//assert(tail != instList[0].end());
return (*tail);
}
*/
template <class Impl>
typename Impl::DynInstPtr
ROB<Impl>::readTailInst(unsigned tid)
{
//assert(tail_thread[tid] != instList[tid].end());
InstIt tail_thread = instList[tid].end();
tail_thread--;
return *tail_thread;
}
/*
template <class Impl>
uint64_t
ROB<Impl>::readTailPC()
{
//assert(numInstsInROB == countInsts());
//assert(tail != instList[0].end());
return (*tail)->readPC();
}
template <class Impl>
uint64_t
ROB<Impl>::readTailPC(unsigned tid)
{
//assert(tail_thread[tid] != instList[tid].end());
InstIt tail_thread = instList[tid].end();
tail_thread--;
return (*tail_thread)->readPC();
}
template <class Impl>
InstSeqNum
ROB<Impl>::readTailSeqNum()
{
// Return the last sequence number that has not been squashed. Other
// stages can use it to squash any instructions younger than the current
// tail.
return (*tail)->seqNum;
}
template <class Impl>
InstSeqNum
ROB<Impl>::readTailSeqNum(unsigned tid)
{
// Return the last sequence number that has not been squashed. Other
// stages can use it to squash any instructions younger than the current
// tail.
// assert(tail_thread[tid] != instList[tid].end());
InstIt tail_thread = instList[tid].end();
tail_thread--;
return (*tail_thread)->seqNum;
}
*/