Merge zizzer:/bk/newmem

into  zeep.pool:/z/saidi/work/m5.newmem.head

--HG--
extra : convert_revision : a64362d3cf8de00c97bea25118fee33cffe22707

1 files changed, 871 insertions, 618 deletions

diff --git a/src/cpu/o3/inst_queue_impl.hh b/src/cpu/o3/inst_queue_impl.hh
index 048dc7c00..b99bd0900 100644
--- a/src/cpu/o3/inst_queue_impl.hh
+++ b/src/cpu/o3/inst_queue_impl.hh
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2005 The Regents of The University of Michigan
+ * 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
@@ -24,75 +24,153 @@
  * 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
  */
 
-// Todo:
-// Current ordering allows for 0 cycle added-to-scheduled.  Could maybe fake
-// it; either do in reverse order, or have added instructions put into a
-// different ready queue that, in scheduleRreadyInsts(), gets put onto the
-// normal ready queue.  This would however give only a one cycle delay,
-// but probably is more flexible to actually add in a delay parameter than
-// just running it backwards.
-
 #include <limits>
 #include <vector>
 
 #include "sim/root.hh"
 
+#include "cpu/o3/fu_pool.hh"
 #include "cpu/o3/inst_queue.hh"
 
-// Either compile error or max int due to sign extension.
-// Hack to avoid compile warnings.
-const InstSeqNum MaxInstSeqNum = std::numeric_limits<InstSeqNum>::max();
+using namespace std;
 
 template <class Impl>
-InstructionQueue<Impl>::InstructionQueue(Params &params)
-    : memDepUnit(params),
-      numEntries(params.numIQEntries),
-      intWidth(params.executeIntWidth),
-      floatWidth(params.executeFloatWidth),
-      branchWidth(params.executeBranchWidth),
-      memoryWidth(params.executeMemoryWidth),
-      totalWidth(params.issueWidth),
-      numPhysIntRegs(params.numPhysIntRegs),
-      numPhysFloatRegs(params.numPhysFloatRegs),
-      commitToIEWDelay(params.commitToIEWDelay)
+InstructionQueue<Impl>::FUCompletion::FUCompletion(DynInstPtr &_inst,
+                                                   int fu_idx,
+                                                   InstructionQueue<Impl> *iq_ptr)
+    : Event(&mainEventQueue, Stat_Event_Pri),
+      inst(_inst), fuIdx(fu_idx), iqPtr(iq_ptr), freeFU(false)
 {
-    // Initialize the number of free IQ entries.
-    freeEntries = numEntries;
+    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()
+{
+    return "Functional unit completion event";
+}
+
+template <class Impl>
+InstructionQueue<Impl>::InstructionQueue(Params *params)
+    : fuPool(params->fuPool),
+      numEntries(params->numIQEntries),
+      totalWidth(params->issueWidth),
+      numPhysIntRegs(params->numPhysIntRegs),
+      numPhysFloatRegs(params->numPhysFloatRegs),
+      commitToIEWDelay(params->commitToIEWDelay)
+{
+    assert(fuPool);
+
+    switchedOut = false;
+
+    numThreads = params->numberOfThreads;
 
     // Set the number of physical registers as the number of int + float
     numPhysRegs = numPhysIntRegs + numPhysFloatRegs;
 
-    DPRINTF(IQ, "IQ: There are %i physical registers.\n", numPhysRegs);
+    DPRINTF(IQ, "There are %i physical registers.\n", numPhysRegs);
 
     //Create an entry for each physical register within the
     //dependency graph.
-    dependGraph = new DependencyEntry[numPhysRegs];
+    dependGraph.resize(numPhysRegs);
 
     // Resize the register scoreboard.
     regScoreboard.resize(numPhysRegs);
 
-    // Initialize all the head pointers to point to NULL, and all the
-    // entries as unready.
-    // 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)
-    {
-        dependGraph[i].next = NULL;
-        dependGraph[i].inst = NULL;
-        regScoreboard[i] = false;
+    //Initialize Mem Dependence Units
+    for (int i = 0; i < numThreads; i++) {
+        memDepUnit[i].init(params,i);
+        memDepUnit[i].setIQ(this);
     }
 
+    resetState();
+
+    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)")
@@ -103,36 +181,31 @@ InstructionQueue<Impl>::regStats()
         .desc("Number of non-speculative instructions added to the IQ")
         .prereq(iqNonSpecInstsAdded);
 
-//    iqIntInstsAdded;
+    iqInstsIssued
+        .name(name() + ".iqInstsIssued")
+        .desc("Number of instructions issued")
+        .prereq(iqInstsIssued);
 
     iqIntInstsIssued
         .name(name() + ".iqIntInstsIssued")
         .desc("Number of integer instructions issued")
         .prereq(iqIntInstsIssued);
 
-//    iqFloatInstsAdded;
-
     iqFloatInstsIssued
         .name(name() + ".iqFloatInstsIssued")
         .desc("Number of float instructions issued")
         .prereq(iqFloatInstsIssued);
 
-//    iqBranchInstsAdded;
-
     iqBranchInstsIssued
         .name(name() + ".iqBranchInstsIssued")
         .desc("Number of branch instructions issued")
         .prereq(iqBranchInstsIssued);
 
-//    iqMemInstsAdded;
-
     iqMemInstsIssued
         .name(name() + ".iqMemInstsIssued")
         .desc("Number of memory instructions issued")
         .prereq(iqMemInstsIssued);
 
-//    iqMiscInstsAdded;
-
     iqMiscInstsIssued
         .name(name() + ".iqMiscInstsIssued")
         .desc("Number of miscellaneous instructions issued")
@@ -143,12 +216,6 @@ InstructionQueue<Impl>::regStats()
         .desc("Number of squashed instructions issued")
         .prereq(iqSquashedInstsIssued);
 
-    iqLoopSquashStalls
-        .name(name() + ".iqLoopSquashStalls")
-        .desc("Number of times issue loop had to restart due to squashed "
-              "inst; mainly for profiling")
-        .prereq(iqLoopSquashStalls);
-
     iqSquashedInstsExamined
         .name(name() + ".iqSquashedInstsExamined")
         .desc("Number of squashed instructions iterated over during squash;"
@@ -166,25 +233,143 @@ InstructionQueue<Impl>::regStats()
         .desc("Number of squashed non-spec instructions that were removed")
         .prereq(iqSquashedNonSpecRemoved);
 
-    // Tell mem dependence unit to reg stats as well.
-    memDepUnit.regStats();
+    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,Num_OpClasses)
+        .name(name() + ".ISSUE:FU_type")
+        .desc("Type of FU issued")
+        .flags(total | pdf | dist)
+        ;
+    statIssuedInstType.ysubnames(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) {
+        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, 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>::setCPU(FullCPU *cpu_ptr)
+InstructionQueue<Impl>::resetState()
 {
-    cpu = cpu_ptr;
+    //Initialize thread IQ counts
+    for (int i = 0; i <numThreads; i++) {
+        count[i] = 0;
+        instList[i].clear();
+    }
 
-    tail = cpu->instList.begin();
+    // 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>::setIssueToExecuteQueue(
-                        TimeBuffer<IssueStruct> *i2e_ptr)
+InstructionQueue<Impl>::setActiveThreads(list<unsigned> *at_ptr)
 {
-    DPRINTF(IQ, "IQ: Set the issue to execute queue.\n");
+    DPRINTF(IQ, "Setting active threads list pointer.\n");
+    activeThreads = at_ptr;
+}
+
+template <class Impl>
+void
+InstructionQueue<Impl>::setIssueToExecuteQueue(TimeBuffer<IssueStruct> *i2e_ptr)
+{
+    DPRINTF(IQ, "Set the issue to execute queue.\n");
     issueToExecuteQueue = i2e_ptr;
 }
 
@@ -192,19 +377,77 @@ template <class Impl>
 void
 InstructionQueue<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr)
 {
-    DPRINTF(IQ, "IQ: Set the time buffer.\n");
+    DPRINTF(IQ, "Set the time buffer.\n");
     timeBuffer = tb_ptr;
 
     fromCommit = timeBuffer->getWire(-commitToIEWDelay);
 }
 
 template <class Impl>
+void
+InstructionQueue<Impl>::switchOut()
+{
+    resetState();
+    dependGraph.reset();
+    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();
+
+        list<unsigned>::iterator threads  = (*activeThreads).begin();
+        list<unsigned>::iterator list_end = (*activeThreads).end();
+
+        while (threads != list_end) {
+            if (iqPolicy == Partitioned) {
+                maxEntries[*threads++] = numEntries / active_threads;
+            } else if(iqPolicy == Threshold && active_threads == 1) {
+                maxEntries[*threads++] = 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>
@@ -219,447 +462,412 @@ InstructionQueue<Impl>::isFull()
 }
 
 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, "IQ: Adding instruction PC %#x to the IQ.\n",
-            new_inst->readPC());
+    DPRINTF(IQ, "Adding instruction [sn:%lli] PC %#x to the IQ.\n",
+            new_inst->seqNum, new_inst->readPC());
 
-    // Check if there are any free entries.  Panic if there are none.
-    // Might want to have this return a fault in the future instead of
-    // panicing.
     assert(freeEntries != 0);
 
-    // If the IQ currently has nothing in it, then there's a possibility
-    // that the tail iterator is invalid (might have been pointing at an
-    // instruction that was retired).  Reset the tail iterator.
-    if (freeEntries == numEntries) {
-        tail = cpu->instList.begin();
-    }
+    instList[new_inst->threadNumber].push_back(new_inst);
 
-    // Move the tail iterator.  Instructions may not have been issued
-    // to the IQ, so we may have to increment the iterator more than once.
-    while ((*tail) != new_inst) {
-        tail++;
-
-        // Make sure the tail iterator points at something legal.
-        assert(tail != cpu->instList.end());
-    }
-
-
-    // Decrease the number of free entries.
     --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).
-    createDependency(new_inst);
+    addToProducers(new_inst);
 
-    // If it's a memory instruction, add it to the memory dependency
-    // unit.
     if (new_inst->isMemRef()) {
-        memDepUnit.insert(new_inst);
-        // Uh..forgot to look it up and put it on the proper dependency list
-        // if the instruction should not go yet.
+        memDepUnit[new_inst->threadNumber].insert(new_inst);
     } else {
-        // If the instruction is ready then add it to the ready list.
         addIfReady(new_inst);
     }
 
     ++iqInstsAdded;
 
+    count[new_inst->threadNumber]++;
+
     assert(freeEntries == (numEntries - countInsts()));
 }
 
 template <class Impl>
 void
-InstructionQueue<Impl>::insertNonSpec(DynInstPtr &inst)
+InstructionQueue<Impl>::insertNonSpec(DynInstPtr &new_inst)
 {
-    nonSpecInsts[inst->seqNum] = inst;
-
     // @todo: Clean up this code; can do it by setting inst as unable
     // to issue, then calling normal insert on the inst.
 
-    // Make sure the instruction is valid
-    assert(inst);
+    assert(new_inst);
 
-    DPRINTF(IQ, "IQ: Adding instruction PC %#x to the IQ.\n",
-            inst->readPC());
+    nonSpecInsts[new_inst->seqNum] = new_inst;
 
-    // Check if there are any free entries.  Panic if there are none.
-    // Might want to have this return a fault in the future instead of
-    // panicing.
-    assert(freeEntries != 0);
+    DPRINTF(IQ, "Adding non-speculative instruction [sn:%lli] PC %#x "
+            "to the IQ.\n",
+            new_inst->seqNum, new_inst->readPC());
 
-    // If the IQ currently has nothing in it, then there's a possibility
-    // that the tail iterator is invalid (might have been pointing at an
-    // instruction that was retired).  Reset the tail iterator.
-    if (freeEntries == numEntries) {
-        tail = cpu->instList.begin();
-    }
-
-    // Move the tail iterator.  Instructions may not have been issued
-    // to the IQ, so we may have to increment the iterator more than once.
-    while ((*tail) != inst) {
-        tail++;
+    assert(freeEntries != 0);
 
-        // Make sure the tail iterator points at something legal.
-        assert(tail != cpu->instList.end());
-    }
+    instList[new_inst->threadNumber].push_back(new_inst);
 
-    // Decrease the number of free entries.
     --freeEntries;
 
+    new_inst->setInIQ();
+
     // Have this instruction set itself as the producer of its destination
     // register(s).
-    createDependency(inst);
+    addToProducers(new_inst);
 
     // If it's a memory instruction, add it to the memory dependency
     // unit.
-    if (inst->isMemRef()) {
-        memDepUnit.insertNonSpec(inst);
+    if (new_inst->isMemRef()) {
+        memDepUnit[new_inst->threadNumber].insertNonSpec(new_inst);
     }
 
     ++iqNonSpecInstsAdded;
+
+    count[new_inst->threadNumber]++;
+
+    assert(freeEntries == (numEntries - countInsts()));
 }
 
-// Slightly hack function to advance the tail iterator in the case that
-// the IEW stage issues an instruction that is not added to the IQ.  This
-// is needed in case a long chain of such instructions occurs.
-// I don't think this is used anymore.
 template <class Impl>
 void
-InstructionQueue<Impl>::advanceTail(DynInstPtr &inst)
+InstructionQueue<Impl>::insertBarrier(DynInstPtr &barr_inst)
 {
-    // Make sure the instruction is valid
-    assert(inst);
-
-    DPRINTF(IQ, "IQ: Adding instruction PC %#x to the IQ.\n",
-            inst->readPC());
+    memDepUnit[barr_inst->threadNumber].insertBarrier(barr_inst);
 
-    // Check if there are any free entries.  Panic if there are none.
-    // Might want to have this return a fault in the future instead of
-    // panicing.
-    assert(freeEntries != 0);
-
-    // If the IQ currently has nothing in it, then there's a possibility
-    // that the tail iterator is invalid (might have been pointing at an
-    // instruction that was retired).  Reset the tail iterator.
-    if (freeEntries == numEntries) {
-        tail = cpu->instList.begin();
-    }
-
-    // Move the tail iterator.  Instructions may not have been issued
-    // to the IQ, so we may have to increment the iterator more than once.
-    while ((*tail) != inst) {
-        tail++;
-
-        // Make sure the tail iterator points at something legal.
-        assert(tail != cpu->instList.end());
-    }
-
-    assert(freeEntries <= numEntries);
+    insertNonSpec(barr_inst);
+}
 
-    // Have this instruction set itself as the producer of its destination
-    // register(s).
-    createDependency(inst);
+template <class Impl>
+typename Impl::DynInstPtr
+InstructionQueue<Impl>::getInstToExecute()
+{
+    assert(!instsToExecute.empty());
+    DynInstPtr inst = instsToExecute.front();
+    instsToExecute.pop_front();
+    return inst;
 }
 
-// Need to make sure the number of float and integer instructions
-// issued does not exceed the total issue bandwidth.
-// @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()
+InstructionQueue<Impl>::addToOrderList(OpClass op_class)
 {
-    DPRINTF(IQ, "IQ: Attempting to schedule ready instructions from "
-                "the IQ.\n");
-
-    int int_issued = 0;
-    int float_issued = 0;
-    int branch_issued = 0;
-    int memory_issued = 0;
-    int squashed_issued = 0;
-    int total_issued = 0;
-
-    IssueStruct *i2e_info = issueToExecuteQueue->access(0);
-
-    bool insts_available = !readyBranchInsts.empty() ||
-        !readyIntInsts.empty() ||
-        !readyFloatInsts.empty() ||
-        !memDepUnit.empty() ||
-        !readyMiscInsts.empty() ||
-        !squashedInsts.empty();
-
-    // Note: Requires a globally defined constant.
-    InstSeqNum oldest_inst = MaxInstSeqNum;
-    InstList list_with_oldest = None;
-
-    // Temporary values.
-    DynInstPtr int_head_inst;
-    DynInstPtr float_head_inst;
-    DynInstPtr branch_head_inst;
-    DynInstPtr mem_head_inst;
-    DynInstPtr misc_head_inst;
-    DynInstPtr squashed_head_inst;
-
-    // Somewhat nasty code to look at all of the lists where issuable
-    // instructions are located, and choose the oldest instruction among
-    // those lists.  Consider a rewrite in the future.
-    while (insts_available && total_issued < totalWidth)
-    {
-        // Set this to false.  Each if-block is required to set it to true
-        // if there were instructions available this check.  This will cause
-        // this loop to run once more than necessary, but avoids extra calls.
-        insts_available = false;
-
-        oldest_inst = MaxInstSeqNum;
+    assert(!readyInsts[op_class].empty());
 
-        list_with_oldest = None;
+    ListOrderEntry queue_entry;
 
-        if (!readyIntInsts.empty() &&
-            int_issued < intWidth) {
+    queue_entry.queueType = op_class;
 
-            insts_available = true;
+    queue_entry.oldestInst = readyInsts[op_class].top()->seqNum;
 
-            int_head_inst = readyIntInsts.top();
+    ListOrderIt list_it = listOrder.begin();
+    ListOrderIt list_end_it = listOrder.end();
 
-            if (int_head_inst->isSquashed()) {
-                readyIntInsts.pop();
-
-                ++iqLoopSquashStalls;
-
-                continue;
-            }
-
-            oldest_inst = int_head_inst->seqNum;
-
-            list_with_oldest = Int;
+    while (list_it != list_end_it) {
+        if ((*list_it).oldestInst > queue_entry.oldestInst) {
+            break;
         }
 
-        if (!readyFloatInsts.empty() &&
-            float_issued < floatWidth) {
-
-            insts_available = true;
-
-            float_head_inst = readyFloatInsts.top();
-
-            if (float_head_inst->isSquashed()) {
-                readyFloatInsts.pop();
-
-                ++iqLoopSquashStalls;
-
-                continue;
-            } else if (float_head_inst->seqNum < oldest_inst) {
-                oldest_inst = float_head_inst->seqNum;
+        list_it++;
+    }
 
-                list_with_oldest = Float;
-            }
-        }
+    readyIt[op_class] = listOrder.insert(list_it, queue_entry);
+    queueOnList[op_class] = true;
+}
 
-        if (!readyBranchInsts.empty() &&
-            branch_issued < branchWidth) {
+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;
+    }
 
-            insts_available = true;
+    readyIt[op_class] = listOrder.insert(next_it, queue_entry);
+}
 
-            branch_head_inst = readyBranchInsts.top();
+template <class Impl>
+void
+InstructionQueue<Impl>::processFUCompletion(DynInstPtr &inst, int fu_idx)
+{
+    // 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()) {
+        return;
+    }
 
-            if (branch_head_inst->isSquashed()) {
-                readyBranchInsts.pop();
+    iewStage->wakeCPU();
 
-                ++iqLoopSquashStalls;
+    if (fu_idx > -1)
+        fuPool->freeUnitNextCycle(fu_idx);
 
-                continue;
-            } else if (branch_head_inst->seqNum < oldest_inst) {
-                oldest_inst = branch_head_inst->seqNum;
+    // @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(0)->size++;
+    instsToExecute.push_back(inst);
+}
 
-                list_with_oldest = Branch;
-            }
+// @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);
 
-        if (!memDepUnit.empty() &&
-            memory_issued < memoryWidth) {
+    // 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;
 
-            insts_available = true;
+    while (total_issued < totalWidth &&
+           order_it != order_end_it) {
+        OpClass op_class = (*order_it).queueType;
 
-            mem_head_inst = memDepUnit.top();
+        assert(!readyInsts[op_class].empty());
 
-            if (mem_head_inst->isSquashed()) {
-                memDepUnit.pop();
+        DynInstPtr issuing_inst = readyInsts[op_class].top();
 
-                ++iqLoopSquashStalls;
+        assert(issuing_inst->seqNum == (*order_it).oldestInst);
 
-                continue;
-            } else if (mem_head_inst->seqNum < oldest_inst) {
-                oldest_inst = mem_head_inst->seqNum;
+        if (issuing_inst->isSquashed()) {
+            readyInsts[op_class].pop();
 
-                list_with_oldest = Memory;
+            if (!readyInsts[op_class].empty()) {
+                moveToYoungerInst(order_it);
+            } else {
+                readyIt[op_class] = listOrder.end();
+                queueOnList[op_class] = false;
             }
-        }
-
-        if (!readyMiscInsts.empty()) {
 
-            insts_available = true;
+            listOrder.erase(order_it++);
 
-            misc_head_inst = readyMiscInsts.top();
+            ++iqSquashedInstsIssued;
 
-            if (misc_head_inst->isSquashed()) {
-                readyMiscInsts.pop();
-
-                ++iqLoopSquashStalls;
-
-                continue;
-            } else if (misc_head_inst->seqNum < oldest_inst) {
-                oldest_inst = misc_head_inst->seqNum;
-
-                list_with_oldest = Misc;
-            }
+            continue;
         }
 
-        if (!squashedInsts.empty()) {
+        int idx = -2;
+        int op_latency = 1;
+        int tid = issuing_inst->threadNumber;
 
-            insts_available = true;
+        if (op_class != No_OpClass) {
+            idx = fuPool->getUnit(op_class);
 
-            squashed_head_inst = squashedInsts.top();
-
-            if (squashed_head_inst->seqNum < oldest_inst) {
-                list_with_oldest = Squashed;
+            if (idx > -1) {
+                op_latency = fuPool->getOpLatency(op_class);
             }
-
         }
 
-        DynInstPtr issuing_inst = NULL;
-
-        switch (list_with_oldest) {
-          case None:
-            DPRINTF(IQ, "IQ: Not able to schedule any instructions. Issuing "
-                    "inst is %#x.\n", issuing_inst);
-            break;
-
-          case Int:
-            issuing_inst = int_head_inst;
-            readyIntInsts.pop();
-            ++int_issued;
-            DPRINTF(IQ, "IQ: Issuing integer instruction PC %#x.\n",
-                    issuing_inst->readPC());
-            break;
-
-          case Float:
-            issuing_inst = float_head_inst;
-            readyFloatInsts.pop();
-            ++float_issued;
-            DPRINTF(IQ, "IQ: Issuing float instruction PC %#x.\n",
-                    issuing_inst->readPC());
-            break;
-
-          case Branch:
-            issuing_inst = branch_head_inst;
-            readyBranchInsts.pop();
-            ++branch_issued;
-            DPRINTF(IQ, "IQ: Issuing branch instruction PC %#x.\n",
-                    issuing_inst->readPC());
-            break;
-
-          case Memory:
-            issuing_inst = mem_head_inst;
+        // 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);
+
+                execution->schedule(curTick + cpu->cycles(issue_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);
+                }
+            }
 
-            memDepUnit.pop();
-            ++memory_issued;
-            DPRINTF(IQ, "IQ: Issuing memory instruction PC %#x.\n",
-                    issuing_inst->readPC());
-            break;
+            DPRINTF(IQ, "Thread %i: Issuing instruction PC %#x "
+                    "[sn:%lli]\n",
+                    tid, issuing_inst->readPC(),
+                    issuing_inst->seqNum);
 
-          case Misc:
-            issuing_inst = misc_head_inst;
-            readyMiscInsts.pop();
+            readyInsts[op_class].pop();
 
-            ++iqMiscInstsIssued;
+            if (!readyInsts[op_class].empty()) {
+                moveToYoungerInst(order_it);
+            } else {
+                readyIt[op_class] = listOrder.end();
+                queueOnList[op_class] = false;
+            }
 
-            DPRINTF(IQ, "IQ: Issuing a miscellaneous instruction PC %#x.\n",
-                    issuing_inst->readPC());
-            break;
+            issuing_inst->setIssued();
+            ++total_issued;
 
-          case Squashed:
-            assert(0 && "Squashed insts should not issue any more!");
-            squashedInsts.pop();
-            // Set the squashed instruction as able to commit so that commit
-            // can just drop it from the ROB.  This is a bit faked.
-            ++squashed_issued;
-            ++freeEntries;
+            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);
+            }
 
-            DPRINTF(IQ, "IQ: Issuing squashed instruction PC %#x.\n",
-                    squashed_head_inst->readPC());
-            break;
+            listOrder.erase(order_it++);
+            statIssuedInstType[tid][op_class]++;
+        } else {
+            statFuBusy[op_class]++;
+            fuBusy[tid]++;
+            ++order_it;
         }
+    }
 
-        if (list_with_oldest != None && list_with_oldest != Squashed) {
-            i2e_info->insts[total_issued] = issuing_inst;
-            i2e_info->size++;
-
-            issuing_inst->setIssued();
+    numIssuedDist.sample(total_issued);
+    iqInstsIssued+= total_issued;
 
-            ++freeEntries;
-            ++total_issued;
-        }
-
-        assert(freeEntries == (numEntries - countInsts()));
+    // 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");
     }
-
-    iqIntInstsIssued += int_issued;
-    iqFloatInstsIssued += float_issued;
-    iqBranchInstsIssued += branch_issued;
-    iqMemInstsIssued += memory_issued;
-    iqSquashedInstsIssued += squashed_issued;
 }
 
 template <class Impl>
 void
 InstructionQueue<Impl>::scheduleNonSpec(const InstSeqNum &inst)
 {
-    DPRINTF(IQ, "IQ: Marking nonspeculative instruction with sequence "
-            "number %i as ready to execute.\n", inst);
+    DPRINTF(IQ, "Marking nonspeculative instruction [sn:%lli] as ready "
+            "to execute.\n", inst);
 
-    non_spec_it_t inst_it = nonSpecInsts.find(inst);
+    NonSpecMapIt inst_it = nonSpecInsts.find(inst);
 
     assert(inst_it != nonSpecInsts.end());
 
-    // Mark this instruction as ready to issue.
+    unsigned tid = (*inst_it).second->threadNumber;
+
     (*inst_it).second->setCanIssue();
 
-    // Now schedule the instruction.
     if (!(*inst_it).second->isMemRef()) {
         addIfReady((*inst_it).second);
     } else {
-        memDepUnit.nonSpecInstReady((*inst_it).second);
+        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)
 {
-    DPRINTF(IQ, "IQ: Waking dependents of completed instruction.\n");
-    //Look at the physical destination register of the DynInst
-    //and look it up on the dependency graph.  Then mark as ready
-    //any instructions within the instruction queue.
-    DependencyEntry *curr;
+    int dependents = 0;
 
-    // Tell the memory dependence unit to wake any dependents on this
-    // instruction if it is a memory instruction.
+    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.wakeDependents(completed_inst);
+        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;
@@ -676,44 +884,94 @@ InstructionQueue<Impl>::wakeDependents(DynInstPtr &completed_inst)
             continue;
         }
 
-        DPRINTF(IQ, "IQ: Waking any dependents on register %i.\n",
+        DPRINTF(IQ, "Waking any dependents on register %i.\n",
                 (int) dest_reg);
 
-        //Maybe abstract this part into a function.
-        //Go through the dependency chain, marking the registers as ready
-        //within the waiting instructions.
-        while (dependGraph[dest_reg].next) {
+        //Go through the dependency chain, marking the registers as
+        //ready within the waiting instructions.
+        DynInstPtr dep_inst = dependGraph.pop(dest_reg);
 
-            curr = dependGraph[dest_reg].next;
-
-            DPRINTF(IQ, "IQ: Waking up a dependent instruction, PC%#x.\n",
-                    curr->inst->readPC());
+        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.
-            curr->inst->markSrcRegReady();
-
-            addIfReady(curr->inst);
-
-            dependGraph[dest_reg].next = curr->next;
+            // 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();
 
-            DependencyEntry::mem_alloc_counter--;
+            addIfReady(dep_inst);
 
-            curr->inst = NULL;
+            dep_inst = dependGraph.pop(dest_reg);
 
-            delete curr;
+            ++dependents;
         }
 
-        // Reset the head node now that all of its dependents have been woken
-        // up.
-        dependGraph[dest_reg].next = NULL;
-        dependGraph[dest_reg].inst = NULL;
+        // 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)
+{
+    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>
@@ -721,58 +979,64 @@ void
 InstructionQueue<Impl>::violation(DynInstPtr &store,
                                   DynInstPtr &faulting_load)
 {
-    memDepUnit.violation(store, faulting_load);
+    memDepUnit[store->threadNumber].violation(store, faulting_load);
 }
 
 template <class Impl>
 void
-InstructionQueue<Impl>::squash()
+InstructionQueue<Impl>::squash(unsigned tid)
 {
-    DPRINTF(IQ, "IQ: Starting to squash instructions in the IQ.\n");
+    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 = fromCommit->commitInfo.doneSeqNum;
-
-    // Setup the squash iterator to point to the tail.
-    squashIt = tail;
+    squashedSeqNum[tid] = fromCommit->commitInfo[tid].doneSeqNum;
 
     // Call doSquash if there are insts in the IQ
-    if (freeEntries != numEntries) {
-        doSquash();
+    if (count[tid] > 0) {
+        doSquash(tid);
     }
 
     // Also tell the memory dependence unit to squash.
-    memDepUnit.squash(squashedSeqNum);
+    memDepUnit[tid].squash(squashedSeqNum[tid], tid);
 }
 
 template <class Impl>
 void
-InstructionQueue<Impl>::doSquash()
+InstructionQueue<Impl>::doSquash(unsigned tid)
 {
-    // Make sure the squash iterator isn't pointing to nothing.
-    assert(squashIt != cpu->instList.end());
-    // Make sure the squashed sequence number is valid.
-    assert(squashedSeqNum != 0);
+    // Start at the tail.
+    ListIt squash_it = instList[tid].end();
+    --squash_it;
 
-    DPRINTF(IQ, "IQ: Squashing instructions in the IQ.\n");
+    DPRINTF(IQ, "[tid:%i]: Squashing until sequence number %i!\n",
+            tid, squashedSeqNum[tid]);
 
     // Squash any instructions younger than the squashed sequence number
     // given.
-    while ((*squashIt)->seqNum > squashedSeqNum) {
-        DynInstPtr squashed_inst = (*squashIt);
+    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->isIssued() &&
-            !squashed_inst->isSquashedInIQ()) {
+        if (squashed_inst->threadNumber != tid ||
+            squashed_inst->isSquashedInIQ()) {
+            --squash_it;
+            continue;
+        }
+
+        if (!squashed_inst->isIssued() ||
+            (squashed_inst->isMemRef() &&
+             !squashed_inst->memOpDone)) {
 
             // Remove the instruction from the dependency list.
-            // Hack for now: These below don't add themselves to the
-            // dependency list, so don't try to remove them.
-            if (!squashed_inst->isNonSpeculative()/* &&
-                                                     !squashed_inst->isStore()*/
-                ) {
+            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();
@@ -781,25 +1045,31 @@ InstructionQueue<Impl>::doSquash()
                     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.
-                    // HACK: This assumes that instructions woken up from the
-                    // dependency chain aren't informed that a specific src
-                    // register has become ready.  This may not always be true
-                    // in the future.
+                    // 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[src_reg].remove(squashed_inst);
+                        dependGraph.remove(src_reg, squashed_inst);
                     }
 
+
                     ++iqSquashedOperandsExamined;
                 }
-
-                // Might want to remove producers as well.
             } else {
-                nonSpecInsts[squashed_inst->seqNum] = NULL;
+                NonSpecMapIt ns_inst_it =
+                    nonSpecInsts.find(squashed_inst->seqNum);
+                assert(ns_inst_it != nonSpecInsts.end());
 
-                nonSpecInsts.erase(squashed_inst->seqNum);
+                (*ns_inst_it).second = NULL;
+
+                nonSpecInsts.erase(ns_inst_it);
 
                 ++iqSquashedNonSpecRemoved;
             }
@@ -809,91 +1079,25 @@ InstructionQueue<Impl>::doSquash()
             // Mark it as squashed within the IQ.
             squashed_inst->setSquashedInIQ();
 
-//            squashedInsts.push(squashed_inst);
+            // @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;
 
-            DPRINTF(IQ, "IQ: Instruction PC %#x squashed.\n",
-                    squashed_inst->readPC());
+            DPRINTF(IQ, "[tid:%i]: Instruction [sn:%lli] PC %#x "
+                    "squashed.\n",
+                    tid, squashed_inst->seqNum, squashed_inst->readPC());
         }
 
-        --squashIt;
+        instList[tid].erase(squash_it--);
         ++iqSquashedInstsExamined;
     }
-
-    assert(freeEntries <= numEntries);
-
-    if (freeEntries == numEntries) {
-        tail = cpu->instList.end();
-    }
-
-}
-
-template <class Impl>
-void
-InstructionQueue<Impl>::stopSquash()
-{
-    // Clear up the squash variables to ensure that squashing doesn't
-    // get called improperly.
-    squashedSeqNum = 0;
-
-    squashIt = cpu->instList.end();
-}
-
-template <class Impl>
-void
-InstructionQueue<Impl>::DependencyEntry::insert(DynInstPtr &new_inst)
-{
-    //Add this new, dependent instruction at the head of the dependency
-    //chain.
-
-    // First create the entry that will be added to the head of the
-    // dependency chain.
-    DependencyEntry *new_entry = new DependencyEntry;
-    new_entry->next = this->next;
-    new_entry->inst = new_inst;
-
-    // Then actually add it to the chain.
-    this->next = new_entry;
-
-    ++mem_alloc_counter;
-}
-
-template <class Impl>
-void
-InstructionQueue<Impl>::DependencyEntry::remove(DynInstPtr &inst_to_remove)
-{
-    DependencyEntry *prev = this;
-    DependencyEntry *curr = this->next;
-
-    // Make sure curr isn't NULL.  Because this instruction is being
-    // removed from a dependency list, it must have been placed there at
-    // an earlier time.  The dependency chain should not be empty,
-    // unless the instruction dependent upon it is already ready.
-    if (curr == NULL) {
-        return;
-    }
-
-    // Find the instruction to remove within the dependency linked list.
-    while(curr->inst != inst_to_remove)
-    {
-        prev = curr;
-        curr = curr->next;
-
-        assert(curr != NULL);
-    }
-
-    // Now remove this instruction from the list.
-    prev->next = curr->next;
-
-    --mem_alloc_counter;
-
-    // Could push this off to the destructor of DependencyEntry
-    curr->inst = NULL;
-
-    delete curr;
 }
 
 template <class Impl>
@@ -920,21 +1124,21 @@ InstructionQueue<Impl>::addToDependents(DynInstPtr &new_inst)
             if (src_reg >= numPhysRegs) {
                 continue;
             } else if (regScoreboard[src_reg] == false) {
-                DPRINTF(IQ, "IQ: Instruction PC %#x has src reg %i that "
+                DPRINTF(IQ, "Instruction PC %#x has src reg %i that "
                         "is being added to the dependency chain.\n",
                         new_inst->readPC(), src_reg);
 
-                dependGraph[src_reg].insert(new_inst);
+                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, "IQ: Instruction PC %#x has src reg %i that "
+                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();
+                new_inst->markSrcRegReady(src_reg_idx);
             }
         }
     }
@@ -944,12 +1148,12 @@ InstructionQueue<Impl>::addToDependents(DynInstPtr &new_inst)
 
 template <class Impl>
 void
-InstructionQueue<Impl>::createDependency(DynInstPtr &new_inst)
+InstructionQueue<Impl>::addToProducers(DynInstPtr &new_inst)
 {
-    //Actually 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.
+    // 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;
@@ -966,13 +1170,13 @@ InstructionQueue<Impl>::createDependency(DynInstPtr &new_inst)
             continue;
         }
 
-        dependGraph[dest_reg].inst = new_inst;
-
-        if (dependGraph[dest_reg].next) {
-            dumpDependGraph();
-            panic("IQ: Dependency graph not empty!");
+        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;
     }
@@ -982,155 +1186,204 @@ template <class Impl>
 void
 InstructionQueue<Impl>::addIfReady(DynInstPtr &inst)
 {
-    //If the instruction now has all of its source registers
+    // 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->isControl()) {
+        if (inst->isMemRef()) {
 
-            DPRINTF(IQ, "IQ: Branch instruction is ready to issue, "
-                    "putting it onto the ready list, PC %#x.\n",
-                    inst->readPC());
-            readyBranchInsts.push(inst);
-
-        } else if (inst->isMemRef()) {
-
-            DPRINTF(IQ, "IQ: Checking if memory instruction can issue.\n");
+            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);
 
-            memDepUnit.regsReady(inst);
-
-#if 0
-            if (memDepUnit.readyToIssue(inst)) {
-                DPRINTF(IQ, "IQ: Memory instruction is ready to issue, "
-                        "putting it onto the ready list, PC %#x.\n",
-                        inst->readPC());
-                readyMemInsts.push(inst);
-            } else {
-                // Make dependent on the store.
-                // Will need some way to get the store instruction it should
-                // be dependent upon; then when the store issues it can
-                // put the instruction on the ready list.
-                // Yet another tree?
-                assert(0 && "Instruction has no way to actually issue");
-            }
-#endif
-
-        } else if (inst->isInteger()) {
-
-            DPRINTF(IQ, "IQ: Integer instruction is ready to issue, "
-                    "putting it onto the ready list, PC %#x.\n",
-                    inst->readPC());
-            readyIntInsts.push(inst);
+            return;
+        }
 
-        } else if (inst->isFloating()) {
+        OpClass op_class = inst->opClass();
 
-            DPRINTF(IQ, "IQ: Floating instruction is ready to issue, "
-                    "putting it onto the ready list, PC %#x.\n",
-                    inst->readPC());
-            readyFloatInsts.push(inst);
+        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);
 
-        } else {
-            DPRINTF(IQ, "IQ: Miscellaneous instruction is ready to issue, "
-                    "putting it onto the ready list, PC %#x..\n",
-                    inst->readPC());
+        readyInsts[op_class].push(inst);
 
-            readyMiscInsts.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);
         }
     }
 }
 
-/*
- * Caution, this function must not be called prior to tail being updated at
- * least once, otherwise it will fail the assertion.  This is because
- * instList.begin() actually changes upon the insertion of an element into the
- * list when the list is empty.
- */
 template <class Impl>
 int
 InstructionQueue<Impl>::countInsts()
 {
-    ListIt count_it = cpu->instList.begin();
+#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;
 
-    if (tail == cpu->instList.end())
-        return 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;
+                }
+            }
 
-    while (count_it != tail) {
-        if (!(*count_it)->isIssued()) {
-            ++total_insts;
+            ++count_it;
         }
-
-        ++count_it;
-
-        assert(count_it != cpu->instList.end());
-    }
-
-    // Need to count the tail iterator as well.
-    if (count_it != cpu->instList.end() &&
-        (*count_it) &&
-        !(*count_it)->isIssued()) {
-        ++total_insts;
     }
 
     return total_insts;
+#else
+    return numEntries - freeEntries;
+#endif
 }
 
 template <class Impl>
 void
-InstructionQueue<Impl>::dumpDependGraph()
+InstructionQueue<Impl>::dumpLists()
 {
-    DependencyEntry *curr;
+    for (int i = 0; i < Num_OpClasses; ++i) {
+        cprintf("Ready list %i size: %i\n", i, readyInsts[i].size());
 
-    for (int i = 0; i < numPhysRegs; ++i)
-    {
-        curr = &dependGraph[i];
+        cprintf("\n");
+    }
 
-        if (curr->inst) {
-            cprintf("dependGraph[%i]: producer: %#x consumer: ", i,
-                    curr->inst->readPC());
-        } else {
-            cprintf("dependGraph[%i]: No producer. consumer: ", i);
-        }
+    cprintf("Non speculative list size: %i\n", nonSpecInsts.size());
 
-        while (curr->next != NULL) {
-            curr = curr->next;
+    NonSpecMapIt non_spec_it = nonSpecInsts.begin();
+    NonSpecMapIt non_spec_end_it = nonSpecInsts.end();
 
-            cprintf("%#x ", curr->inst->readPC());
-        }
+    cprintf("Non speculative list: ");
 
-        cprintf("\n");
+    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>::dumpLists()
+InstructionQueue<Impl>::dumpInsts()
 {
-    cprintf("Ready integer list size: %i\n", readyIntInsts.size());
+    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());
 
-    cprintf("Ready float list size: %i\n", readyFloatInsts.size());
+            if ((*inst_list_it)->isMemRef()) {
+                cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
+            }
 
-    cprintf("Ready branch list size: %i\n", readyBranchInsts.size());
+            cprintf("\n");
 
-    cprintf("Ready misc list size: %i\n", readyMiscInsts.size());
+            inst_list_it++;
+            ++num;
+        }
+    }
 
-    cprintf("Squashed list size: %i\n", squashedInsts.size());
+    cprintf("Insts to Execute list:\n");
 
-    cprintf("Non speculative list size: %i\n", nonSpecInsts.size());
+    int num = 0;
+    int valid_num = 0;
+    ListIt inst_list_it = instsToExecute.begin();
 
-    non_spec_it_t non_spec_it = nonSpecInsts.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("Non speculative list: ");
+        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());
 
-    while (non_spec_it != nonSpecInsts.end()) {
-        cprintf("%#x ", (*non_spec_it).second->readPC());
-        ++non_spec_it;
-    }
+        if ((*inst_list_it)->isMemRef()) {
+            cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone);
+        }
 
-    cprintf("\n");
+        cprintf("\n");
 
+        inst_list_it++;
+        ++num;
+    }
 }