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Diffstat (limited to 'src/cpu/o3/inst_queue.hh')
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diff --git a/src/cpu/o3/inst_queue.hh b/src/cpu/o3/inst_queue.hh new file mode 100644 index 000000000..60a713020 --- /dev/null +++ b/src/cpu/o3/inst_queue.hh @@ -0,0 +1,503 @@ +/* + * Copyright (c) 2004-2006 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Kevin Lim + */ + +#ifndef __CPU_O3_INST_QUEUE_HH__ +#define __CPU_O3_INST_QUEUE_HH__ + +#include <list> +#include <map> +#include <queue> +#include <vector> + +#include "base/statistics.hh" +#include "base/timebuf.hh" +#include "cpu/inst_seq.hh" +#include "cpu/o3/dep_graph.hh" +#include "cpu/op_class.hh" +#include "sim/host.hh" + +class FUPool; +class MemInterface; + +/** + * A standard instruction queue class. It holds ready instructions, in + * order, in seperate priority queues to facilitate the scheduling of + * instructions. The IQ uses a separate linked list to track dependencies. + * Similar to the rename map and the free list, it expects that + * floating point registers have their indices start after the integer + * registers (ie with 96 int and 96 fp registers, regs 0-95 are integer + * and 96-191 are fp). This remains true even for both logical and + * physical register indices. The IQ depends on the memory dependence unit to + * track when memory operations are ready in terms of ordering; register + * dependencies are tracked normally. Right now the IQ also handles the + * execution timing; this is mainly to allow back-to-back scheduling without + * requiring IEW to be able to peek into the IQ. At the end of the execution + * latency, the instruction is put into the queue to execute, where it will + * have the execute() function called on it. + * @todo: Make IQ able to handle multiple FU pools. + */ +template <class Impl> +class InstructionQueue +{ + public: + //Typedefs from the Impl. + typedef typename Impl::FullCPU FullCPU; + typedef typename Impl::DynInstPtr DynInstPtr; + typedef typename Impl::Params Params; + + typedef typename Impl::CPUPol::IEW IEW; + typedef typename Impl::CPUPol::MemDepUnit MemDepUnit; + typedef typename Impl::CPUPol::IssueStruct IssueStruct; + typedef typename Impl::CPUPol::TimeStruct TimeStruct; + + // Typedef of iterator through the list of instructions. + typedef typename std::list<DynInstPtr>::iterator ListIt; + + friend class Impl::FullCPU; + + /** FU completion event class. */ + class FUCompletion : public Event { + private: + /** Executing instruction. */ + DynInstPtr inst; + + /** Index of the FU used for executing. */ + int fuIdx; + + /** Pointer back to the instruction queue. */ + InstructionQueue<Impl> *iqPtr; + + /** Should the FU be added to the list to be freed upon + * completing this event. + */ + bool freeFU; + + public: + /** Construct a FU completion event. */ + FUCompletion(DynInstPtr &_inst, int fu_idx, + InstructionQueue<Impl> *iq_ptr); + + virtual void process(); + virtual const char *description(); + void setFreeFU() { freeFU = true; } + }; + + /** Constructs an IQ. */ + InstructionQueue(Params *params); + + /** Destructs the IQ. */ + ~InstructionQueue(); + + /** Returns the name of the IQ. */ + std::string name() const; + + /** Registers statistics. */ + void regStats(); + + /** Resets all instruction queue state. */ + void resetState(); + + /** Sets CPU pointer. */ + void setCPU(FullCPU *_cpu) { cpu = _cpu; } + + /** Sets active threads list. */ + void setActiveThreads(std::list<unsigned> *at_ptr); + + /** Sets the IEW pointer. */ + void setIEW(IEW *iew_ptr) { iewStage = iew_ptr; } + + /** Sets the timer buffer between issue and execute. */ + void setIssueToExecuteQueue(TimeBuffer<IssueStruct> *i2eQueue); + + /** Sets the global time buffer. */ + void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr); + + /** Switches out the instruction queue. */ + void switchOut(); + + /** Takes over execution from another CPU's thread. */ + void takeOverFrom(); + + /** Returns if the IQ is switched out. */ + bool isSwitchedOut() { return switchedOut; } + + /** Number of entries needed for given amount of threads. */ + int entryAmount(int num_threads); + + /** Resets max entries for all threads. */ + void resetEntries(); + + /** Returns total number of free entries. */ + unsigned numFreeEntries(); + + /** Returns number of free entries for a thread. */ + unsigned numFreeEntries(unsigned tid); + + /** Returns whether or not the IQ is full. */ + bool isFull(); + + /** Returns whether or not the IQ is full for a specific thread. */ + bool isFull(unsigned tid); + + /** Returns if there are any ready instructions in the IQ. */ + bool hasReadyInsts(); + + /** Inserts a new instruction into the IQ. */ + void insert(DynInstPtr &new_inst); + + /** Inserts a new, non-speculative instruction into the IQ. */ + void insertNonSpec(DynInstPtr &new_inst); + + /** Inserts a memory or write barrier into the IQ to make sure + * loads and stores are ordered properly. + */ + void insertBarrier(DynInstPtr &barr_inst); + + /** Returns the oldest scheduled instruction, and removes it from + * the list of instructions waiting to execute. + */ + DynInstPtr getInstToExecute(); + + /** + * Records the instruction as the producer of a register without + * adding it to the rest of the IQ. + */ + void recordProducer(DynInstPtr &inst) + { addToProducers(inst); } + + /** Process FU completion event. */ + void processFUCompletion(DynInstPtr &inst, int fu_idx); + + /** + * Schedules ready instructions, adding the ready ones (oldest first) to + * the queue to execute. + */ + void scheduleReadyInsts(); + + /** Schedules a single specific non-speculative instruction. */ + void scheduleNonSpec(const InstSeqNum &inst); + + /** + * Commits all instructions up to and including the given sequence number, + * for a specific thread. + */ + void commit(const InstSeqNum &inst, unsigned tid = 0); + + /** Wakes all dependents of a completed instruction. */ + int wakeDependents(DynInstPtr &completed_inst); + + /** Adds a ready memory instruction to the ready list. */ + void addReadyMemInst(DynInstPtr &ready_inst); + + /** + * Reschedules a memory instruction. It will be ready to issue once + * replayMemInst() is called. + */ + void rescheduleMemInst(DynInstPtr &resched_inst); + + /** Replays a memory instruction. It must be rescheduled first. */ + void replayMemInst(DynInstPtr &replay_inst); + + /** Completes a memory operation. */ + void completeMemInst(DynInstPtr &completed_inst); + + /** Indicates an ordering violation between a store and a load. */ + void violation(DynInstPtr &store, DynInstPtr &faulting_load); + + /** + * Squashes instructions for a thread. Squashing information is obtained + * from the time buffer. + */ + void squash(unsigned tid); + + /** Returns the number of used entries for a thread. */ + unsigned getCount(unsigned tid) { return count[tid]; }; + + /** Debug function to print all instructions. */ + void printInsts(); + + private: + /** Does the actual squashing. */ + void doSquash(unsigned tid); + + ///////////////////////// + // Various pointers + ///////////////////////// + + /** Pointer to the CPU. */ + FullCPU *cpu; + + /** Cache interface. */ + MemInterface *dcacheInterface; + + /** Pointer to IEW stage. */ + IEW *iewStage; + + /** The memory dependence unit, which tracks/predicts memory dependences + * between instructions. + */ + MemDepUnit memDepUnit[Impl::MaxThreads]; + + /** The queue to the execute stage. Issued instructions will be written + * into it. + */ + TimeBuffer<IssueStruct> *issueToExecuteQueue; + + /** The backwards time buffer. */ + TimeBuffer<TimeStruct> *timeBuffer; + + /** Wire to read information from timebuffer. */ + typename TimeBuffer<TimeStruct>::wire fromCommit; + + /** Function unit pool. */ + FUPool *fuPool; + + ////////////////////////////////////// + // Instruction lists, ready queues, and ordering + ////////////////////////////////////// + + /** List of all the instructions in the IQ (some of which may be issued). */ + std::list<DynInstPtr> instList[Impl::MaxThreads]; + + /** List of instructions that are ready to be executed. */ + std::list<DynInstPtr> instsToExecute; + + /** + * Struct for comparing entries to be added to the priority queue. + * This gives reverse ordering to the instructions in terms of + * sequence numbers: the instructions with smaller sequence + * numbers (and hence are older) will be at the top of the + * priority queue. + */ + struct pqCompare { + bool operator() (const DynInstPtr &lhs, const DynInstPtr &rhs) const + { + return lhs->seqNum > rhs->seqNum; + } + }; + + typedef std::priority_queue<DynInstPtr, std::vector<DynInstPtr>, pqCompare> + ReadyInstQueue; + + /** List of ready instructions, per op class. They are separated by op + * class to allow for easy mapping to FUs. + */ + ReadyInstQueue readyInsts[Num_OpClasses]; + + /** List of non-speculative instructions that will be scheduled + * once the IQ gets a signal from commit. While it's redundant to + * have the key be a part of the value (the sequence number is stored + * inside of DynInst), when these instructions are woken up only + * the sequence number will be available. Thus it is most efficient to be + * able to search by the sequence number alone. + */ + std::map<InstSeqNum, DynInstPtr> nonSpecInsts; + + typedef typename std::map<InstSeqNum, DynInstPtr>::iterator NonSpecMapIt; + + /** Entry for the list age ordering by op class. */ + struct ListOrderEntry { + OpClass queueType; + InstSeqNum oldestInst; + }; + + /** List that contains the age order of the oldest instruction of each + * ready queue. Used to select the oldest instruction available + * among op classes. + * @todo: Might be better to just move these entries around instead + * of creating new ones every time the position changes due to an + * instruction issuing. Not sure std::list supports this. + */ + std::list<ListOrderEntry> listOrder; + + typedef typename std::list<ListOrderEntry>::iterator ListOrderIt; + + /** Tracks if each ready queue is on the age order list. */ + bool queueOnList[Num_OpClasses]; + + /** Iterators of each ready queue. Points to their spot in the age order + * list. + */ + ListOrderIt readyIt[Num_OpClasses]; + + /** Add an op class to the age order list. */ + void addToOrderList(OpClass op_class); + + /** + * Called when the oldest instruction has been removed from a ready queue; + * this places that ready queue into the proper spot in the age order list. + */ + void moveToYoungerInst(ListOrderIt age_order_it); + + DependencyGraph<DynInstPtr> dependGraph; + + ////////////////////////////////////// + // Various parameters + ////////////////////////////////////// + + /** IQ Resource Sharing Policy */ + enum IQPolicy { + Dynamic, + Partitioned, + Threshold + }; + + /** IQ sharing policy for SMT. */ + IQPolicy iqPolicy; + + /** Number of Total Threads*/ + unsigned numThreads; + + /** Pointer to list of active threads. */ + std::list<unsigned> *activeThreads; + + /** Per Thread IQ count */ + unsigned count[Impl::MaxThreads]; + + /** Max IQ Entries Per Thread */ + unsigned maxEntries[Impl::MaxThreads]; + + /** Number of free IQ entries left. */ + unsigned freeEntries; + + /** The number of entries in the instruction queue. */ + unsigned numEntries; + + /** The total number of instructions that can be issued in one cycle. */ + unsigned totalWidth; + + /** The number of physical registers in the CPU. */ + unsigned numPhysRegs; + + /** The number of physical integer registers in the CPU. */ + unsigned numPhysIntRegs; + + /** The number of floating point registers in the CPU. */ + unsigned numPhysFloatRegs; + + /** Delay between commit stage and the IQ. + * @todo: Make there be a distinction between the delays within IEW. + */ + unsigned commitToIEWDelay; + + /** Is the IQ switched out. */ + bool switchedOut; + + /** The sequence number of the squashed instruction. */ + InstSeqNum squashedSeqNum[Impl::MaxThreads]; + + /** A cache of the recently woken registers. It is 1 if the register + * has been woken up recently, and 0 if the register has been added + * to the dependency graph and has not yet received its value. It + * is basically a secondary scoreboard, and should pretty much mirror + * the scoreboard that exists in the rename map. + */ + std::vector<bool> regScoreboard; + + /** Adds an instruction to the dependency graph, as a consumer. */ + bool addToDependents(DynInstPtr &new_inst); + + /** Adds an instruction to the dependency graph, as a producer. */ + void addToProducers(DynInstPtr &new_inst); + + /** Moves an instruction to the ready queue if it is ready. */ + void addIfReady(DynInstPtr &inst); + + /** Debugging function to count how many entries are in the IQ. It does + * a linear walk through the instructions, so do not call this function + * during normal execution. + */ + int countInsts(); + + /** Debugging function to dump all the list sizes, as well as print + * out the list of nonspeculative instructions. Should not be used + * in any other capacity, but it has no harmful sideaffects. + */ + void dumpLists(); + + /** Debugging function to dump out all instructions that are in the + * IQ. + */ + void dumpInsts(); + + /** Stat for number of instructions added. */ + Stats::Scalar<> iqInstsAdded; + /** Stat for number of non-speculative instructions added. */ + Stats::Scalar<> iqNonSpecInstsAdded; + + Stats::Scalar<> iqInstsIssued; + /** Stat for number of integer instructions issued. */ + Stats::Scalar<> iqIntInstsIssued; + /** Stat for number of floating point instructions issued. */ + Stats::Scalar<> iqFloatInstsIssued; + /** Stat for number of branch instructions issued. */ + Stats::Scalar<> iqBranchInstsIssued; + /** Stat for number of memory instructions issued. */ + Stats::Scalar<> iqMemInstsIssued; + /** Stat for number of miscellaneous instructions issued. */ + Stats::Scalar<> iqMiscInstsIssued; + /** Stat for number of squashed instructions that were ready to issue. */ + Stats::Scalar<> iqSquashedInstsIssued; + /** Stat for number of squashed instructions examined when squashing. */ + Stats::Scalar<> iqSquashedInstsExamined; + /** Stat for number of squashed instruction operands examined when + * squashing. + */ + Stats::Scalar<> iqSquashedOperandsExamined; + /** Stat for number of non-speculative instructions removed due to a squash. + */ + Stats::Scalar<> iqSquashedNonSpecRemoved; + + /** Distribution of number of instructions in the queue. */ + Stats::VectorDistribution<> queueResDist; + /** Distribution of the number of instructions issued. */ + Stats::Distribution<> numIssuedDist; + /** Distribution of the cycles it takes to issue an instruction. */ + Stats::VectorDistribution<> issueDelayDist; + + /** Number of times an instruction could not be issued because a + * FU was busy. + */ + Stats::Vector<> statFuBusy; +// Stats::Vector<> dist_unissued; + /** Stat for total number issued for each instruction type. */ + Stats::Vector2d<> statIssuedInstType; + + /** Number of instructions issued per cycle. */ + Stats::Formula issueRate; +// Stats::Formula issue_stores; +// Stats::Formula issue_op_rate; + /** Number of times the FU was busy. */ + Stats::Vector<> fuBusy; + /** Number of times the FU was busy per instruction issued. */ + Stats::Formula fuBusyRate; +}; + +#endif //__CPU_O3_INST_QUEUE_HH__ |