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Diffstat (limited to 'src/cpu/o3/commit_impl.hh')
| -rw-r--r-- | src/cpu/o3/commit_impl.hh | 1307 |
1 files changed, 1307 insertions, 0 deletions
diff --git a/src/cpu/o3/commit_impl.hh b/src/cpu/o3/commit_impl.hh new file mode 100644 index 000000000..346a8bc1c --- /dev/null +++ b/src/cpu/o3/commit_impl.hh @@ -0,0 +1,1307 @@ +/* + * 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 <algorithm> +#include <string> + +#include "base/loader/symtab.hh" +#include "base/timebuf.hh" +#include "cpu/checker/cpu.hh" +#include "cpu/exetrace.hh" +#include "cpu/o3/commit.hh" +#include "cpu/o3/thread_state.hh" + +using namespace std; + +template <class Impl> +DefaultCommit<Impl>::TrapEvent::TrapEvent(DefaultCommit<Impl> *_commit, + unsigned _tid) + : Event(&mainEventQueue, CPU_Tick_Pri), commit(_commit), tid(_tid) +{ + this->setFlags(Event::AutoDelete); +} + +template <class Impl> +void +DefaultCommit<Impl>::TrapEvent::process() +{ + // This will get reset by commit if it was switched out at the + // time of this event processing. + commit->trapSquash[tid] = true; +} + +template <class Impl> +const char * +DefaultCommit<Impl>::TrapEvent::description() +{ + return "Trap event"; +} + +template <class Impl> +DefaultCommit<Impl>::DefaultCommit(Params *params) + : dcacheInterface(params->dcacheInterface), + squashCounter(0), + iewToCommitDelay(params->iewToCommitDelay), + commitToIEWDelay(params->commitToIEWDelay), + renameToROBDelay(params->renameToROBDelay), + fetchToCommitDelay(params->commitToFetchDelay), + renameWidth(params->renameWidth), + iewWidth(params->executeWidth), + commitWidth(params->commitWidth), + numThreads(params->numberOfThreads), + switchedOut(false), + trapLatency(params->trapLatency), + fetchTrapLatency(params->fetchTrapLatency) +{ + _status = Active; + _nextStatus = Inactive; + string policy = params->smtCommitPolicy; + + //Convert string to lowercase + std::transform(policy.begin(), policy.end(), policy.begin(), + (int(*)(int)) tolower); + + //Assign commit policy + if (policy == "aggressive"){ + commitPolicy = Aggressive; + + DPRINTF(Commit,"Commit Policy set to Aggressive."); + } else if (policy == "roundrobin"){ + commitPolicy = RoundRobin; + + //Set-Up Priority List + for (int tid=0; tid < numThreads; tid++) { + priority_list.push_back(tid); + } + + DPRINTF(Commit,"Commit Policy set to Round Robin."); + } else if (policy == "oldestready"){ + commitPolicy = OldestReady; + + DPRINTF(Commit,"Commit Policy set to Oldest Ready."); + } else { + assert(0 && "Invalid SMT Commit Policy. Options Are: {Aggressive," + "RoundRobin,OldestReady}"); + } + + for (int i=0; i < numThreads; i++) { + commitStatus[i] = Idle; + changedROBNumEntries[i] = false; + trapSquash[i] = false; + xcSquash[i] = false; + } + + fetchFaultTick = 0; + fetchTrapWait = 0; +} + +template <class Impl> +std::string +DefaultCommit<Impl>::name() const +{ + return cpu->name() + ".commit"; +} + +template <class Impl> +void +DefaultCommit<Impl>::regStats() +{ + using namespace Stats; + commitCommittedInsts + .name(name() + ".commitCommittedInsts") + .desc("The number of committed instructions") + .prereq(commitCommittedInsts); + commitSquashedInsts + .name(name() + ".commitSquashedInsts") + .desc("The number of squashed insts skipped by commit") + .prereq(commitSquashedInsts); + commitSquashEvents + .name(name() + ".commitSquashEvents") + .desc("The number of times commit is told to squash") + .prereq(commitSquashEvents); + commitNonSpecStalls + .name(name() + ".commitNonSpecStalls") + .desc("The number of times commit has been forced to stall to " + "communicate backwards") + .prereq(commitNonSpecStalls); + branchMispredicts + .name(name() + ".branchMispredicts") + .desc("The number of times a branch was mispredicted") + .prereq(branchMispredicts); + numCommittedDist + .init(0,commitWidth,1) + .name(name() + ".COM:committed_per_cycle") + .desc("Number of insts commited each cycle") + .flags(Stats::pdf) + ; + + statComInst + .init(cpu->number_of_threads) + .name(name() + ".COM:count") + .desc("Number of instructions committed") + .flags(total) + ; + + statComSwp + .init(cpu->number_of_threads) + .name(name() + ".COM:swp_count") + .desc("Number of s/w prefetches committed") + .flags(total) + ; + + statComRefs + .init(cpu->number_of_threads) + .name(name() + ".COM:refs") + .desc("Number of memory references committed") + .flags(total) + ; + + statComLoads + .init(cpu->number_of_threads) + .name(name() + ".COM:loads") + .desc("Number of loads committed") + .flags(total) + ; + + statComMembars + .init(cpu->number_of_threads) + .name(name() + ".COM:membars") + .desc("Number of memory barriers committed") + .flags(total) + ; + + statComBranches + .init(cpu->number_of_threads) + .name(name() + ".COM:branches") + .desc("Number of branches committed") + .flags(total) + ; + + // + // Commit-Eligible instructions... + // + // -> The number of instructions eligible to commit in those + // cycles where we reached our commit BW limit (less the number + // actually committed) + // + // -> The average value is computed over ALL CYCLES... not just + // the BW limited cycles + // + // -> The standard deviation is computed only over cycles where + // we reached the BW limit + // + commitEligible + .init(cpu->number_of_threads) + .name(name() + ".COM:bw_limited") + .desc("number of insts not committed due to BW limits") + .flags(total) + ; + + commitEligibleSamples + .name(name() + ".COM:bw_lim_events") + .desc("number cycles where commit BW limit reached") + ; +} + +template <class Impl> +void +DefaultCommit<Impl>::setCPU(FullCPU *cpu_ptr) +{ + DPRINTF(Commit, "Commit: Setting CPU pointer.\n"); + cpu = cpu_ptr; + + // Commit must broadcast the number of free entries it has at the start of + // the simulation, so it starts as active. + cpu->activateStage(FullCPU::CommitIdx); + + trapLatency = cpu->cycles(trapLatency); + fetchTrapLatency = cpu->cycles(fetchTrapLatency); +} + +template <class Impl> +void +DefaultCommit<Impl>::setThreads(vector<Thread *> &threads) +{ + thread = threads; +} + +template <class Impl> +void +DefaultCommit<Impl>::setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr) +{ + DPRINTF(Commit, "Commit: Setting time buffer pointer.\n"); + timeBuffer = tb_ptr; + + // Setup wire to send information back to IEW. + toIEW = timeBuffer->getWire(0); + + // Setup wire to read data from IEW (for the ROB). + robInfoFromIEW = timeBuffer->getWire(-iewToCommitDelay); +} + +template <class Impl> +void +DefaultCommit<Impl>::setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr) +{ + DPRINTF(Commit, "Commit: Setting fetch queue pointer.\n"); + fetchQueue = fq_ptr; + + // Setup wire to get instructions from rename (for the ROB). + fromFetch = fetchQueue->getWire(-fetchToCommitDelay); +} + +template <class Impl> +void +DefaultCommit<Impl>::setRenameQueue(TimeBuffer<RenameStruct> *rq_ptr) +{ + DPRINTF(Commit, "Commit: Setting rename queue pointer.\n"); + renameQueue = rq_ptr; + + // Setup wire to get instructions from rename (for the ROB). + fromRename = renameQueue->getWire(-renameToROBDelay); +} + +template <class Impl> +void +DefaultCommit<Impl>::setIEWQueue(TimeBuffer<IEWStruct> *iq_ptr) +{ + DPRINTF(Commit, "Commit: Setting IEW queue pointer.\n"); + iewQueue = iq_ptr; + + // Setup wire to get instructions from IEW. + fromIEW = iewQueue->getWire(-iewToCommitDelay); +} + +template <class Impl> +void +DefaultCommit<Impl>::setFetchStage(Fetch *fetch_stage) +{ + fetchStage = fetch_stage; +} + +template <class Impl> +void +DefaultCommit<Impl>::setIEWStage(IEW *iew_stage) +{ + iewStage = iew_stage; +} + +template<class Impl> +void +DefaultCommit<Impl>::setActiveThreads(list<unsigned> *at_ptr) +{ + DPRINTF(Commit, "Commit: Setting active threads list pointer.\n"); + activeThreads = at_ptr; +} + +template <class Impl> +void +DefaultCommit<Impl>::setRenameMap(RenameMap rm_ptr[]) +{ + DPRINTF(Commit, "Setting rename map pointers.\n"); + + for (int i=0; i < numThreads; i++) { + renameMap[i] = &rm_ptr[i]; + } +} + +template <class Impl> +void +DefaultCommit<Impl>::setROB(ROB *rob_ptr) +{ + DPRINTF(Commit, "Commit: Setting ROB pointer.\n"); + rob = rob_ptr; +} + +template <class Impl> +void +DefaultCommit<Impl>::initStage() +{ + rob->setActiveThreads(activeThreads); + rob->resetEntries(); + + // Broadcast the number of free entries. + for (int i=0; i < numThreads; i++) { + toIEW->commitInfo[i].usedROB = true; + toIEW->commitInfo[i].freeROBEntries = rob->numFreeEntries(i); + } + + cpu->activityThisCycle(); +} + +template <class Impl> +void +DefaultCommit<Impl>::switchOut() +{ + switchPending = true; +} + +template <class Impl> +void +DefaultCommit<Impl>::doSwitchOut() +{ + switchedOut = true; + switchPending = false; + rob->switchOut(); +} + +template <class Impl> +void +DefaultCommit<Impl>::takeOverFrom() +{ + switchedOut = false; + _status = Active; + _nextStatus = Inactive; + for (int i=0; i < numThreads; i++) { + commitStatus[i] = Idle; + changedROBNumEntries[i] = false; + trapSquash[i] = false; + xcSquash[i] = false; + } + squashCounter = 0; + rob->takeOverFrom(); +} + +template <class Impl> +void +DefaultCommit<Impl>::updateStatus() +{ + // reset ROB changed variable + list<unsigned>::iterator threads = (*activeThreads).begin(); + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + changedROBNumEntries[tid] = false; + + // Also check if any of the threads has a trap pending + if (commitStatus[tid] == TrapPending || + commitStatus[tid] == FetchTrapPending) { + _nextStatus = Active; + } + } + + if (_nextStatus == Inactive && _status == Active) { + DPRINTF(Activity, "Deactivating stage.\n"); + cpu->deactivateStage(FullCPU::CommitIdx); + } else if (_nextStatus == Active && _status == Inactive) { + DPRINTF(Activity, "Activating stage.\n"); + cpu->activateStage(FullCPU::CommitIdx); + } + + _status = _nextStatus; +} + +template <class Impl> +void +DefaultCommit<Impl>::setNextStatus() +{ + int squashes = 0; + + list<unsigned>::iterator threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (commitStatus[tid] == ROBSquashing) { + squashes++; + } + } + + assert(squashes == squashCounter); + + // If commit is currently squashing, then it will have activity for the + // next cycle. Set its next status as active. + if (squashCounter) { + _nextStatus = Active; + } +} + +template <class Impl> +bool +DefaultCommit<Impl>::changedROBEntries() +{ + list<unsigned>::iterator threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (changedROBNumEntries[tid]) { + return true; + } + } + + return false; +} + +template <class Impl> +unsigned +DefaultCommit<Impl>::numROBFreeEntries(unsigned tid) +{ + return rob->numFreeEntries(tid); +} + +template <class Impl> +void +DefaultCommit<Impl>::generateTrapEvent(unsigned tid) +{ + DPRINTF(Commit, "Generating trap event for [tid:%i]\n", tid); + + TrapEvent *trap = new TrapEvent(this, tid); + + trap->schedule(curTick + trapLatency); + + thread[tid]->trapPending = true; +} + +template <class Impl> +void +DefaultCommit<Impl>::generateXCEvent(unsigned tid) +{ + DPRINTF(Commit, "Generating XC squash event for [tid:%i]\n", tid); + + xcSquash[tid] = true; +} + +template <class Impl> +void +DefaultCommit<Impl>::squashAll(unsigned tid) +{ + // If we want to include the squashing instruction in the squash, + // then use one older sequence number. + // Hopefully this doesn't mess things up. Basically I want to squash + // all instructions of this thread. + InstSeqNum squashed_inst = rob->isEmpty() ? + 0 : rob->readHeadInst(tid)->seqNum - 1;; + + // All younger instructions will be squashed. Set the sequence + // number as the youngest instruction in the ROB (0 in this case. + // Hopefully nothing breaks.) + youngestSeqNum[tid] = 0; + + rob->squash(squashed_inst, tid); + changedROBNumEntries[tid] = true; + + // Send back the sequence number of the squashed instruction. + toIEW->commitInfo[tid].doneSeqNum = squashed_inst; + + // Send back the squash signal to tell stages that they should + // squash. + toIEW->commitInfo[tid].squash = true; + + // Send back the rob squashing signal so other stages know that + // the ROB is in the process of squashing. + toIEW->commitInfo[tid].robSquashing = true; + + toIEW->commitInfo[tid].branchMispredict = false; + + toIEW->commitInfo[tid].nextPC = PC[tid]; +} + +template <class Impl> +void +DefaultCommit<Impl>::squashFromTrap(unsigned tid) +{ + squashAll(tid); + + DPRINTF(Commit, "Squashing from trap, restarting at PC %#x\n", PC[tid]); + + thread[tid]->trapPending = false; + thread[tid]->inSyscall = false; + + trapSquash[tid] = false; + + commitStatus[tid] = ROBSquashing; + cpu->activityThisCycle(); + + ++squashCounter; +} + +template <class Impl> +void +DefaultCommit<Impl>::squashFromXC(unsigned tid) +{ + squashAll(tid); + + DPRINTF(Commit, "Squashing from XC, restarting at PC %#x\n", PC[tid]); + + thread[tid]->inSyscall = false; + assert(!thread[tid]->trapPending); + + commitStatus[tid] = ROBSquashing; + cpu->activityThisCycle(); + + xcSquash[tid] = false; + + ++squashCounter; +} + +template <class Impl> +void +DefaultCommit<Impl>::tick() +{ + wroteToTimeBuffer = false; + _nextStatus = Inactive; + + if (switchPending && rob->isEmpty() && !iewStage->hasStoresToWB()) { + cpu->signalSwitched(); + return; + } + + list<unsigned>::iterator threads = (*activeThreads).begin(); + + // Check if any of the threads are done squashing. Change the + // status if they are done. + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (commitStatus[tid] == ROBSquashing) { + + if (rob->isDoneSquashing(tid)) { + commitStatus[tid] = Running; + --squashCounter; + } else { + DPRINTF(Commit,"[tid:%u]: Still Squashing, cannot commit any" + "insts this cycle.\n", tid); + } + } + } + + commit(); + + markCompletedInsts(); + + threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (!rob->isEmpty(tid) && rob->readHeadInst(tid)->readyToCommit()) { + // The ROB has more instructions it can commit. Its next status + // will be active. + _nextStatus = Active; + + DynInstPtr inst = rob->readHeadInst(tid); + + DPRINTF(Commit,"[tid:%i]: Instruction [sn:%lli] PC %#x is head of" + " ROB and ready to commit\n", + tid, inst->seqNum, inst->readPC()); + + } else if (!rob->isEmpty(tid)) { + DynInstPtr inst = rob->readHeadInst(tid); + + DPRINTF(Commit,"[tid:%i]: Can't commit, Instruction [sn:%lli] PC " + "%#x is head of ROB and not ready\n", + tid, inst->seqNum, inst->readPC()); + } + + DPRINTF(Commit, "[tid:%i]: ROB has %d insts & %d free entries.\n", + tid, rob->countInsts(tid), rob->numFreeEntries(tid)); + } + + + if (wroteToTimeBuffer) { + DPRINTF(Activity, "Activity This Cycle.\n"); + cpu->activityThisCycle(); + } + + updateStatus(); +} + +template <class Impl> +void +DefaultCommit<Impl>::commit() +{ + + ////////////////////////////////////// + // Check for interrupts + ////////////////////////////////////// + +#if FULL_SYSTEM + // Process interrupts if interrupts are enabled, not in PAL mode, + // and no other traps or external squashes are currently pending. + // @todo: Allow other threads to handle interrupts. + if (cpu->checkInterrupts && + cpu->check_interrupts() && + !cpu->inPalMode(readPC()) && + !trapSquash[0] && + !xcSquash[0]) { + // Tell fetch that there is an interrupt pending. This will + // make fetch wait until it sees a non PAL-mode PC, at which + // point it stops fetching instructions. + toIEW->commitInfo[0].interruptPending = true; + + // Wait until the ROB is empty and all stores have drained in + // order to enter the interrupt. + if (rob->isEmpty() && !iewStage->hasStoresToWB()) { + // Not sure which thread should be the one to interrupt. For now + // always do thread 0. + assert(!thread[0]->inSyscall); + thread[0]->inSyscall = true; + + // CPU will handle implementation of the interrupt. + cpu->processInterrupts(); + + // Now squash or record that I need to squash this cycle. + commitStatus[0] = TrapPending; + + // Exit state update mode to avoid accidental updating. + thread[0]->inSyscall = false; + + // Generate trap squash event. + generateTrapEvent(0); + + toIEW->commitInfo[0].clearInterrupt = true; + + DPRINTF(Commit, "Interrupt detected.\n"); + } else { + DPRINTF(Commit, "Interrupt pending, waiting for ROB to empty.\n"); + } + } +#endif // FULL_SYSTEM + + //////////////////////////////////// + // Check for any possible squashes, handle them first + //////////////////////////////////// + + list<unsigned>::iterator threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (fromFetch->fetchFault && commitStatus[0] != TrapPending) { + // Record the fault. Wait until it's empty in the ROB. + // Then handle the trap. Ignore it if there's already a + // trap pending as fetch will be redirected. + fetchFault = fromFetch->fetchFault; + fetchFaultTick = curTick + fetchTrapLatency; + commitStatus[0] = FetchTrapPending; + DPRINTF(Commit, "Fault from fetch recorded. Will trap if the " + "ROB empties without squashing the fault.\n"); + fetchTrapWait = 0; + } + + // Fetch may tell commit to clear the trap if it's been squashed. + if (fromFetch->clearFetchFault) { + DPRINTF(Commit, "Received clear fetch fault signal\n"); + fetchTrapWait = 0; + if (commitStatus[0] == FetchTrapPending) { + DPRINTF(Commit, "Clearing fault from fetch\n"); + commitStatus[0] = Running; + } + } + + // Not sure which one takes priority. I think if we have + // both, that's a bad sign. + if (trapSquash[tid] == true) { + assert(!xcSquash[tid]); + squashFromTrap(tid); + } else if (xcSquash[tid] == true) { + squashFromXC(tid); + } + + // Squashed sequence number must be older than youngest valid + // instruction in the ROB. This prevents squashes from younger + // instructions overriding squashes from older instructions. + if (fromIEW->squash[tid] && + commitStatus[tid] != TrapPending && + fromIEW->squashedSeqNum[tid] <= youngestSeqNum[tid]) { + + DPRINTF(Commit, "[tid:%i]: Squashing due to PC %#x [sn:%i]\n", + tid, + fromIEW->mispredPC[tid], + fromIEW->squashedSeqNum[tid]); + + DPRINTF(Commit, "[tid:%i]: Redirecting to PC %#x\n", + tid, + fromIEW->nextPC[tid]); + + commitStatus[tid] = ROBSquashing; + + ++squashCounter; + + // If we want to include the squashing instruction in the squash, + // then use one older sequence number. + InstSeqNum squashed_inst = fromIEW->squashedSeqNum[tid]; + + if (fromIEW->includeSquashInst[tid] == true) + squashed_inst--; + + // All younger instructions will be squashed. Set the sequence + // number as the youngest instruction in the ROB. + youngestSeqNum[tid] = squashed_inst; + + rob->squash(squashed_inst, tid); + changedROBNumEntries[tid] = true; + + toIEW->commitInfo[tid].doneSeqNum = squashed_inst; + + toIEW->commitInfo[tid].squash = true; + + // Send back the rob squashing signal so other stages know that + // the ROB is in the process of squashing. + toIEW->commitInfo[tid].robSquashing = true; + + toIEW->commitInfo[tid].branchMispredict = + fromIEW->branchMispredict[tid]; + + toIEW->commitInfo[tid].branchTaken = + fromIEW->branchTaken[tid]; + + toIEW->commitInfo[tid].nextPC = fromIEW->nextPC[tid]; + + toIEW->commitInfo[tid].mispredPC = fromIEW->mispredPC[tid]; + + if (toIEW->commitInfo[tid].branchMispredict) { + ++branchMispredicts; + } + } + + } + + setNextStatus(); + + if (squashCounter != numThreads) { + // If we're not currently squashing, then get instructions. + getInsts(); + + // Try to commit any instructions. + commitInsts(); + } + + //Check for any activity + threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (changedROBNumEntries[tid]) { + toIEW->commitInfo[tid].usedROB = true; + toIEW->commitInfo[tid].freeROBEntries = rob->numFreeEntries(tid); + + if (rob->isEmpty(tid)) { + toIEW->commitInfo[tid].emptyROB = true; + } + + wroteToTimeBuffer = true; + changedROBNumEntries[tid] = false; + } + } +} + +template <class Impl> +void +DefaultCommit<Impl>::commitInsts() +{ + //////////////////////////////////// + // Handle commit + // Note that commit will be handled prior to putting new + // instructions in the ROB so that the ROB only tries to commit + // instructions it has in this current cycle, and not instructions + // it is writing in during this cycle. Can't commit and squash + // things at the same time... + //////////////////////////////////// + + DPRINTF(Commit, "Trying to commit instructions in the ROB.\n"); + + unsigned num_committed = 0; + + DynInstPtr head_inst; + + // Commit as many instructions as possible until the commit bandwidth + // limit is reached, or it becomes impossible to commit any more. + while (num_committed < commitWidth) { + int commit_thread = getCommittingThread(); + + if (commit_thread == -1 || !rob->isHeadReady(commit_thread)) + break; + + head_inst = rob->readHeadInst(commit_thread); + + int tid = head_inst->threadNumber; + + assert(tid == commit_thread); + + DPRINTF(Commit, "Trying to commit head instruction, [sn:%i] [tid:%i]\n", + head_inst->seqNum, tid); + + // If the head instruction is squashed, it is ready to retire + // (be removed from the ROB) at any time. + if (head_inst->isSquashed()) { + + DPRINTF(Commit, "Retiring squashed instruction from " + "ROB.\n"); + + rob->retireHead(commit_thread); + + ++commitSquashedInsts; + + // Record that the number of ROB entries has changed. + changedROBNumEntries[tid] = true; + } else { + PC[tid] = head_inst->readPC(); + nextPC[tid] = head_inst->readNextPC(); + + // Increment the total number of non-speculative instructions + // executed. + // Hack for now: it really shouldn't happen until after the + // commit is deemed to be successful, but this count is needed + // for syscalls. + thread[tid]->funcExeInst++; + + // Try to commit the head instruction. + bool commit_success = commitHead(head_inst, num_committed); + + if (commit_success) { + ++num_committed; + + changedROBNumEntries[tid] = true; + + // Set the doneSeqNum to the youngest committed instruction. + toIEW->commitInfo[tid].doneSeqNum = head_inst->seqNum; + + ++commitCommittedInsts; + + // To match the old model, don't count nops and instruction + // prefetches towards the total commit count. + if (!head_inst->isNop() && !head_inst->isInstPrefetch()) { + cpu->instDone(tid); + } + + PC[tid] = nextPC[tid]; + nextPC[tid] = nextPC[tid] + sizeof(TheISA::MachInst); +#if FULL_SYSTEM + int count = 0; + Addr oldpc; + do { + // Debug statement. Checks to make sure we're not + // currently updating state while handling PC events. + if (count == 0) + assert(!thread[tid]->inSyscall && + !thread[tid]->trapPending); + oldpc = PC[tid]; + cpu->system->pcEventQueue.service( + thread[tid]->getXCProxy()); + count++; + } while (oldpc != PC[tid]); + if (count > 1) { + DPRINTF(Commit, "PC skip function event, stopping commit\n"); + break; + } +#endif + } else { + DPRINTF(Commit, "Unable to commit head instruction PC:%#x " + "[tid:%i] [sn:%i].\n", + head_inst->readPC(), tid ,head_inst->seqNum); + break; + } + } + } + + DPRINTF(CommitRate, "%i\n", num_committed); + numCommittedDist.sample(num_committed); + + if (num_committed == commitWidth) { + commitEligible[0]++; + } +} + +template <class Impl> +bool +DefaultCommit<Impl>::commitHead(DynInstPtr &head_inst, unsigned inst_num) +{ + assert(head_inst); + + int tid = head_inst->threadNumber; + + // If the instruction is not executed yet, then it will need extra + // handling. Signal backwards that it should be executed. + if (!head_inst->isExecuted()) { + // Keep this number correct. We have not yet actually executed + // and committed this instruction. + thread[tid]->funcExeInst--; + + head_inst->reachedCommit = true; + + if (head_inst->isNonSpeculative() || + head_inst->isMemBarrier() || + head_inst->isWriteBarrier()) { + + DPRINTF(Commit, "Encountered a barrier or non-speculative " + "instruction [sn:%lli] at the head of the ROB, PC %#x.\n", + head_inst->seqNum, head_inst->readPC()); + +#if !FULL_SYSTEM + // Hack to make sure syscalls/memory barriers/quiesces + // aren't executed until all stores write back their data. + // This direct communication shouldn't be used for + // anything other than this. + if (inst_num > 0 || iewStage->hasStoresToWB()) +#else + if ((head_inst->isMemBarrier() || head_inst->isWriteBarrier() || + head_inst->isQuiesce()) && + iewStage->hasStoresToWB()) +#endif + { + DPRINTF(Commit, "Waiting for all stores to writeback.\n"); + return false; + } + + toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum; + + // Change the instruction so it won't try to commit again until + // it is executed. + head_inst->clearCanCommit(); + + ++commitNonSpecStalls; + + return false; + } else if (head_inst->isLoad()) { + DPRINTF(Commit, "[sn:%lli]: Uncached load, PC %#x.\n", + head_inst->seqNum, head_inst->readPC()); + + // Send back the non-speculative instruction's sequence + // number. Tell the lsq to re-execute the load. + toIEW->commitInfo[tid].nonSpecSeqNum = head_inst->seqNum; + toIEW->commitInfo[tid].uncached = true; + toIEW->commitInfo[tid].uncachedLoad = head_inst; + + head_inst->clearCanCommit(); + + return false; + } else { + panic("Trying to commit un-executed instruction " + "of unknown type!\n"); + } + } + + if (head_inst->isThreadSync()) { + // Not handled for now. + panic("Thread sync instructions are not handled yet.\n"); + } + + // Stores mark themselves as completed. + if (!head_inst->isStore()) { + head_inst->setCompleted(); + } + + // Use checker prior to updating anything due to traps or PC + // based events. + if (cpu->checker) { + cpu->checker->tick(head_inst); + } + + // Check if the instruction caused a fault. If so, trap. + Fault inst_fault = head_inst->getFault(); + + if (inst_fault != NoFault) { + head_inst->setCompleted(); +#if FULL_SYSTEM + DPRINTF(Commit, "Inst [sn:%lli] PC %#x has a fault\n", + head_inst->seqNum, head_inst->readPC()); + + if (iewStage->hasStoresToWB() || inst_num > 0) { + DPRINTF(Commit, "Stores outstanding, fault must wait.\n"); + return false; + } + + if (cpu->checker && head_inst->isStore()) { + cpu->checker->tick(head_inst); + } + + assert(!thread[tid]->inSyscall); + + // Mark that we're in state update mode so that the trap's + // execution doesn't generate extra squashes. + thread[tid]->inSyscall = true; + + // DTB will sometimes need the machine instruction for when + // faults happen. So we will set it here, prior to the DTB + // possibly needing it for its fault. + thread[tid]->setInst( + static_cast<TheISA::MachInst>(head_inst->staticInst->machInst)); + + // Execute the trap. Although it's slightly unrealistic in + // terms of timing (as it doesn't wait for the full timing of + // the trap event to complete before updating state), it's + // needed to update the state as soon as possible. This + // prevents external agents from changing any specific state + // that the trap need. + cpu->trap(inst_fault, tid); + + // Exit state update mode to avoid accidental updating. + thread[tid]->inSyscall = false; + + commitStatus[tid] = TrapPending; + + // Generate trap squash event. + generateTrapEvent(tid); + + return false; +#else // !FULL_SYSTEM + panic("fault (%d) detected @ PC %08p", inst_fault, + head_inst->PC); +#endif // FULL_SYSTEM + } + + updateComInstStats(head_inst); + + if (head_inst->traceData) { + head_inst->traceData->setFetchSeq(head_inst->seqNum); + head_inst->traceData->setCPSeq(thread[tid]->numInst); + head_inst->traceData->finalize(); + head_inst->traceData = NULL; + } + + // Update the commit rename map + for (int i = 0; i < head_inst->numDestRegs(); i++) { + renameMap[tid]->setEntry(head_inst->destRegIdx(i), + head_inst->renamedDestRegIdx(i)); + } + + // Finally clear the head ROB entry. + rob->retireHead(tid); + + // Return true to indicate that we have committed an instruction. + return true; +} + +template <class Impl> +void +DefaultCommit<Impl>::getInsts() +{ + // Read any renamed instructions and place them into the ROB. + int insts_to_process = min((int)renameWidth, fromRename->size); + + for (int inst_num = 0; inst_num < insts_to_process; ++inst_num) + { + DynInstPtr inst = fromRename->insts[inst_num]; + int tid = inst->threadNumber; + + if (!inst->isSquashed() && + commitStatus[tid] != ROBSquashing) { + changedROBNumEntries[tid] = true; + + DPRINTF(Commit, "Inserting PC %#x [sn:%i] [tid:%i] into ROB.\n", + inst->readPC(), inst->seqNum, tid); + + rob->insertInst(inst); + + assert(rob->getThreadEntries(tid) <= rob->getMaxEntries(tid)); + + youngestSeqNum[tid] = inst->seqNum; + } else { + DPRINTF(Commit, "Instruction PC %#x [sn:%i] [tid:%i] was " + "squashed, skipping.\n", + inst->readPC(), inst->seqNum, tid); + } + } +} + +template <class Impl> +void +DefaultCommit<Impl>::markCompletedInsts() +{ + // Grab completed insts out of the IEW instruction queue, and mark + // instructions completed within the ROB. + for (int inst_num = 0; + inst_num < fromIEW->size && fromIEW->insts[inst_num]; + ++inst_num) + { + if (!fromIEW->insts[inst_num]->isSquashed()) { + DPRINTF(Commit, "[tid:%i]: Marking PC %#x, [sn:%lli] ready " + "within ROB.\n", + fromIEW->insts[inst_num]->threadNumber, + fromIEW->insts[inst_num]->readPC(), + fromIEW->insts[inst_num]->seqNum); + + // Mark the instruction as ready to commit. + fromIEW->insts[inst_num]->setCanCommit(); + } + } +} + +template <class Impl> +bool +DefaultCommit<Impl>::robDoneSquashing() +{ + list<unsigned>::iterator threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (!rob->isDoneSquashing(tid)) + return false; + } + + return true; +} + +template <class Impl> +void +DefaultCommit<Impl>::updateComInstStats(DynInstPtr &inst) +{ + unsigned thread = inst->threadNumber; + + // + // Pick off the software prefetches + // +#ifdef TARGET_ALPHA + if (inst->isDataPrefetch()) { + statComSwp[thread]++; + } else { + statComInst[thread]++; + } +#else + statComInst[thread]++; +#endif + + // + // Control Instructions + // + if (inst->isControl()) + statComBranches[thread]++; + + // + // Memory references + // + if (inst->isMemRef()) { + statComRefs[thread]++; + + if (inst->isLoad()) { + statComLoads[thread]++; + } + } + + if (inst->isMemBarrier()) { + statComMembars[thread]++; + } +} + +//////////////////////////////////////// +// // +// SMT COMMIT POLICY MAINTAINED HERE // +// // +//////////////////////////////////////// +template <class Impl> +int +DefaultCommit<Impl>::getCommittingThread() +{ + if (numThreads > 1) { + switch (commitPolicy) { + + case Aggressive: + //If Policy is Aggressive, commit will call + //this function multiple times per + //cycle + return oldestReady(); + + case RoundRobin: + return roundRobin(); + + case OldestReady: + return oldestReady(); + + default: + return -1; + } + } else { + int tid = (*activeThreads).front(); + + if (commitStatus[tid] == Running || + commitStatus[tid] == Idle || + commitStatus[tid] == FetchTrapPending) { + return tid; + } else { + return -1; + } + } +} + +template<class Impl> +int +DefaultCommit<Impl>::roundRobin() +{ + list<unsigned>::iterator pri_iter = priority_list.begin(); + list<unsigned>::iterator end = priority_list.end(); + + while (pri_iter != end) { + unsigned tid = *pri_iter; + + if (commitStatus[tid] == Running || + commitStatus[tid] == Idle) { + + if (rob->isHeadReady(tid)) { + priority_list.erase(pri_iter); + priority_list.push_back(tid); + + return tid; + } + } + + pri_iter++; + } + + return -1; +} + +template<class Impl> +int +DefaultCommit<Impl>::oldestReady() +{ + unsigned oldest = 0; + bool first = true; + + list<unsigned>::iterator threads = (*activeThreads).begin(); + + while (threads != (*activeThreads).end()) { + unsigned tid = *threads++; + + if (!rob->isEmpty(tid) && + (commitStatus[tid] == Running || + commitStatus[tid] == Idle || + commitStatus[tid] == FetchTrapPending)) { + + if (rob->isHeadReady(tid)) { + + DynInstPtr head_inst = rob->readHeadInst(tid); + + if (first) { + oldest = tid; + first = false; + } else if (head_inst->seqNum < oldest) { + oldest = tid; + } + } + } + } + + if (!first) { + return oldest; + } else { + return -1; + } +} |