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Diffstat (limited to 'cpu/ozone/lw_back_end_impl.hh')
| -rw-r--r-- | cpu/ozone/lw_back_end_impl.hh | 1693 |
1 files changed, 1693 insertions, 0 deletions
diff --git a/cpu/ozone/lw_back_end_impl.hh b/cpu/ozone/lw_back_end_impl.hh new file mode 100644 index 000000000..41b4ea24b --- /dev/null +++ b/cpu/ozone/lw_back_end_impl.hh @@ -0,0 +1,1693 @@ +/* + * Copyright (c) 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 "cpu/checker/cpu.hh" +#include "cpu/ozone/lw_back_end.hh" +#include "encumbered/cpu/full/op_class.hh" + +template <class Impl> +void +LWBackEnd<Impl>::generateTrapEvent(Tick latency) +{ + DPRINTF(BE, "Generating trap event\n"); + + TrapEvent *trap = new TrapEvent(this); + + trap->schedule(curTick + cpu->cycles(latency)); + + thread->trapPending = true; +} + +template <class Impl> +int +LWBackEnd<Impl>::wakeDependents(DynInstPtr &inst, bool memory_deps) +{ + assert(!inst->isSquashed()); + std::vector<DynInstPtr> &dependents = memory_deps ? inst->getMemDeps() : + inst->getDependents(); + int num_outputs = dependents.size(); + + DPRINTF(BE, "Waking instruction [sn:%lli] dependents in IQ\n", inst->seqNum); + + for (int i = 0; i < num_outputs; i++) { + DynInstPtr dep_inst = dependents[i]; + if (!memory_deps) { + dep_inst->markSrcRegReady(); + } else { + if (!dep_inst->isSquashed()) + dep_inst->markMemInstReady(inst.get()); + } + + DPRINTF(BE, "Marking source reg ready [sn:%lli] in IQ\n", dep_inst->seqNum); + + if (dep_inst->readyToIssue() && dep_inst->isInROB() && + !dep_inst->isNonSpeculative() && !dep_inst->isStoreConditional() && + dep_inst->memDepReady() && !dep_inst->isMemBarrier() && + !dep_inst->isWriteBarrier()) { + DPRINTF(BE, "Adding instruction to exeList [sn:%lli]\n", + dep_inst->seqNum); + exeList.push(dep_inst); + if (dep_inst->iqItValid) { + DPRINTF(BE, "Removing instruction from waiting list\n"); + waitingList.erase(dep_inst->iqIt); + waitingInsts--; + dep_inst->iqItValid = false; + assert(waitingInsts >= 0); + } + if (dep_inst->isMemRef()) { + removeWaitingMemOp(dep_inst); + DPRINTF(BE, "Issued a waiting mem op [sn:%lli]\n", + dep_inst->seqNum); + } + } + } + return num_outputs; +} + +template <class Impl> +void +LWBackEnd<Impl>::rescheduleMemInst(DynInstPtr &inst) +{ + replayList.push_front(inst); +} + +template <class Impl> +LWBackEnd<Impl>::TrapEvent::TrapEvent(LWBackEnd<Impl> *_be) + : Event(&mainEventQueue, CPU_Tick_Pri), be(_be) +{ + this->setFlags(Event::AutoDelete); +} + +template <class Impl> +void +LWBackEnd<Impl>::TrapEvent::process() +{ + be->trapSquash = true; +} + +template <class Impl> +const char * +LWBackEnd<Impl>::TrapEvent::description() +{ + return "Trap event"; +} + +template <class Impl> +void +LWBackEnd<Impl>::replayMemInst(DynInstPtr &inst) +{ + bool found_inst = false; + while (!replayList.empty()) { + exeList.push(replayList.front()); + if (replayList.front() == inst) { + found_inst = true; + } + replayList.pop_front(); + } + assert(found_inst); +} + +template<class Impl> +LWBackEnd<Impl>::LdWritebackEvent::LdWritebackEvent(DynInstPtr &_inst, + LWBackEnd<Impl> *_be) + : Event(&mainEventQueue), inst(_inst), be(_be), dcacheMiss(false) +{ + this->setFlags(Event::AutoDelete); +} + +template<class Impl> +void +LWBackEnd<Impl>::LdWritebackEvent::process() +{ + DPRINTF(BE, "Load writeback event [sn:%lli]\n", inst->seqNum); +// DPRINTF(Activity, "Activity: Ld Writeback event [sn:%lli]\n", inst->seqNum); + + //iewStage->ldstQueue.removeMSHR(inst->threadNumber,inst->seqNum); + +// iewStage->wakeCPU(); + + if (be->isSwitchedOut()) + return; + + if (dcacheMiss) { + be->removeDcacheMiss(inst); + } + + if (inst->isSquashed()) { + inst = NULL; + return; + } + + if (!inst->isExecuted()) { + inst->setExecuted(); + + // Execute again to copy data to proper place. + inst->completeAcc(); + } + + // Need to insert instruction into queue to commit + be->instToCommit(inst); + + //wroteToTimeBuffer = true; +// iewStage->activityThisCycle(); + + inst = NULL; +} + +template<class Impl> +const char * +LWBackEnd<Impl>::LdWritebackEvent::description() +{ + return "Load writeback event"; +} + + +template <class Impl> +LWBackEnd<Impl>::DCacheCompletionEvent::DCacheCompletionEvent(LWBackEnd *_be) + : Event(&mainEventQueue, CPU_Tick_Pri), be(_be) +{ +} + +template <class Impl> +void +LWBackEnd<Impl>::DCacheCompletionEvent::process() +{ +} + +template <class Impl> +const char * +LWBackEnd<Impl>::DCacheCompletionEvent::description() +{ + return "Cache completion event"; +} + +template <class Impl> +LWBackEnd<Impl>::LWBackEnd(Params *params) + : d2i(5, 5), i2e(5, 5), e2c(5, 5), numInstsToWB(5, 5), + trapSquash(false), xcSquash(false), cacheCompletionEvent(this), + dcacheInterface(params->dcacheInterface), width(params->backEndWidth), + exactFullStall(true) +{ + numROBEntries = params->numROBEntries; + numInsts = 0; + numDispatchEntries = 32; + maxOutstandingMemOps = params->maxOutstandingMemOps; + numWaitingMemOps = 0; + waitingInsts = 0; + switchedOut = false; + switchPending = false; + + LSQ.setBE(this); + + // Setup IQ and LSQ with their parameters here. + instsToDispatch = d2i.getWire(-1); + + instsToExecute = i2e.getWire(-1); + + dispatchWidth = params->dispatchWidth ? params->dispatchWidth : width; + issueWidth = params->issueWidth ? params->issueWidth : width; + wbWidth = params->wbWidth ? params->wbWidth : width; + commitWidth = params->commitWidth ? params->commitWidth : width; + + LSQ.init(params, params->LQEntries, params->SQEntries, 0); + + dispatchStatus = Running; +} + +template <class Impl> +std::string +LWBackEnd<Impl>::name() const +{ + return cpu->name() + ".backend"; +} + +template <class Impl> +void +LWBackEnd<Impl>::regStats() +{ + using namespace Stats; + rob_cap_events + .init(cpu->number_of_threads) + .name(name() + ".ROB:cap_events") + .desc("number of cycles where ROB cap was active") + .flags(total) + ; + + rob_cap_inst_count + .init(cpu->number_of_threads) + .name(name() + ".ROB:cap_inst") + .desc("number of instructions held up by ROB cap") + .flags(total) + ; + + iq_cap_events + .init(cpu->number_of_threads) + .name(name() +".IQ:cap_events" ) + .desc("number of cycles where IQ cap was active") + .flags(total) + ; + + iq_cap_inst_count + .init(cpu->number_of_threads) + .name(name() + ".IQ:cap_inst") + .desc("number of instructions held up by IQ cap") + .flags(total) + ; + + + exe_inst + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:count") + .desc("number of insts issued") + .flags(total) + ; + + exe_swp + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:swp") + .desc("number of swp insts issued") + .flags(total) + ; + + exe_nop + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:nop") + .desc("number of nop insts issued") + .flags(total) + ; + + exe_refs + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:refs") + .desc("number of memory reference insts issued") + .flags(total) + ; + + exe_loads + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:loads") + .desc("number of load insts issued") + .flags(total) + ; + + exe_branches + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:branches") + .desc("Number of branches issued") + .flags(total) + ; + + issued_ops + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:op_count") + .desc("number of insts issued") + .flags(total) + ; + +/* + for (int i=0; i<Num_OpClasses; ++i) { + stringstream subname; + subname << opClassStrings[i] << "_delay"; + issue_delay_dist.subname(i, subname.str()); + } +*/ + // + // Other stats + // + lsq_forw_loads + .init(cpu->number_of_threads) + .name(name() + ".LSQ:forw_loads") + .desc("number of loads forwarded via LSQ") + .flags(total) + ; + + inv_addr_loads + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:addr_loads") + .desc("number of invalid-address loads") + .flags(total) + ; + + inv_addr_swpfs + .init(cpu->number_of_threads) + .name(name() + ".ISSUE:addr_swpfs") + .desc("number of invalid-address SW prefetches") + .flags(total) + ; + + lsq_blocked_loads + .init(cpu->number_of_threads) + .name(name() + ".LSQ:blocked_loads") + .desc("number of ready loads not issued due to memory disambiguation") + .flags(total) + ; + + lsqInversion + .name(name() + ".ISSUE:lsq_invert") + .desc("Number of times LSQ instruction issued early") + ; + + n_issued_dist + .init(issueWidth + 1) + .name(name() + ".ISSUE:issued_per_cycle") + .desc("Number of insts issued each cycle") + .flags(total | pdf | dist) + ; + issue_delay_dist + .init(Num_OpClasses,0,99,2) + .name(name() + ".ISSUE:") + .desc("cycles from operands ready to issue") + .flags(pdf | cdf) + ; + + queue_res_dist + .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) { + queue_res_dist.subname(i, opClassStrings[i]); + } + + writeback_count + .init(cpu->number_of_threads) + .name(name() + ".WB:count") + .desc("cumulative count of insts written-back") + .flags(total) + ; + + producer_inst + .init(cpu->number_of_threads) + .name(name() + ".WB:producers") + .desc("num instructions producing a value") + .flags(total) + ; + + consumer_inst + .init(cpu->number_of_threads) + .name(name() + ".WB:consumers") + .desc("num instructions consuming a value") + .flags(total) + ; + + wb_penalized + .init(cpu->number_of_threads) + .name(name() + ".WB:penalized") + .desc("number of instrctions required to write to 'other' IQ") + .flags(total) + ; + + + wb_penalized_rate + .name(name() + ".WB:penalized_rate") + .desc ("fraction of instructions written-back that wrote to 'other' IQ") + .flags(total) + ; + + wb_penalized_rate = wb_penalized / writeback_count; + + wb_fanout + .name(name() + ".WB:fanout") + .desc("average fanout of values written-back") + .flags(total) + ; + + wb_fanout = producer_inst / consumer_inst; + + wb_rate + .name(name() + ".WB:rate") + .desc("insts written-back per cycle") + .flags(total) + ; + wb_rate = writeback_count / cpu->numCycles; + + stat_com_inst + .init(cpu->number_of_threads) + .name(name() + ".COM:count") + .desc("Number of instructions committed") + .flags(total) + ; + + stat_com_swp + .init(cpu->number_of_threads) + .name(name() + ".COM:swp_count") + .desc("Number of s/w prefetches committed") + .flags(total) + ; + + stat_com_refs + .init(cpu->number_of_threads) + .name(name() + ".COM:refs") + .desc("Number of memory references committed") + .flags(total) + ; + + stat_com_loads + .init(cpu->number_of_threads) + .name(name() + ".COM:loads") + .desc("Number of loads committed") + .flags(total) + ; + + stat_com_membars + .init(cpu->number_of_threads) + .name(name() + ".COM:membars") + .desc("Number of memory barriers committed") + .flags(total) + ; + + stat_com_branches + .init(cpu->number_of_threads) + .name(name() + ".COM:branches") + .desc("Number of branches committed") + .flags(total) + ; + n_committed_dist + .init(0,commitWidth,1) + .name(name() + ".COM:committed_per_cycle") + .desc("Number of insts commited each cycle") + .flags(pdf) + ; + + // + // 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 + // + commit_eligible + .init(cpu->number_of_threads) + .name(name() + ".COM:bw_limited") + .desc("number of insts not committed due to BW limits") + .flags(total) + ; + + commit_eligible_samples + .name(name() + ".COM:bw_lim_events") + .desc("number cycles where commit BW limit reached") + ; + + squashedInsts + .init(cpu->number_of_threads) + .name(name() + ".COM:squashed_insts") + .desc("Number of instructions removed from inst list") + ; + + ROBSquashedInsts + .init(cpu->number_of_threads) + .name(name() + ".COM:rob_squashed_insts") + .desc("Number of instructions removed from inst list when they reached the head of the ROB") + ; + + ROB_fcount + .name(name() + ".ROB:full_count") + .desc("number of cycles where ROB was full") + ; + + ROB_count + .init(cpu->number_of_threads) + .name(name() + ".ROB:occupancy") + .desc(name() + ".ROB occupancy (cumulative)") + .flags(total) + ; + + ROB_full_rate + .name(name() + ".ROB:full_rate") + .desc("ROB full per cycle") + ; + ROB_full_rate = ROB_fcount / cpu->numCycles; + + ROB_occ_rate + .name(name() + ".ROB:occ_rate") + .desc("ROB occupancy rate") + .flags(total) + ; + ROB_occ_rate = ROB_count / cpu->numCycles; + + ROB_occ_dist + .init(cpu->number_of_threads,0,numROBEntries,2) + .name(name() + ".ROB:occ_dist") + .desc("ROB Occupancy per cycle") + .flags(total | cdf) + ; +} + +template <class Impl> +void +LWBackEnd<Impl>::setCPU(FullCPU *cpu_ptr) +{ + cpu = cpu_ptr; + LSQ.setCPU(cpu_ptr); + checker = cpu->checker; +} + +template <class Impl> +void +LWBackEnd<Impl>::setCommBuffer(TimeBuffer<CommStruct> *_comm) +{ + comm = _comm; + toIEW = comm->getWire(0); + fromCommit = comm->getWire(-1); +} + +#if FULL_SYSTEM +template <class Impl> +void +LWBackEnd<Impl>::checkInterrupts() +{ + if (cpu->checkInterrupts && + cpu->check_interrupts() && + !cpu->inPalMode(thread->readPC()) && + !trapSquash && + !xcSquash) { + frontEnd->interruptPending = true; + if (robEmpty() && !LSQ.hasStoresToWB()) { + // Will need to squash all instructions currently in flight and have + // the interrupt handler restart at the last non-committed inst. + // Most of that can be handled through the trap() function. The + // processInterrupts() function really just checks for interrupts + // and then calls trap() if there is an interrupt present. + + // Not sure which thread should be the one to interrupt. For now + // always do thread 0. + assert(!thread->inSyscall); + thread->inSyscall = true; + + // CPU will handle implementation of the interrupt. + cpu->processInterrupts(); + + // Now squash or record that I need to squash this cycle. + commitStatus = TrapPending; + + // Exit state update mode to avoid accidental updating. + thread->inSyscall = false; + + // Generate trap squash event. + generateTrapEvent(); + + DPRINTF(BE, "Interrupt detected.\n"); + } else { + DPRINTF(BE, "Interrupt must wait for ROB to drain.\n"); + } + } +} + +template <class Impl> +void +LWBackEnd<Impl>::handleFault(Fault &fault, Tick latency) +{ + DPRINTF(BE, "Handling fault!\n"); + + assert(!thread->inSyscall); + + thread->inSyscall = true; + + // Consider holding onto the trap and waiting until the trap event + // happens for this to be executed. + fault->invoke(thread->getXCProxy()); + + // Exit state update mode to avoid accidental updating. + thread->inSyscall = false; + + commitStatus = TrapPending; + + // Generate trap squash event. + generateTrapEvent(latency); +} +#endif + +template <class Impl> +void +LWBackEnd<Impl>::tick() +{ + DPRINTF(BE, "Ticking back end\n"); + + if (switchPending && robEmpty() && !LSQ.hasStoresToWB()) { + cpu->signalSwitched(); + return; + } + + ROB_count[0]+= numInsts; + + wbCycle = 0; + + // Read in any done instruction information and update the IQ or LSQ. + updateStructures(); + +#if FULL_SYSTEM + checkInterrupts(); + + if (trapSquash) { + assert(!xcSquash); + squashFromTrap(); + } else if (xcSquash) { + squashFromXC(); + } +#endif + + if (dispatchStatus != Blocked) { + dispatchInsts(); + } else { + checkDispatchStatus(); + } + + if (commitStatus != TrapPending) { + executeInsts(); + + commitInsts(); + } + + LSQ.writebackStores(); + + DPRINTF(BE, "Waiting insts: %i, mem ops: %i, ROB entries in use: %i, " + "LSQ loads: %i, LSQ stores: %i\n", + waitingInsts, numWaitingMemOps, numInsts, + LSQ.numLoads(), LSQ.numStores()); + +#ifdef DEBUG + assert(numInsts == instList.size()); + assert(waitingInsts == waitingList.size()); + assert(numWaitingMemOps == waitingMemOps.size()); + assert(!switchedOut); +#endif +} + +template <class Impl> +void +LWBackEnd<Impl>::updateStructures() +{ + if (fromCommit->doneSeqNum) { + LSQ.commitLoads(fromCommit->doneSeqNum); + LSQ.commitStores(fromCommit->doneSeqNum); + } + + if (fromCommit->nonSpecSeqNum) { + if (fromCommit->uncached) { +// LSQ.executeLoad(fromCommit->lqIdx); + } else { +// IQ.scheduleNonSpec( +// fromCommit->nonSpecSeqNum); + } + } +} + +template <class Impl> +void +LWBackEnd<Impl>::addToLSQ(DynInstPtr &inst) +{ + // Do anything LSQ specific here? + LSQ.insert(inst); +} + +template <class Impl> +void +LWBackEnd<Impl>::dispatchInsts() +{ + DPRINTF(BE, "Trying to dispatch instructions.\n"); + + while (numInsts < numROBEntries && + numWaitingMemOps < maxOutstandingMemOps) { + // Get instruction from front of time buffer + DynInstPtr inst = frontEnd->getInst(); + if (!inst) { + break; + } else if (inst->isSquashed()) { + continue; + } + + ++numInsts; + instList.push_front(inst); + + inst->setInROB(); + + DPRINTF(BE, "Dispatching instruction [sn:%lli] PC:%#x\n", + inst->seqNum, inst->readPC()); + + for (int i = 0; i < inst->numDestRegs(); ++i) + renameTable[inst->destRegIdx(i)] = inst; + + if (inst->isMemBarrier() || inst->isWriteBarrier()) { + if (memBarrier) { + DPRINTF(BE, "Instruction [sn:%lli] is waiting on " + "barrier [sn:%lli].\n", + inst->seqNum, memBarrier->seqNum); + memBarrier->addMemDependent(inst); + inst->addSrcMemInst(memBarrier); + } + memBarrier = inst; + inst->setCanCommit(); + } else if (inst->readyToIssue() && + !inst->isNonSpeculative() && + !inst->isStoreConditional()) { + if (inst->isMemRef()) { + + LSQ.insert(inst); + if (memBarrier) { + DPRINTF(BE, "Instruction [sn:%lli] is waiting on " + "barrier [sn:%lli].\n", + inst->seqNum, memBarrier->seqNum); + memBarrier->addMemDependent(inst); + inst->addSrcMemInst(memBarrier); + addWaitingMemOp(inst); + + waitingList.push_front(inst); + inst->iqIt = waitingList.begin(); + inst->iqItValid = true; + waitingInsts++; + } else { + DPRINTF(BE, "Instruction [sn:%lli] ready, addding to " + "exeList.\n", + inst->seqNum); + exeList.push(inst); + } + } else if (inst->isNop()) { + DPRINTF(BE, "Nop encountered [sn:%lli], skipping exeList.\n", + inst->seqNum); + inst->setIssued(); + inst->setExecuted(); + inst->setCanCommit(); + } else { + DPRINTF(BE, "Instruction [sn:%lli] ready, addding to " + "exeList.\n", + inst->seqNum); + exeList.push(inst); + } + } else { + if (inst->isNonSpeculative() || inst->isStoreConditional()) { + inst->setCanCommit(); + DPRINTF(BE, "Adding non speculative instruction\n"); + } + + if (inst->isMemRef()) { + addWaitingMemOp(inst); + LSQ.insert(inst); + if (memBarrier) { + memBarrier->addMemDependent(inst); + inst->addSrcMemInst(memBarrier); + + DPRINTF(BE, "Instruction [sn:%lli] is waiting on " + "barrier [sn:%lli].\n", + inst->seqNum, memBarrier->seqNum); + } + } + + DPRINTF(BE, "Instruction [sn:%lli] not ready, addding to " + "waitingList.\n", + inst->seqNum); + waitingList.push_front(inst); + inst->iqIt = waitingList.begin(); + inst->iqItValid = true; + waitingInsts++; + } + } + + // Check if IQ or LSQ is full. If so we'll need to break and stop + // removing instructions. Also update the number of insts to remove + // from the queue. Check here if we don't care about exact stall + // conditions. +/* + bool stall = false; + if (IQ.isFull()) { + DPRINTF(BE, "IQ is full!\n"); + stall = true; + } else if (LSQ.isFull()) { + DPRINTF(BE, "LSQ is full!\n"); + stall = true; + } else if (isFull()) { + DPRINTF(BE, "ROB is full!\n"); + stall = true; + ROB_fcount++; + } + if (stall) { + d2i.advance(); + dispatchStall(); + return; + } +*/ +} + +template <class Impl> +void +LWBackEnd<Impl>::dispatchStall() +{ + dispatchStatus = Blocked; + if (!cpu->decoupledFrontEnd) { + // Tell front end to stall here through a timebuffer, or just tell + // it directly. + } +} + +template <class Impl> +void +LWBackEnd<Impl>::checkDispatchStatus() +{ + DPRINTF(BE, "Checking dispatch status\n"); + assert(dispatchStatus == Blocked); + if (!LSQ.isFull() && !isFull()) { + DPRINTF(BE, "Dispatch no longer blocked\n"); + dispatchStatus = Running; + dispatchInsts(); + } +} + +template <class Impl> +void +LWBackEnd<Impl>::executeInsts() +{ + DPRINTF(BE, "Trying to execute instructions\n"); + + int num_executed = 0; + while (!exeList.empty() && num_executed < issueWidth) { + DynInstPtr inst = exeList.top(); + + DPRINTF(BE, "Executing inst [sn:%lli] PC: %#x\n", + inst->seqNum, inst->readPC()); + + // Check if the instruction is squashed; if so then skip it + // and don't count it towards the FU usage. + if (inst->isSquashed()) { + DPRINTF(BE, "Execute: Instruction was squashed.\n"); + + // Not sure how to handle this plus the method of sending # of + // instructions to use. Probably will just have to count it + // towards the bandwidth usage, but not the FU usage. + ++num_executed; + + // Consider this instruction executed so that commit can go + // ahead and retire the instruction. + inst->setExecuted(); + + // Not sure if I should set this here or just let commit try to + // commit any squashed instructions. I like the latter a bit more. + inst->setCanCommit(); + +// ++iewExecSquashedInsts; + exeList.pop(); + + continue; + } + + Fault fault = NoFault; + + // Execute instruction. + // Note that if the instruction faults, it will be handled + // at the commit stage. + if (inst->isMemRef() && + (!inst->isDataPrefetch() && !inst->isInstPrefetch())) { + if (dcacheInterface->isBlocked()) { + // Should I move the instruction aside? + DPRINTF(BE, "Execute: dcache is blocked\n"); + break; + } + DPRINTF(BE, "Execute: Initiating access for memory " + "reference.\n"); + + if (inst->isLoad()) { + LSQ.executeLoad(inst); + } else if (inst->isStore()) { + LSQ.executeStore(inst); + if (inst->req && !(inst->req->flags & LOCKED)) { + inst->setExecuted(); + + instToCommit(inst); + } + } else { + panic("Unknown mem type!"); + } + } else { + inst->execute(); + + inst->setExecuted(); + + instToCommit(inst); + } + + updateExeInstStats(inst); + + ++funcExeInst; + ++num_executed; + + exeList.pop(); + + if (inst->mispredicted()) { + squashDueToBranch(inst); + break; + } else if (LSQ.violation()) { + // Get the DynInst that caused the violation. Note that this + // clears the violation signal. + DynInstPtr violator; + violator = LSQ.getMemDepViolator(); + + DPRINTF(BE, "LDSTQ detected a violation. Violator PC: " + "%#x, inst PC: %#x. Addr is: %#x.\n", + violator->readPC(), inst->readPC(), inst->physEffAddr); + + // Squash. + squashDueToMemViolation(inst); + } + } + + issued_ops[0]+= num_executed; + n_issued_dist[num_executed]++; +} + +template<class Impl> +void +LWBackEnd<Impl>::instToCommit(DynInstPtr &inst) +{ + + DPRINTF(BE, "Sending instructions to commit [sn:%lli] PC %#x.\n", + inst->seqNum, inst->readPC()); + + if (!inst->isSquashed()) { + DPRINTF(BE, "Writing back instruction [sn:%lli] PC %#x.\n", + inst->seqNum, inst->readPC()); + + inst->setCanCommit(); + + if (inst->isExecuted()) { + inst->setResultReady(); + int dependents = wakeDependents(inst); + if (dependents) { + producer_inst[0]++; + consumer_inst[0]+= dependents; + } + } + } + + writeback_count[0]++; +} +#if 0 +template <class Impl> +void +LWBackEnd<Impl>::writebackInsts() +{ + int wb_width = wbWidth; + // Using this method I'm not quite sure how to prevent an + // instruction from waking its own dependents multiple times, + // without the guarantee that commit always has enough bandwidth + // to accept all instructions being written back. This guarantee + // might not be too unrealistic. + InstListIt wb_inst_it = writeback.begin(); + InstListIt wb_end_it = writeback.end(); + int inst_num = 0; + int consumer_insts = 0; + + for (; inst_num < wb_width && + wb_inst_it != wb_end_it; inst_num++) { + DynInstPtr inst = (*wb_inst_it); + + // Some instructions will be sent to commit without having + // executed because they need commit to handle them. + // E.g. Uncached loads have not actually executed when they + // are first sent to commit. Instead commit must tell the LSQ + // when it's ready to execute the uncached load. + if (!inst->isSquashed()) { + DPRINTF(BE, "Writing back instruction [sn:%lli] PC %#x.\n", + inst->seqNum, inst->readPC()); + + inst->setCanCommit(); + inst->setResultReady(); + + if (inst->isExecuted()) { + int dependents = wakeDependents(inst); + if (dependents) { + producer_inst[0]++; + consumer_insts+= dependents; + } + } + } + + writeback.erase(wb_inst_it++); + } + LSQ.writebackStores(); + consumer_inst[0]+= consumer_insts; + writeback_count[0]+= inst_num; +} +#endif +template <class Impl> +bool +LWBackEnd<Impl>::commitInst(int inst_num) +{ + // Read instruction from the head of the ROB + DynInstPtr inst = instList.back(); + + // Make sure instruction is valid + assert(inst); + + if (!inst->readyToCommit()) + return false; + + DPRINTF(BE, "Trying to commit instruction [sn:%lli] PC:%#x\n", + inst->seqNum, inst->readPC()); + + thread->setPC(inst->readPC()); + thread->setNextPC(inst->readNextPC()); + inst->reachedCommit = true; + + // If the instruction is not executed yet, then it is a non-speculative + // or store inst. Signal backwards that it should be executed. + if (!inst->isExecuted()) { + if (inst->isNonSpeculative() || + inst->isStoreConditional() || + inst->isMemBarrier() || + inst->isWriteBarrier()) { +#if !FULL_SYSTEM + // Hack to make sure syscalls 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 || LSQ.hasStoresToWB()) +#else + if ((inst->isMemBarrier() || inst->isWriteBarrier() || + inst->isQuiesce()) && + LSQ.hasStoresToWB()) +#endif + { + DPRINTF(BE, "Waiting for all stores to writeback.\n"); + return false; + } + + DPRINTF(BE, "Encountered a store or non-speculative " + "instruction at the head of the ROB, PC %#x.\n", + inst->readPC()); + + if (inst->isMemBarrier() || inst->isWriteBarrier()) { + DPRINTF(BE, "Waking dependents on barrier [sn:%lli]\n", + inst->seqNum); + assert(memBarrier); + wakeDependents(inst, true); + if (memBarrier == inst) + memBarrier = NULL; + inst->clearMemDependents(); + } + + // Send back the non-speculative instruction's sequence number. + if (inst->iqItValid) { + DPRINTF(BE, "Removing instruction from waiting list\n"); + waitingList.erase(inst->iqIt); + inst->iqItValid = false; + waitingInsts--; + assert(waitingInsts >= 0); + if (inst->isStore()) + removeWaitingMemOp(inst); + } + + exeList.push(inst); + + // Change the instruction so it won't try to commit again until + // it is executed. + inst->clearCanCommit(); + +// ++commitNonSpecStalls; + + return false; + } else if (inst->isLoad()) { + DPRINTF(BE, "[sn:%lli]: Uncached load, PC %#x.\n", + inst->seqNum, inst->readPC()); + + // Send back the non-speculative instruction's sequence + // number. Maybe just tell the lsq to re-execute the load. + + // Send back the non-speculative instruction's sequence number. + if (inst->iqItValid) { + DPRINTF(BE, "Removing instruction from waiting list\n"); + waitingList.erase(inst->iqIt); + inst->iqItValid = false; + waitingInsts--; + assert(waitingInsts >= 0); + removeWaitingMemOp(inst); + } + replayMemInst(inst); + + inst->clearCanCommit(); + + return false; + } else { + panic("Trying to commit un-executed instruction " + "of unknown type!\n"); + } + } + + // Not handled for now. + assert(!inst->isThreadSync()); + assert(inst->memDepReady()); + // Stores will mark themselves as totally completed as they need + // to wait to writeback to memory. @todo: Hack...attempt to fix + // having the checker be forced to wait until a store completes in + // order to check all of the instructions. If the store at the + // head of the check list misses, but a later store hits, then + // loads in the checker may see the younger store values instead + // of the store they should see. Either the checker needs its own + // memory (annoying to update), its own store buffer (how to tell + // which value is correct?), or something else... + if (!inst->isStore()) { + inst->setCompleted(); + } + // Check if the instruction caused a fault. If so, trap. + Fault inst_fault = inst->getFault(); + + // Use checker prior to updating anything due to traps or PC + // based events. + if (checker) { + checker->tick(inst); + } + + if (inst_fault != NoFault) { + DPRINTF(BE, "Inst [sn:%lli] PC %#x has a fault\n", + inst->seqNum, inst->readPC()); + + // Instruction is completed as it has a fault. + inst->setCompleted(); + + if (LSQ.hasStoresToWB()) { + DPRINTF(BE, "Stores still in flight, will wait until drained.\n"); + return false; + } else if (inst_num != 0) { + DPRINTF(BE, "Will wait until instruction is head of commit group.\n"); + return false; + } else if (checker && inst->isStore()) { + checker->tick(inst); + } + + thread->setInst( + static_cast<TheISA::MachInst>(inst->staticInst->machInst)); +#if FULL_SYSTEM + handleFault(inst_fault); + return false; +#else // !FULL_SYSTEM + panic("fault (%d) detected @ PC %08p", inst_fault, + inst->PC); +#endif // FULL_SYSTEM + } + + int freed_regs = 0; + + for (int i = 0; i < inst->numDestRegs(); ++i) { + DPRINTF(BE, "Commit rename map setting reg %i to [sn:%lli]\n", + (int)inst->destRegIdx(i), inst->seqNum); + thread->renameTable[inst->destRegIdx(i)] = inst; + ++freed_regs; + } + + if (inst->traceData) { + inst->traceData->setFetchSeq(inst->seqNum); + inst->traceData->setCPSeq(thread->numInst); + inst->traceData->finalize(); + inst->traceData = NULL; + } + + inst->clearDependents(); + + frontEnd->addFreeRegs(freed_regs); + + instList.pop_back(); + + --numInsts; + ++thread->funcExeInst; + // Maybe move this to where the fault is handled; if the fault is + // handled, don't try to set this myself as the fault will set it. + // If not, then I set thread->PC = thread->nextPC and + // thread->nextPC = thread->nextPC + 4. + thread->setPC(thread->readNextPC()); + thread->setNextPC(thread->readNextPC() + sizeof(TheISA::MachInst)); + updateComInstStats(inst); + + // Write the done sequence number here. + toIEW->doneSeqNum = inst->seqNum; + lastCommitCycle = curTick; + +#if FULL_SYSTEM + int count = 0; + Addr oldpc; + do { + if (count == 0) + assert(!thread->inSyscall && !thread->trapPending); + oldpc = thread->readPC(); + cpu->system->pcEventQueue.service( + thread->getXCProxy()); + count++; + } while (oldpc != thread->readPC()); + if (count > 1) { + DPRINTF(BE, "PC skip function event, stopping commit\n"); + xcSquash = true; + return false; + } +#endif + return true; +} + +template <class Impl> +void +LWBackEnd<Impl>::commitInsts() +{ + // Not sure this should be a loop or not. + int inst_num = 0; + while (!instList.empty() && inst_num < commitWidth) { + if (instList.back()->isSquashed()) { + instList.back()->clearDependents(); + instList.pop_back(); + --numInsts; + ROBSquashedInsts[instList.back()->threadNumber]++; + continue; + } + + if (!commitInst(inst_num++)) { + DPRINTF(BE, "Can't commit, Instruction [sn:%lli] PC " + "%#x is head of ROB and not ready\n", + instList.back()->seqNum, instList.back()->readPC()); + --inst_num; + break; + } + } + n_committed_dist.sample(inst_num); +} + +template <class Impl> +void +LWBackEnd<Impl>::squash(const InstSeqNum &sn) +{ + LSQ.squash(sn); + + int freed_regs = 0; + InstListIt waiting_list_end = waitingList.end(); + InstListIt insts_it = waitingList.begin(); + + while (insts_it != waiting_list_end && (*insts_it)->seqNum > sn) + { + if ((*insts_it)->isSquashed()) { + ++insts_it; + continue; + } + DPRINTF(BE, "Squashing instruction on waitingList PC %#x, [sn:%lli].\n", + (*insts_it)->readPC(), + (*insts_it)->seqNum); + + if ((*insts_it)->isMemRef()) { + DPRINTF(BE, "Squashing a waiting mem op [sn:%lli]\n", + (*insts_it)->seqNum); + removeWaitingMemOp((*insts_it)); + } + + waitingList.erase(insts_it++); + waitingInsts--; + } + assert(waitingInsts >= 0); + + insts_it = instList.begin(); + + while (!instList.empty() && (*insts_it)->seqNum > sn) + { + if ((*insts_it)->isSquashed()) { + ++insts_it; + continue; + } + DPRINTF(BE, "Squashing instruction on inst list PC %#x, [sn:%lli].\n", + (*insts_it)->readPC(), + (*insts_it)->seqNum); + + // Mark the instruction as squashed, and ready to commit so that + // it can drain out of the pipeline. + (*insts_it)->setSquashed(); + + (*insts_it)->setCanCommit(); + + (*insts_it)->removeInROB(); + + for (int i = 0; i < (*insts_it)->numDestRegs(); ++i) { + DynInstPtr prev_dest = (*insts_it)->getPrevDestInst(i); + DPRINTF(BE, "Commit rename map setting reg %i to [sn:%lli]\n", + (int)(*insts_it)->destRegIdx(i), prev_dest->seqNum); + renameTable[(*insts_it)->destRegIdx(i)] = prev_dest; + ++freed_regs; + } + + (*insts_it)->clearDependents(); + + squashedInsts[(*insts_it)->threadNumber]++; + + instList.erase(insts_it++); + --numInsts; + } + + insts_it = waitingList.begin(); + while (!waitingList.empty() && insts_it != waitingList.end()) { + if ((*insts_it)->seqNum < sn) { + ++insts_it; + continue; + } + assert((*insts_it)->isSquashed()); + + waitingList.erase(insts_it++); + waitingInsts--; + } + + while (memBarrier && memBarrier->seqNum > sn) { + DPRINTF(BE, "[sn:%lli] Memory barrier squashed (or previously " + "squashed)\n", memBarrier->seqNum); + memBarrier->clearMemDependents(); + if (memBarrier->memDepReady()) { + DPRINTF(BE, "No previous barrier\n"); + memBarrier = NULL; + } else { + std::list<DynInstPtr> &srcs = memBarrier->getMemSrcs(); + memBarrier = srcs.front(); + srcs.pop_front(); + assert(srcs.empty()); + DPRINTF(BE, "Previous barrier: [sn:%lli]\n", + memBarrier->seqNum); + } + } + + frontEnd->addFreeRegs(freed_regs); +} + +template <class Impl> +void +LWBackEnd<Impl>::squashFromXC() +{ + InstSeqNum squashed_inst = robEmpty() ? 0 : instList.back()->seqNum - 1; + squash(squashed_inst); + frontEnd->squash(squashed_inst, thread->readPC(), + false, false); + frontEnd->interruptPending = false; + + thread->trapPending = false; + thread->inSyscall = false; + xcSquash = false; + commitStatus = Running; +} + +template <class Impl> +void +LWBackEnd<Impl>::squashFromTrap() +{ + InstSeqNum squashed_inst = robEmpty() ? 0 : instList.back()->seqNum - 1; + squash(squashed_inst); + frontEnd->squash(squashed_inst, thread->readPC(), + false, false); + frontEnd->interruptPending = false; + + thread->trapPending = false; + thread->inSyscall = false; + trapSquash = false; + commitStatus = Running; +} + +template <class Impl> +void +LWBackEnd<Impl>::squashDueToBranch(DynInstPtr &inst) +{ + // Update the branch predictor state I guess + DPRINTF(BE, "Squashing due to branch [sn:%lli], will restart at PC %#x\n", + inst->seqNum, inst->readNextPC()); + squash(inst->seqNum); + frontEnd->squash(inst->seqNum, inst->readNextPC(), + true, inst->mispredicted()); +} + +template <class Impl> +void +LWBackEnd<Impl>::squashDueToMemViolation(DynInstPtr &inst) +{ + // Update the branch predictor state I guess + DPRINTF(BE, "Squashing due to violation [sn:%lli], will restart at PC %#x\n", + inst->seqNum, inst->readNextPC()); + squash(inst->seqNum); + frontEnd->squash(inst->seqNum, inst->readNextPC(), + false, inst->mispredicted()); +} + +template <class Impl> +void +LWBackEnd<Impl>::squashDueToMemBlocked(DynInstPtr &inst) +{ + DPRINTF(IEW, "Memory blocked, squashing load and younger insts, " + "PC: %#x [sn:%i].\n", inst->readPC(), inst->seqNum); + + squash(inst->seqNum - 1); + frontEnd->squash(inst->seqNum - 1, inst->readPC()); +} + +template <class Impl> +void +LWBackEnd<Impl>::fetchFault(Fault &fault) +{ + faultFromFetch = fault; + fetchHasFault = true; +} + +template <class Impl> +void +LWBackEnd<Impl>::switchOut() +{ + switchPending = true; +} + +template <class Impl> +void +LWBackEnd<Impl>::doSwitchOut() +{ + switchedOut = true; + switchPending = false; + // Need to get rid of all committed, non-speculative state and write it + // to memory/XC. In this case this is stores that have committed and not + // yet written back. + assert(robEmpty()); + assert(!LSQ.hasStoresToWB()); + + LSQ.switchOut(); + + squash(0); +} + +template <class Impl> +void +LWBackEnd<Impl>::takeOverFrom(ExecContext *old_xc) +{ + switchedOut = false; + xcSquash = false; + trapSquash = false; + + numInsts = 0; + numWaitingMemOps = 0; + waitingMemOps.clear(); + waitingInsts = 0; + switchedOut = false; + dispatchStatus = Running; + commitStatus = Running; + LSQ.takeOverFrom(old_xc); +} + +template <class Impl> +void +LWBackEnd<Impl>::updateExeInstStats(DynInstPtr &inst) +{ + int thread_number = inst->threadNumber; + + // + // Pick off the software prefetches + // +#ifdef TARGET_ALPHA + if (inst->isDataPrefetch()) + exe_swp[thread_number]++; + else + exe_inst[thread_number]++; +#else + exe_inst[thread_number]++; +#endif + + // + // Control operations + // + if (inst->isControl()) + exe_branches[thread_number]++; + + // + // Memory operations + // + if (inst->isMemRef()) { + exe_refs[thread_number]++; + + if (inst->isLoad()) + exe_loads[thread_number]++; + } +} + +template <class Impl> +void +LWBackEnd<Impl>::updateComInstStats(DynInstPtr &inst) +{ + unsigned tid = inst->threadNumber; + + // keep an instruction count + thread->numInst++; + thread->numInsts++; + + cpu->numInst++; + // + // Pick off the software prefetches + // +#ifdef TARGET_ALPHA + if (inst->isDataPrefetch()) { + stat_com_swp[tid]++; + } else { + stat_com_inst[tid]++; + } +#else + stat_com_inst[tid]++; +#endif + + // + // Control Instructions + // + if (inst->isControl()) + stat_com_branches[tid]++; + + // + // Memory references + // + if (inst->isMemRef()) { + stat_com_refs[tid]++; + + if (inst->isLoad()) { + stat_com_loads[tid]++; + } + } + + if (inst->isMemBarrier()) { + stat_com_membars[tid]++; + } +} + +template <class Impl> +void +LWBackEnd<Impl>::dumpInsts() +{ + int num = 0; + int valid_num = 0; + + InstListIt inst_list_it = --(instList.end()); + + cprintf("ExeList size: %i\n", exeList.size()); + + cprintf("Inst list size: %i\n", instList.size()); + + while (inst_list_it != instList.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()); + + if ((*inst_list_it)->isMemRef()) { + cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone); + } + + cprintf("\n"); + + inst_list_it--; + ++num; + } + + cprintf("Waiting list size: %i\n", waitingList.size()); + + inst_list_it = --(waitingList.end()); + + while (inst_list_it != waitingList.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()); + + if ((*inst_list_it)->isMemRef()) { + cprintf("MemOpDone:%i\n", (*inst_list_it)->memOpDone); + } + + cprintf("\n"); + + inst_list_it--; + ++num; + } + + cprintf("waitingMemOps list size: %i\n", waitingMemOps.size()); + + MemIt waiting_it = waitingMemOps.begin(); + + while (waiting_it != waitingMemOps.end()) + { + cprintf("[sn:%lli] ", (*waiting_it)); + waiting_it++; + ++num; + } + cprintf("\n"); +} |