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Diffstat (limited to 'src/mem/cache/coherence/coherence_protocol.cc')
| -rw-r--r-- | src/mem/cache/coherence/coherence_protocol.cc | 567 |
1 files changed, 567 insertions, 0 deletions
diff --git a/src/mem/cache/coherence/coherence_protocol.cc b/src/mem/cache/coherence/coherence_protocol.cc new file mode 100644 index 000000000..bcf3ce9c5 --- /dev/null +++ b/src/mem/cache/coherence/coherence_protocol.cc @@ -0,0 +1,567 @@ +/* + * Copyright (c) 2002-2005 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: Erik Hallnor + * Steve Reinhardt + * Ron Dreslinski + */ + +/** + * @file + * Definitions of CoherenceProtocol. + */ + +#include <string> + +#include "base/misc.hh" +#include "mem/cache/miss/mshr.hh" +#include "mem/cache/cache.hh" +#include "mem/cache/coherence/coherence_protocol.hh" +#include "sim/builder.hh" + +using namespace std; + + +CoherenceProtocol::StateTransition::StateTransition() + : busCmd(Packet::InvalidCmd), newState(-1), snoopFunc(invalidTransition) +{ +} + + +void +CoherenceProtocol::regStats() +{ + // Even though we count all the possible transitions in the + // requestCount and snoopCount arrays, most of these are invalid, + // so we just select the interesting ones to print here. + + requestCount[Invalid][Packet::ReadReq] + .name(name() + ".read_invalid") + .desc("read misses to invalid blocks") + ; + + requestCount[Invalid][Packet::WriteReq] + .name(name() +".write_invalid") + .desc("write misses to invalid blocks") + ; + + requestCount[Invalid][Packet::SoftPFReq] + .name(name() +".swpf_invalid") + .desc("soft prefetch misses to invalid blocks") + ; + + requestCount[Invalid][Packet::HardPFReq] + .name(name() +".hwpf_invalid") + .desc("hard prefetch misses to invalid blocks") + ; + + requestCount[Shared][Packet::WriteReq] + .name(name() + ".write_shared") + .desc("write misses to shared blocks") + ; + + requestCount[Owned][Packet::WriteReq] + .name(name() + ".write_owned") + .desc("write misses to owned blocks") + ; + + snoopCount[Shared][Packet::ReadReq] + .name(name() + ".snoop_read_shared") + .desc("read snoops on shared blocks") + ; + + snoopCount[Shared][Packet::ReadExReq] + .name(name() + ".snoop_readex_shared") + .desc("readEx snoops on shared blocks") + ; + + snoopCount[Shared][Packet::UpgradeReq] + .name(name() + ".snoop_upgrade_shared") + .desc("upgradee snoops on shared blocks") + ; + + snoopCount[Modified][Packet::ReadReq] + .name(name() + ".snoop_read_modified") + .desc("read snoops on modified blocks") + ; + + snoopCount[Modified][Packet::ReadExReq] + .name(name() + ".snoop_readex_modified") + .desc("readEx snoops on modified blocks") + ; + + snoopCount[Owned][Packet::ReadReq] + .name(name() + ".snoop_read_owned") + .desc("read snoops on owned blocks") + ; + + snoopCount[Owned][Packet::ReadExReq] + .name(name() + ".snoop_readex_owned") + .desc("readEx snoops on owned blocks") + ; + + snoopCount[Owned][Packet::UpgradeReq] + .name(name() + ".snoop_upgrade_owned") + .desc("upgrade snoops on owned blocks") + ; + + snoopCount[Exclusive][Packet::ReadReq] + .name(name() + ".snoop_read_exclusive") + .desc("read snoops on exclusive blocks") + ; + + snoopCount[Exclusive][Packet::ReadExReq] + .name(name() + ".snoop_readex_exclusive") + .desc("readEx snoops on exclusive blocks") + ; + + snoopCount[Shared][Packet::InvalidateReq] + .name(name() + ".snoop_inv_shared") + .desc("Invalidate snoops on shared blocks") + ; + + snoopCount[Owned][Packet::InvalidateReq] + .name(name() + ".snoop_inv_owned") + .desc("Invalidate snoops on owned blocks") + ; + + snoopCount[Exclusive][Packet::InvalidateReq] + .name(name() + ".snoop_inv_exclusive") + .desc("Invalidate snoops on exclusive blocks") + ; + + snoopCount[Modified][Packet::InvalidateReq] + .name(name() + ".snoop_inv_modified") + .desc("Invalidate snoops on modified blocks") + ; + + snoopCount[Invalid][Packet::InvalidateReq] + .name(name() + ".snoop_inv_invalid") + .desc("Invalidate snoops on invalid blocks") + ; + + snoopCount[Shared][Packet::WriteInvalidateReq] + .name(name() + ".snoop_writeinv_shared") + .desc("WriteInvalidate snoops on shared blocks") + ; + + snoopCount[Owned][Packet::WriteInvalidateReq] + .name(name() + ".snoop_writeinv_owned") + .desc("WriteInvalidate snoops on owned blocks") + ; + + snoopCount[Exclusive][Packet::WriteInvalidateReq] + .name(name() + ".snoop_writeinv_exclusive") + .desc("WriteInvalidate snoops on exclusive blocks") + ; + + snoopCount[Modified][Packet::WriteInvalidateReq] + .name(name() + ".snoop_writeinv_modified") + .desc("WriteInvalidate snoops on modified blocks") + ; + + snoopCount[Invalid][Packet::WriteInvalidateReq] + .name(name() + ".snoop_writeinv_invalid") + .desc("WriteInvalidate snoops on invalid blocks") + ; +} + + +bool +CoherenceProtocol::invalidateTrans(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, MSHR *mshr, + CacheBlk::State & new_state) +{ + // invalidate the block + new_state = (blk->status & ~stateMask) | Invalid; + return false; +} + + +bool +CoherenceProtocol::supplyTrans(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state + ) +{ + return true; +} + + +bool +CoherenceProtocol::supplyAndGotoSharedTrans(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state) +{ + new_state = (blk->status & ~stateMask) | Shared; + pkt->flags |= SHARED_LINE; + return supplyTrans(cache, pkt, blk, mshr, new_state); +} + + +bool +CoherenceProtocol::supplyAndGotoOwnedTrans(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state) +{ + new_state = (blk->status & ~stateMask) | Owned; + pkt->flags |= SHARED_LINE; + return supplyTrans(cache, pkt, blk, mshr, new_state); +} + + +bool +CoherenceProtocol::supplyAndInvalidateTrans(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state) +{ + new_state = (blk->status & ~stateMask) | Invalid; + return supplyTrans(cache, pkt, blk, mshr, new_state); +} + +bool +CoherenceProtocol::assertShared(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state) +{ + new_state = (blk->status & ~stateMask) | Shared; + pkt->flags |= SHARED_LINE; + return false; +} + +CoherenceProtocol::CoherenceProtocol(const string &name, + const string &protocol, + const bool doUpgrades) + : SimObject(name) +{ + if ((protocol == "mosi" || protocol == "moesi") && !doUpgrades) { + cerr << "CoherenceProtocol: ownership protocols require upgrade transactions" + << "(write miss on owned block generates ReadExcl, which will clobber dirty block)" + << endl; + fatal(""); + } + + Packet::Command writeToSharedCmd = doUpgrades ? Packet::UpgradeReq : Packet::ReadExReq; + Packet::Command writeToSharedResp = doUpgrades ? Packet::UpgradeResp : Packet::ReadExResp; + +//@todo add in hardware prefetch to this list + if (protocol == "msi") { + // incoming requests: specify outgoing bus request + transitionTable[Invalid][Packet::ReadReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::WriteReq].onRequest(Packet::ReadExReq); + transitionTable[Shared][Packet::WriteReq].onRequest(writeToSharedCmd); + //Prefetching causes a read + transitionTable[Invalid][Packet::SoftPFReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::HardPFReq].onRequest(Packet::ReadReq); + + // on response to given request: specify new state + transitionTable[Invalid][Packet::ReadResp].onResponse(Shared); + transitionTable[Invalid][Packet::ReadExResp].onResponse(Modified); + transitionTable[Shared][writeToSharedResp].onResponse(Modified); + + // bus snoop transition functions + transitionTable[Invalid][Packet::ReadReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::ReadExReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::ReadReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Modified][Packet::ReadReq].onSnoop(supplyAndGotoSharedTrans); + //Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv) + transitionTable[Invalid][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Invalid][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + + if (doUpgrades) { + transitionTable[Invalid][Packet::UpgradeReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::UpgradeReq].onSnoop(invalidateTrans); + } + } + + else if(protocol == "mesi") { + // incoming requests: specify outgoing bus request + transitionTable[Invalid][Packet::ReadReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::WriteReq].onRequest(Packet::ReadExReq); + transitionTable[Shared][Packet::WriteReq].onRequest(writeToSharedCmd); + //Prefetching causes a read + transitionTable[Invalid][Packet::SoftPFReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::HardPFReq].onRequest(Packet::ReadReq); + + // on response to given request: specify new state + transitionTable[Invalid][Packet::ReadResp].onResponse(Exclusive); + //It will move into shared if the shared line is asserted in the + //getNewState function + transitionTable[Invalid][Packet::ReadExResp].onResponse(Modified); + transitionTable[Shared][writeToSharedResp].onResponse(Modified); + + // bus snoop transition functions + transitionTable[Invalid][Packet::ReadReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::ReadExReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::ReadReq].onSnoop(assertShared); + transitionTable[Shared][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::ReadReq].onSnoop(assertShared); + transitionTable[Exclusive][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Modified][Packet::ReadReq].onSnoop(supplyAndGotoSharedTrans); + //Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv) + transitionTable[Invalid][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Invalid][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + + if (doUpgrades) { + transitionTable[Invalid][Packet::UpgradeReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::UpgradeReq].onSnoop(invalidateTrans); + } + } + + else if(protocol == "mosi") { + // incoming requests: specify outgoing bus request + transitionTable[Invalid][Packet::ReadReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::WriteReq].onRequest(Packet::ReadExReq); + transitionTable[Shared][Packet::WriteReq].onRequest(writeToSharedCmd); + transitionTable[Owned][Packet::WriteReq].onRequest(writeToSharedCmd); + //Prefetching causes a read + transitionTable[Invalid][Packet::SoftPFReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::HardPFReq].onRequest(Packet::ReadReq); + + // on response to given request: specify new state + transitionTable[Invalid][Packet::ReadResp].onResponse(Shared); + transitionTable[Invalid][Packet::ReadExResp].onResponse(Modified); + transitionTable[Shared][writeToSharedResp].onResponse(Modified); + transitionTable[Owned][writeToSharedResp].onResponse(Modified); + + // bus snoop transition functions + transitionTable[Invalid][Packet::ReadReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::ReadExReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::UpgradeReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::ReadReq].onSnoop(assertShared); + transitionTable[Shared][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::UpgradeReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Modified][Packet::ReadReq].onSnoop(supplyAndGotoOwnedTrans); + transitionTable[Owned][Packet::ReadReq].onSnoop(supplyAndGotoOwnedTrans); + transitionTable[Owned][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Owned][Packet::UpgradeReq].onSnoop(invalidateTrans); + //Tansitions on seeing a DMA (writeInv(samelevel) or DMAInv) + transitionTable[Invalid][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Owned][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Invalid][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Owned][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + } + + else if(protocol == "moesi") { + // incoming requests: specify outgoing bus request + transitionTable[Invalid][Packet::ReadReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::WriteReq].onRequest(Packet::ReadExReq); + transitionTable[Shared][Packet::WriteReq].onRequest(writeToSharedCmd); + transitionTable[Owned][Packet::WriteReq].onRequest(writeToSharedCmd); + //Prefetching causes a read + transitionTable[Invalid][Packet::SoftPFReq].onRequest(Packet::ReadReq); + transitionTable[Invalid][Packet::HardPFReq].onRequest(Packet::ReadReq); + + // on response to given request: specify new state + transitionTable[Invalid][Packet::ReadResp].onResponse(Exclusive); + //It will move into shared if the shared line is asserted in the + //getNewState function + transitionTable[Invalid][Packet::ReadExResp].onResponse(Modified); + transitionTable[Shared][writeToSharedResp].onResponse(Modified); + transitionTable[Owned][writeToSharedResp].onResponse(Modified); + + // bus snoop transition functions + transitionTable[Invalid][Packet::ReadReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::ReadExReq].onSnoop(nullTransition); + transitionTable[Invalid][Packet::UpgradeReq].onSnoop(nullTransition); + transitionTable[Shared][Packet::ReadReq].onSnoop(assertShared); + transitionTable[Shared][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::UpgradeReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::ReadReq].onSnoop(assertShared); + transitionTable[Exclusive][Packet::ReadExReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::ReadReq].onSnoop(supplyAndGotoOwnedTrans); + transitionTable[Modified][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Owned][Packet::ReadReq].onSnoop(supplyAndGotoOwnedTrans); + transitionTable[Owned][Packet::ReadExReq].onSnoop(supplyAndInvalidateTrans); + transitionTable[Owned][Packet::UpgradeReq].onSnoop(invalidateTrans); + //Transitions on seeing a DMA (writeInv(samelevel) or DMAInv) + transitionTable[Invalid][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Owned][Packet::InvalidateReq].onSnoop(invalidateTrans); + transitionTable[Invalid][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Shared][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Exclusive][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Modified][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + transitionTable[Owned][Packet::WriteInvalidateReq].onSnoop(invalidateTrans); + } + + else { + cerr << "CoherenceProtocol: unrecognized protocol " << protocol + << endl; + fatal(""); + } +} + + +Packet::Command +CoherenceProtocol::getBusCmd(Packet::Command cmdIn, CacheBlk::State state, + MSHR *mshr) +{ + state &= stateMask; + int cmd_idx = (int) cmdIn; + + assert(0 <= state && state <= stateMax); + assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS); + + Packet::Command cmdOut = transitionTable[state][cmd_idx].busCmd; + + assert(cmdOut != Packet::InvalidCmd); + + ++requestCount[state][cmd_idx]; + + return cmdOut; +} + + +CacheBlk::State +CoherenceProtocol::getNewState(Packet * &pkt, CacheBlk::State oldState) +{ + CacheBlk::State state = oldState & stateMask; + int cmd_idx = pkt->cmdToIndex(); + + assert(0 <= state && state <= stateMax); + assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS); + + CacheBlk::State newState = transitionTable[state][cmd_idx].newState; + + //Check if it's exclusive and the shared line was asserted, + //then goto shared instead + if (newState == Exclusive && (pkt->flags & SHARED_LINE)) { + newState = Shared; + } + + assert(newState != -1); + + //Make sure not to loose any other state information + newState = (oldState & ~stateMask) | newState; + return newState; +} + + +bool +CoherenceProtocol::handleBusRequest(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, + MSHR *mshr, + CacheBlk::State & new_state) +{ + if (blk == NULL) { + // nothing to do if we don't have a block + return false; + } + + CacheBlk::State state = blk->status & stateMask; + int cmd_idx = pkt->cmdToIndex(); + + assert(0 <= state && state <= stateMax); + assert(0 <= cmd_idx && cmd_idx < NUM_MEM_CMDS); + +// assert(mshr == NULL); // can't currently handle outstanding requests + //Check first if MSHR, and also insure, if there is one, that it is not in service + assert(!mshr || mshr->inService == 0); + ++snoopCount[state][cmd_idx]; + + bool ret = transitionTable[state][cmd_idx].snoopFunc(cache, pkt, blk, mshr, + new_state); + + + + return ret; +} + +bool +CoherenceProtocol::nullTransition(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, MSHR *mshr, + CacheBlk::State & new_state) +{ + // do nothing + if (blk) + new_state = blk->status; + return false; +} + + +bool +CoherenceProtocol::invalidTransition(BaseCache *cache, Packet * &pkt, + CacheBlk *blk, MSHR *mshr, + CacheBlk::State & new_state) +{ + panic("Invalid transition"); + return false; +} + +#ifndef DOXYGEN_SHOULD_SKIP_THIS + +BEGIN_DECLARE_SIM_OBJECT_PARAMS(CoherenceProtocol) + + Param<string> protocol; + Param<bool> do_upgrades; + +END_DECLARE_SIM_OBJECT_PARAMS(CoherenceProtocol) + + +BEGIN_INIT_SIM_OBJECT_PARAMS(CoherenceProtocol) + + INIT_PARAM(protocol, "name of coherence protocol"), + INIT_PARAM_DFLT(do_upgrades, "use upgrade transactions?", true) + +END_INIT_SIM_OBJECT_PARAMS(CoherenceProtocol) + + +CREATE_SIM_OBJECT(CoherenceProtocol) +{ + return new CoherenceProtocol(getInstanceName(), protocol, + do_upgrades); +} + +REGISTER_SIM_OBJECT("CoherenceProtocol", CoherenceProtocol) + +#endif // DOXYGEN_SHOULD_SKIP_THIS |