xref: /gem5/src/mem/ruby/system/Sequencer.cc

/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * 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 "base/str.hh"
#include "base/misc.hh"
#include "cpu/testers/rubytest/RubyTester.hh"
#include "mem/protocol/CacheMsg.hh"
#include "mem/protocol/Protocol.hh"
#include "mem/protocol/Protocol.hh"
#include "mem/ruby/buffers/MessageBuffer.hh"
#include "mem/ruby/common/Global.hh"
#include "mem/ruby/common/SubBlock.hh"
#include "mem/ruby/libruby.hh"
#include "mem/ruby/profiler/Profiler.hh"
#include "mem/ruby/recorder/Tracer.hh"
#include "mem/ruby/slicc_interface/AbstractController.hh"
#include "mem/ruby/system/CacheMemory.hh"
#include "mem/ruby/system/Sequencer.hh"
#include "mem/ruby/system/System.hh"
#include "mem/packet.hh"
#include "params/RubySequencer.hh"

using namespace std;

Sequencer *
RubySequencerParams::create()
{
    return new Sequencer(this);
}

Sequencer::Sequencer(const Params *p)
    : RubyPort(p), deadlockCheckEvent(this)
{
    m_store_waiting_on_load_cycles = 0;
    m_store_waiting_on_store_cycles = 0;
    m_load_waiting_on_store_cycles = 0;
    m_load_waiting_on_load_cycles = 0;

    m_outstanding_count = 0;

    m_max_outstanding_requests = 0;
    m_deadlock_threshold = 0;
    m_instCache_ptr = NULL;
    m_dataCache_ptr = NULL;

    m_instCache_ptr = p->icache;
    m_dataCache_ptr = p->dcache;
    m_max_outstanding_requests = p->max_outstanding_requests;
    m_deadlock_threshold = p->deadlock_threshold;
    m_usingRubyTester = p->using_ruby_tester;

    assert(m_max_outstanding_requests > 0);
    assert(m_deadlock_threshold > 0);
    assert(m_instCache_ptr != NULL);
    assert(m_dataCache_ptr != NULL);
}

Sequencer::~Sequencer()
{
}

void
Sequencer::wakeup()
{
    // Check for deadlock of any of the requests
    Time current_time = g_eventQueue_ptr->getTime();

    // Check across all outstanding requests
    int total_outstanding = 0;

    RequestTable::iterator read = m_readRequestTable.begin();
    RequestTable::iterator read_end = m_readRequestTable.end();
    for (; read != read_end; ++read) {
        SequencerRequest* request = read->second;
        if (current_time - request->issue_time < m_deadlock_threshold)
            continue;

        panic("Possible Deadlock detected. Aborting!\n"
             "version: %d request.paddr: %d m_readRequestTable: %d "
             "current time: %u issue_time: %d difference: %d\n", m_version,
             request->ruby_request.paddr, m_readRequestTable.size(),
             current_time, request->issue_time,
             current_time - request->issue_time);
    }

    RequestTable::iterator write = m_writeRequestTable.begin();
    RequestTable::iterator write_end = m_writeRequestTable.end();
    for (; write != write_end; ++write) {
        SequencerRequest* request = write->second;
        if (current_time - request->issue_time < m_deadlock_threshold)
            continue;

        panic("Possible Deadlock detected. Aborting!\n"
             "version: %d request.paddr: %d m_writeRequestTable: %d "
             "current time: %u issue_time: %d difference: %d\n", m_version,
             request->ruby_request.paddr, m_writeRequestTable.size(),
             current_time, request->issue_time,
             current_time - request->issue_time);
    }

    total_outstanding += m_writeRequestTable.size();
    total_outstanding += m_readRequestTable.size();

    assert(m_outstanding_count == total_outstanding);

    if (m_outstanding_count > 0) {
        // If there are still outstanding requests, keep checking
        schedule(deadlockCheckEvent,
                 m_deadlock_threshold * g_eventQueue_ptr->getClock() +
                 curTick());
    }
}

void
Sequencer::printStats(ostream & out) const
{
    out << "Sequencer: " << m_name << endl
        << "  store_waiting_on_load_cycles: "
        << m_store_waiting_on_load_cycles << endl
        << "  store_waiting_on_store_cycles: "
        << m_store_waiting_on_store_cycles << endl
        << "  load_waiting_on_load_cycles: "
        << m_load_waiting_on_load_cycles << endl
        << "  load_waiting_on_store_cycles: "
        << m_load_waiting_on_store_cycles << endl;
}

void
Sequencer::printProgress(ostream& out) const
{
#if 0
    int total_demand = 0;
    out << "Sequencer Stats Version " << m_version << endl;
    out << "Current time = " << g_eventQueue_ptr->getTime() << endl;
    out << "---------------" << endl;
    out << "outstanding requests" << endl;

    out << "proc " << m_Read
        << " version Requests = " << m_readRequestTable.size() << endl;

    // print the request table
    RequestTable::iterator read = m_readRequestTable.begin();
    RequestTable::iterator read_end = m_readRequestTable.end();
    for (; read != read_end; ++read) {
        SequencerRequest* request = read->second;
        out << "\tRequest[ " << i << " ] = " << request->type
            << " Address " << rkeys[i]
            << " Posted " << request->issue_time
            << " PF " << PrefetchBit_No << endl;
        total_demand++;
    }

    out << "proc " << m_version
        << " Write Requests = " << m_writeRequestTable.size << endl;

    // print the request table
    RequestTable::iterator write = m_writeRequestTable.begin();
    RequestTable::iterator write_end = m_writeRequestTable.end();
    for (; write != write_end; ++write) {
        SequencerRequest* request = write->second;
        out << "\tRequest[ " << i << " ] = " << request.getType()
            << " Address " << wkeys[i]
            << " Posted " << request.getTime()
            << " PF " << request.getPrefetch() << endl;
        if (request.getPrefetch() == PrefetchBit_No) {
            total_demand++;
        }
    }

    out << endl;

    out << "Total Number Outstanding: " << m_outstanding_count << endl
        << "Total Number Demand     : " << total_demand << endl
        << "Total Number Prefetches : " << m_outstanding_count - total_demand
        << endl << endl << endl;
#endif
}

void
Sequencer::printConfig(ostream& out) const
{
    out << "Seqeuncer config: " << m_name << endl
        << "  controller: " << m_controller->getName() << endl
        << "  version: " << m_version << endl
        << "  max_outstanding_requests: " << m_max_outstanding_requests << endl
        << "  deadlock_threshold: " << m_deadlock_threshold << endl;
}

// Insert the request on the correct request table.  Return true if
// the entry was already present.
bool
Sequencer::insertRequest(SequencerRequest* request)
{
    int total_outstanding =
        m_writeRequestTable.size() + m_readRequestTable.size();

    assert(m_outstanding_count == total_outstanding);

    // See if we should schedule a deadlock check
    if (deadlockCheckEvent.scheduled() == false) {
        schedule(deadlockCheckEvent, m_deadlock_threshold + curTick());
    }

    Address line_addr(request->ruby_request.paddr);
    line_addr.makeLineAddress();
    if ((request->ruby_request.type == RubyRequestType_ST) ||
        (request->ruby_request.type == RubyRequestType_RMW_Read) ||
        (request->ruby_request.type == RubyRequestType_RMW_Write) ||
        (request->ruby_request.type == RubyRequestType_Load_Linked) ||
        (request->ruby_request.type == RubyRequestType_Store_Conditional) ||
        (request->ruby_request.type == RubyRequestType_Locked_RMW_Read) ||
        (request->ruby_request.type == RubyRequestType_Locked_RMW_Write)) {
        pair<RequestTable::iterator, bool> r =
            m_writeRequestTable.insert(RequestTable::value_type(line_addr, 0));
        bool success = r.second;
        RequestTable::iterator i = r.first;
        if (!success) {
            i->second = request;
            // return true;

            // drh5: isn't this an error?  do you lose the initial request?
            assert(0);
        }
        i->second = request;
        m_outstanding_count++;
    } else {
        pair<RequestTable::iterator, bool> r =
            m_readRequestTable.insert(RequestTable::value_type(line_addr, 0));
        bool success = r.second;
        RequestTable::iterator i = r.first;
        if (!success) {
            i->second = request;
            // return true;

            // drh5: isn't this an error?  do you lose the initial request?
            assert(0);
        }
        i->second = request;
        m_outstanding_count++;
    }

    g_system_ptr->getProfiler()->sequencerRequests(m_outstanding_count);

    total_outstanding = m_writeRequestTable.size() + m_readRequestTable.size();
    assert(m_outstanding_count == total_outstanding);

    return false;
}

void
Sequencer::markRemoved()
{
    m_outstanding_count--;
    assert(m_outstanding_count ==
           m_writeRequestTable.size() + m_readRequestTable.size());
}

void
Sequencer::removeRequest(SequencerRequest* srequest)
{
    assert(m_outstanding_count ==
           m_writeRequestTable.size() + m_readRequestTable.size());

    const RubyRequest & ruby_request = srequest->ruby_request;
    Address line_addr(ruby_request.paddr);
    line_addr.makeLineAddress();
    if ((ruby_request.type == RubyRequestType_ST) ||
        (ruby_request.type == RubyRequestType_RMW_Read) ||
        (ruby_request.type == RubyRequestType_RMW_Write) ||
        (ruby_request.type == RubyRequestType_Load_Linked) ||
        (ruby_request.type == RubyRequestType_Store_Conditional) ||
        (ruby_request.type == RubyRequestType_Locked_RMW_Read) ||
        (ruby_request.type == RubyRequestType_Locked_RMW_Write)) {
        m_writeRequestTable.erase(line_addr);
    } else {
        m_readRequestTable.erase(line_addr);
    }

    markRemoved();
}

bool
Sequencer::handleLlsc(const Address& address, SequencerRequest* request)
{
    //
    // The success flag indicates whether the LLSC operation was successful.
    // LL ops will always succeed, but SC may fail if the cache line is no
    // longer locked.
    //
    bool success = true;
    if (request->ruby_request.type == RubyRequestType_Store_Conditional) {
        if (!m_dataCache_ptr->isLocked(address, m_version)) {
            //
            // For failed SC requests, indicate the failure to the cpu by
            // setting the extra data to zero.
            //
            request->ruby_request.pkt->req->setExtraData(0);
            success = false;
        } else {
            //
            // For successful SC requests, indicate the success to the cpu by
            // setting the extra data to one.
            //
            request->ruby_request.pkt->req->setExtraData(1);
        }
        //
        // Independent of success, all SC operations must clear the lock
        //
        m_dataCache_ptr->clearLocked(address);
    } else if (request->ruby_request.type == RubyRequestType_Load_Linked) {
        //
        // Note: To fully follow Alpha LLSC semantics, should the LL clear any
        // previously locked cache lines?
        //
        m_dataCache_ptr->setLocked(address, m_version);
    } else if (m_dataCache_ptr->isLocked(address, m_version)) {
        //
        // Normal writes should clear the locked address
        //
        m_dataCache_ptr->clearLocked(address);
    }
    return success;
}

void
Sequencer::writeCallback(const Address& address, DataBlock& data)
{
    writeCallback(address, GenericMachineType_NULL, data);
}

void
Sequencer::writeCallback(const Address& address,
                         GenericMachineType mach,
                         DataBlock& data)
{
    writeCallback(address, mach, data, 0, 0, 0);
}

void
Sequencer::writeCallback(const Address& address,
                         GenericMachineType mach,
                         DataBlock& data,
                         Time initialRequestTime,
                         Time forwardRequestTime,
                         Time firstResponseTime)
{
    assert(address == line_address(address));
    assert(m_writeRequestTable.count(line_address(address)));

    RequestTable::iterator i = m_writeRequestTable.find(address);
    assert(i != m_writeRequestTable.end());
    SequencerRequest* request = i->second;

    m_writeRequestTable.erase(i);
    markRemoved();

    assert((request->ruby_request.type == RubyRequestType_ST) ||
           (request->ruby_request.type == RubyRequestType_RMW_Read) ||
           (request->ruby_request.type == RubyRequestType_RMW_Write) ||
           (request->ruby_request.type == RubyRequestType_Load_Linked) ||
           (request->ruby_request.type == RubyRequestType_Store_Conditional) ||
           (request->ruby_request.type == RubyRequestType_Locked_RMW_Read) ||
           (request->ruby_request.type == RubyRequestType_Locked_RMW_Write));

    //
    // For Alpha, properly handle LL, SC, and write requests with respect to
    // locked cache blocks.
    //
    bool success = handleLlsc(address, request);

    if (request->ruby_request.type == RubyRequestType_Locked_RMW_Read) {
        m_controller->blockOnQueue(address, m_mandatory_q_ptr);
    } else if (request->ruby_request.type == RubyRequestType_Locked_RMW_Write) {
        m_controller->unblock(address);
    }

    hitCallback(request, mach, data, success,
                initialRequestTime, forwardRequestTime, firstResponseTime);
}

void
Sequencer::readCallback(const Address& address, DataBlock& data)
{
    readCallback(address, GenericMachineType_NULL, data);
}

void
Sequencer::readCallback(const Address& address,
                        GenericMachineType mach,
                        DataBlock& data)
{
    readCallback(address, mach, data, 0, 0, 0);
}

void
Sequencer::readCallback(const Address& address,
                        GenericMachineType mach,
                        DataBlock& data,
                        Time initialRequestTime,
                        Time forwardRequestTime,
                        Time firstResponseTime)
{
    assert(address == line_address(address));
    assert(m_readRequestTable.count(line_address(address)));

    RequestTable::iterator i = m_readRequestTable.find(address);
    assert(i != m_readRequestTable.end());
    SequencerRequest* request = i->second;

    m_readRequestTable.erase(i);
    markRemoved();

    assert((request->ruby_request.type == RubyRequestType_LD) ||
           (request->ruby_request.type == RubyRequestType_IFETCH));

    hitCallback(request, mach, data, true,
                initialRequestTime, forwardRequestTime, firstResponseTime);
}

void
Sequencer::hitCallback(SequencerRequest* srequest,
                       GenericMachineType mach,
                       DataBlock& data,
                       bool success,
                       Time initialRequestTime,
                       Time forwardRequestTime,
                       Time firstResponseTime)
{
    const RubyRequest & ruby_request = srequest->ruby_request;
    Address request_address(ruby_request.paddr);
    Address request_line_address(ruby_request.paddr);
    request_line_address.makeLineAddress();
    RubyRequestType type = ruby_request.type;
    Time issued_time = srequest->issue_time;

    // Set this cache entry to the most recently used
    if (type == RubyRequestType_IFETCH) {
        if (m_instCache_ptr->isTagPresent(request_line_address))
            m_instCache_ptr->setMRU(request_line_address);
    } else {
        if (m_dataCache_ptr->isTagPresent(request_line_address))
            m_dataCache_ptr->setMRU(request_line_address);
    }

    assert(g_eventQueue_ptr->getTime() >= issued_time);
    Time miss_latency = g_eventQueue_ptr->getTime() - issued_time;

    // Profile the miss latency for all non-zero demand misses
    if (miss_latency != 0) {
        g_system_ptr->getProfiler()->missLatency(miss_latency, type, mach);

        if (mach == GenericMachineType_L1Cache_wCC) {
            g_system_ptr->getProfiler()->missLatencyWcc(issued_time,
                                                   initialRequestTime,
                                                   forwardRequestTime,
                                                   firstResponseTime,
                                                   g_eventQueue_ptr->getTime());
        }

        if (mach == GenericMachineType_Directory) {
            g_system_ptr->getProfiler()->missLatencyDir(issued_time,
                                                   initialRequestTime,
                                                   forwardRequestTime,
                                                   firstResponseTime,
                                                   g_eventQueue_ptr->getTime());
        }

        DPRINTFR(ProtocolTrace, "%7s %3s %10s%20s %6s>%-6s %s %d cycles\n",
            g_eventQueue_ptr->getTime(), m_version, "Seq",
            success ? "Done" : "SC_Failed", "", "",
            Address(ruby_request.paddr), miss_latency);
    }
#if 0
    if (request.getPrefetch() == PrefetchBit_Yes) {
        return; // Ignore the prefetch
    }
#endif

    // update the data
    if (ruby_request.data != NULL) {
        if ((type == RubyRequestType_LD) ||
            (type == RubyRequestType_IFETCH) ||
            (type == RubyRequestType_RMW_Read) ||
            (type == RubyRequestType_Locked_RMW_Read) ||
            (type == RubyRequestType_Load_Linked)) {
            memcpy(ruby_request.data,
                   data.getData(request_address.getOffset(), ruby_request.len),
                   ruby_request.len);
        } else {
            data.setData(ruby_request.data, request_address.getOffset(),
                         ruby_request.len);
        }
    } else {
        DPRINTF(MemoryAccess,
                "WARNING.  Data not transfered from Ruby to M5 for type %s\n",
                RubyRequestType_to_string(type));
    }

    // If using the RubyTester, update the RubyTester sender state's
    // subBlock with the recieved data.  The tester will later access
    // this state.
    // Note: RubyPort will access it's sender state before the
    // RubyTester.
    if (m_usingRubyTester) {
        RubyPort::SenderState *requestSenderState =
            safe_cast<RubyPort::SenderState*>(ruby_request.pkt->senderState);
        RubyTester::SenderState* testerSenderState =
            safe_cast<RubyTester::SenderState*>(requestSenderState->saved);
        testerSenderState->subBlock->mergeFrom(data);
    }

    ruby_hit_callback(ruby_request.pkt);
    delete srequest;
}

// Returns true if the sequencer already has a load or store outstanding
RequestStatus
Sequencer::getRequestStatus(const RubyRequest& request)
{
    bool is_outstanding_store =
        !!m_writeRequestTable.count(line_address(Address(request.paddr)));
    bool is_outstanding_load =
        !!m_readRequestTable.count(line_address(Address(request.paddr)));
    if (is_outstanding_store) {
        if ((request.type == RubyRequestType_LD) ||
            (request.type == RubyRequestType_IFETCH) ||
            (request.type == RubyRequestType_RMW_Read)) {
            m_store_waiting_on_load_cycles++;
        } else {
            m_store_waiting_on_store_cycles++;
        }
        return RequestStatus_Aliased;
    } else if (is_outstanding_load) {
        if ((request.type == RubyRequestType_ST) ||
            (request.type == RubyRequestType_RMW_Write)) {
            m_load_waiting_on_store_cycles++;
        } else {
            m_load_waiting_on_load_cycles++;
        }
        return RequestStatus_Aliased;
    }

    if (m_outstanding_count >= m_max_outstanding_requests) {
        return RequestStatus_BufferFull;
    }

    return RequestStatus_Ready;
}

bool
Sequencer::empty() const
{
    return m_writeRequestTable.empty() && m_readRequestTable.empty();
}

RequestStatus
Sequencer::makeRequest(const RubyRequest &request)
{
    assert(Address(request.paddr).getOffset() + request.len <=
           RubySystem::getBlockSizeBytes());
    RequestStatus status = getRequestStatus(request);
    if (status != RequestStatus_Ready)
        return status;

    SequencerRequest *srequest =
        new SequencerRequest(request, g_eventQueue_ptr->getTime());
    bool found = insertRequest(srequest);
    if (found) {
        panic("Sequencer::makeRequest should never be called if the "
              "request is already outstanding\n");
        return RequestStatus_NULL;
    }

    issueRequest(request);

    // TODO: issue hardware prefetches here
    return RequestStatus_Issued;
}

void
Sequencer::issueRequest(const RubyRequest& request)
{
    // TODO: get rid of CacheMsg, CacheRequestType, and
    // AccessModeTYpe, & have SLICC use RubyRequest and subtypes
    // natively
    CacheRequestType ctype;
    switch(request.type) {
      case RubyRequestType_IFETCH:
        ctype = CacheRequestType_IFETCH;
        break;
      case RubyRequestType_LD:
        ctype = CacheRequestType_LD;
        break;
      case RubyRequestType_ST:
      case RubyRequestType_RMW_Read:
      case RubyRequestType_RMW_Write:
      //
      // x86 locked instructions are translated to store cache coherence
      // requests because these requests should always be treated as read
      // exclusive operations and should leverage any migratory sharing
      // optimization built into the protocol.
      //
      case RubyRequestType_Locked_RMW_Read:
      case RubyRequestType_Locked_RMW_Write:
        ctype = CacheRequestType_ST;
        break;
      //
      // Alpha LL/SC instructions need to be handled carefully by the cache
      // coherence protocol to ensure they follow the proper semantics.  In
      // particular, by identifying the operations as atomic, the protocol
      // should understand that migratory sharing optimizations should not be
      // performed (i.e. a load between the LL and SC should not steal away
      // exclusive permission).
      //
      case RubyRequestType_Load_Linked:
      case RubyRequestType_Store_Conditional:
        ctype = CacheRequestType_ATOMIC;
        break;
      default:
        assert(0);
    }

    AccessModeType amtype;
    switch(request.access_mode){
      case RubyAccessMode_User:
        amtype = AccessModeType_UserMode;
        break;
      case RubyAccessMode_Supervisor:
        amtype = AccessModeType_SupervisorMode;
        break;
      case RubyAccessMode_Device:
        amtype = AccessModeType_UserMode;
        break;
      default:
        assert(0);
    }

    Address line_addr(request.paddr);
    line_addr.makeLineAddress();
    CacheMsg *msg = new CacheMsg(line_addr, Address(request.paddr), ctype,
        Address(request.pc), amtype, request.len, PrefetchBit_No,
        request.proc_id);

    DPRINTFR(ProtocolTrace, "%7s %3s %10s%20s %6s>%-6s %s %s\n",
        g_eventQueue_ptr->getTime(), m_version, "Seq", "Begin", "", "",
        Address(request.paddr), RubyRequestType_to_string(request.type));

    Time latency = 0;  // initialzed to an null value

    if (request.type == RubyRequestType_IFETCH)
        latency = m_instCache_ptr->getLatency();
    else
        latency = m_dataCache_ptr->getLatency();

    // Send the message to the cache controller
    assert(latency > 0);

    assert(m_mandatory_q_ptr != NULL);
    m_mandatory_q_ptr->enqueue(msg, latency);
}

#if 0
bool
Sequencer::tryCacheAccess(const Address& addr, CacheRequestType type,
                          AccessModeType access_mode,
                          int size, DataBlock*& data_ptr)
{
    CacheMemory *cache =
        (type == CacheRequestType_IFETCH) ? m_instCache_ptr : m_dataCache_ptr;

    return cache->tryCacheAccess(line_address(addr), type, data_ptr);
}
#endif

template <class KEY, class VALUE>
std::ostream &
operator<<(ostream &out, const m5::hash_map<KEY, VALUE> &map)
{
    typename m5::hash_map<KEY, VALUE>::const_iterator i = map.begin();
    typename m5::hash_map<KEY, VALUE>::const_iterator end = map.end();

    out << "[";
    for (; i != end; ++i)
        out << " " << i->first << "=" << i->second;
    out << " ]";

    return out;
}

void
Sequencer::print(ostream& out) const
{
    out << "[Sequencer: " << m_version
        << ", outstanding requests: " << m_outstanding_count
        << ", read request table: " << m_readRequestTable
        << ", write request table: " << m_writeRequestTable
        << "]";
}

// this can be called from setState whenever coherence permissions are
// upgraded when invoked, coherence violations will be checked for the
// given block
void
Sequencer::checkCoherence(const Address& addr)
{
#ifdef CHECK_COHERENCE
    g_system_ptr->checkGlobalCoherenceInvariant(addr);
#endif
}