gem5/src/mem/port.cc
Andreas Hansson f26a289295 mem: Split port retry for all different packet classes
This patch fixes a long-standing isue with the port flow
control. Before this patch the retry mechanism was shared between all
different packet classes. As a result, a snoop response could get
stuck behind a request waiting for a retry, even if the send/recv
functions were split. This caused message-dependent deadlocks in
stress-test scenarios.

The patch splits the retry into one per packet (message) class. Thus,
sendTimingReq has a corresponding recvReqRetry, sendTimingResp has
recvRespRetry etc. Most of the changes to the code involve simply
clarifying what type of request a specific object was accepting.

The biggest change in functionality is in the cache downstream packet
queue, facing the memory. This queue was shared by requests and snoop
responses, and it is now split into two queues, each with their own
flow control, but the same physical MasterPort. These changes fixes
the previously seen deadlocks.
2015-03-02 04:00:35 -05:00

274 lines
6.5 KiB
C++

/*
* Copyright (c) 2012,2015 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* 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: Steve Reinhardt
* Andreas Hansson
* William Wang
*/
/**
* @file
* Port object definitions.
*/
#include "base/trace.hh"
#include "mem/mem_object.hh"
#include "mem/port.hh"
Port::Port(const std::string &_name, MemObject& _owner, PortID _id)
: portName(_name), id(_id), owner(_owner)
{
}
Port::~Port()
{
}
BaseMasterPort::BaseMasterPort(const std::string& name, MemObject* owner,
PortID _id)
: Port(name, *owner, _id), _baseSlavePort(NULL)
{
}
BaseMasterPort::~BaseMasterPort()
{
}
BaseSlavePort&
BaseMasterPort::getSlavePort() const
{
if(_baseSlavePort == NULL)
panic("Cannot getSlavePort on master port %s that is not connected\n",
name());
return *_baseSlavePort;
}
bool
BaseMasterPort::isConnected() const
{
return _baseSlavePort != NULL;
}
BaseSlavePort::BaseSlavePort(const std::string& name, MemObject* owner,
PortID _id)
: Port(name, *owner, _id), _baseMasterPort(NULL)
{
}
BaseSlavePort::~BaseSlavePort()
{
}
BaseMasterPort&
BaseSlavePort::getMasterPort() const
{
if(_baseMasterPort == NULL)
panic("Cannot getMasterPort on slave port %s that is not connected\n",
name());
return *_baseMasterPort;
}
bool
BaseSlavePort::isConnected() const
{
return _baseMasterPort != NULL;
}
/**
* Master port
*/
MasterPort::MasterPort(const std::string& name, MemObject* owner, PortID _id)
: BaseMasterPort(name, owner, _id), _slavePort(NULL)
{
}
MasterPort::~MasterPort()
{
}
void
MasterPort::bind(BaseSlavePort& slave_port)
{
// bind on the level of the base ports
_baseSlavePort = &slave_port;
// also attempt to base the slave to the appropriate type
SlavePort* cast_slave_port = dynamic_cast<SlavePort*>(&slave_port);
// if this port is compatible, then proceed with the binding
if (cast_slave_port != NULL) {
// master port keeps track of the slave port
_slavePort = cast_slave_port;
// slave port also keeps track of master port
_slavePort->bind(*this);
} else {
fatal("Master port %s cannot bind to %s\n", name(),
slave_port.name());
}
}
void
MasterPort::unbind()
{
if (_slavePort == NULL)
panic("Attempting to unbind master port %s that is not connected\n",
name());
_slavePort->unbind();
_slavePort = NULL;
_baseSlavePort = NULL;
}
AddrRangeList
MasterPort::getAddrRanges() const
{
return _slavePort->getAddrRanges();
}
Tick
MasterPort::sendAtomic(PacketPtr pkt)
{
assert(pkt->isRequest());
return _slavePort->recvAtomic(pkt);
}
void
MasterPort::sendFunctional(PacketPtr pkt)
{
assert(pkt->isRequest());
return _slavePort->recvFunctional(pkt);
}
bool
MasterPort::sendTimingReq(PacketPtr pkt)
{
assert(pkt->isRequest());
return _slavePort->recvTimingReq(pkt);
}
bool
MasterPort::sendTimingSnoopResp(PacketPtr pkt)
{
assert(pkt->isResponse());
return _slavePort->recvTimingSnoopResp(pkt);
}
void
MasterPort::sendRetryResp()
{
_slavePort->recvRespRetry();
}
void
MasterPort::printAddr(Addr a)
{
Request req(a, 1, 0, Request::funcMasterId);
Packet pkt(&req, MemCmd::PrintReq);
Packet::PrintReqState prs(std::cerr);
pkt.senderState = &prs;
sendFunctional(&pkt);
}
/**
* Slave port
*/
SlavePort::SlavePort(const std::string& name, MemObject* owner, PortID id)
: BaseSlavePort(name, owner, id), _masterPort(NULL)
{
}
SlavePort::~SlavePort()
{
}
void
SlavePort::unbind()
{
_baseMasterPort = NULL;
_masterPort = NULL;
}
void
SlavePort::bind(MasterPort& master_port)
{
_baseMasterPort = &master_port;
_masterPort = &master_port;
}
Tick
SlavePort::sendAtomicSnoop(PacketPtr pkt)
{
assert(pkt->isRequest());
return _masterPort->recvAtomicSnoop(pkt);
}
void
SlavePort::sendFunctionalSnoop(PacketPtr pkt)
{
assert(pkt->isRequest());
return _masterPort->recvFunctionalSnoop(pkt);
}
bool
SlavePort::sendTimingResp(PacketPtr pkt)
{
assert(pkt->isResponse());
return _masterPort->recvTimingResp(pkt);
}
void
SlavePort::sendTimingSnoopReq(PacketPtr pkt)
{
assert(pkt->isRequest());
_masterPort->recvTimingSnoopReq(pkt);
}
void
SlavePort::sendRetryReq()
{
_masterPort->recvReqRetry();
}
void
SlavePort::sendRetrySnoopResp()
{
_masterPort->recvRetrySnoopResp();
}