src/mem/noncoherent_xbar.cc - public/gem5 - Git at Google

 /*
  * Copyright (c) 2011-2015, 2018-2019 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) 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.
  */

 /**
  * @file
  * Definition of a non-coherent crossbar object.
  */

 #include "mem/noncoherent_xbar.hh"

 #include "base/logging.hh"
 #include "base/trace.hh"
 #include "debug/NoncoherentXBar.hh"
 #include "debug/XBar.hh"

 namespace gem5
 {

 NoncoherentXBar::NoncoherentXBar(const NoncoherentXBarParams &p)
     : BaseXBar(p)
 {
     // create the ports based on the size of the memory-side port and
     // CPU-side port vector ports, and the presence of the default port,
     // the ports are enumerated starting from zero
     for (int i = 0; i < p.port_mem_side_ports_connection_count; ++i) {
         std::string portName = csprintf("%s.mem_side_port[%d]", name(), i);
         RequestPort* bp = new NoncoherentXBarRequestPort(portName, *this, i);
         memSidePorts.push_back(bp);
         reqLayers.push_back(new ReqLayer(*bp, *this,
                                          csprintf("reqLayer%d", i)));
     }

     // see if we have a default CPU-side-port device connected and if so add
     // our corresponding memory-side port
     if (p.port_default_connection_count) {
         defaultPortID = memSidePorts.size();
         std::string portName = name() + ".default";
         RequestPort* bp = new NoncoherentXBarRequestPort(portName, *this,
                                                       defaultPortID);
         memSidePorts.push_back(bp);
         reqLayers.push_back(new ReqLayer(*bp, *this, csprintf("reqLayer%d",
                                                               defaultPortID)));
     }

     // create the CPU-side ports, once again starting at zero
     for (int i = 0; i < p.port_cpu_side_ports_connection_count; ++i) {
         std::string portName = csprintf("%s.cpu_side_ports[%d]", name(), i);
         QueuedResponsePort* bp = new NoncoherentXBarResponsePort(portName,
                                                                 *this, i);
         cpuSidePorts.push_back(bp);
         respLayers.push_back(new RespLayer(*bp, *this,
                                            csprintf("respLayer%d", i)));
     }
 }

 NoncoherentXBar::~NoncoherentXBar()
 {
     for (auto l: reqLayers)
         delete l;
     for (auto l: respLayers)
         delete l;
 }

 bool
 NoncoherentXBar::recvTimingReq(PacketPtr pkt, PortID cpu_side_port_id)
 {
     // determine the source port based on the id
     ResponsePort *src_port = cpuSidePorts[cpu_side_port_id];

     // we should never see express snoops on a non-coherent crossbar
     assert(!pkt->isExpressSnoop());

     // determine the destination based on the address
     PortID mem_side_port_id = findPort(pkt->getAddrRange());

     // test if the layer should be considered occupied for the current
     // port
     if (!reqLayers[mem_side_port_id]->tryTiming(src_port)) {
         DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x BUSY\n",
                 src_port->name(), pkt->cmdString(), pkt->getAddr());
         return false;
     }

     DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x\n",
             src_port->name(), pkt->cmdString(), pkt->getAddr());

     // store size and command as they might be modified when
     // forwarding the packet
     unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
     unsigned int pkt_cmd = pkt->cmdToIndex();

     // store the old header delay so we can restore it if needed
     Tick old_header_delay = pkt->headerDelay;

     // a request sees the frontend and forward latency
     Tick xbar_delay = (frontendLatency + forwardLatency) * clockPeriod();

     // set the packet header and payload delay
     calcPacketTiming(pkt, xbar_delay);

     // determine how long to be crossbar layer is busy
     Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;

     // before forwarding the packet (and possibly altering it),
     // remember if we are expecting a response
     const bool expect_response = pkt->needsResponse() &&
         !pkt->cacheResponding();

     // since it is a normal request, attempt to send the packet
     bool success = memSidePorts[mem_side_port_id]->sendTimingReq(pkt);

     if (!success)  {
         DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x RETRY\n",
                 src_port->name(), pkt->cmdString(), pkt->getAddr());

         // restore the header delay as it is additive
         pkt->headerDelay = old_header_delay;

         // occupy until the header is sent
         reqLayers[mem_side_port_id]->failedTiming(src_port,
                                                 clockEdge(Cycles(1)));

         return false;
     }

     // remember where to route the response to
     if (expect_response) {
         assert(routeTo.find(pkt->req) == routeTo.end());
         routeTo[pkt->req] = cpu_side_port_id;
     }

     reqLayers[mem_side_port_id]->succeededTiming(packetFinishTime);

     // stats updates
     pktCount[cpu_side_port_id][mem_side_port_id]++;
     pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
     transDist[pkt_cmd]++;

     return true;
 }

 bool
 NoncoherentXBar::recvTimingResp(PacketPtr pkt, PortID mem_side_port_id)
 {
     // determine the source port based on the id
     RequestPort *src_port = memSidePorts[mem_side_port_id];

     // determine the destination
     const auto route_lookup = routeTo.find(pkt->req);
     assert(route_lookup != routeTo.end());
     const PortID cpu_side_port_id = route_lookup->second;
     assert(cpu_side_port_id != InvalidPortID);
     assert(cpu_side_port_id < respLayers.size());

     // test if the layer should be considered occupied for the current
     // port
     if (!respLayers[cpu_side_port_id]->tryTiming(src_port)) {
         DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x BUSY\n",
                 src_port->name(), pkt->cmdString(), pkt->getAddr());
         return false;
     }

     DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x\n",
             src_port->name(), pkt->cmdString(), pkt->getAddr());

     // store size and command as they might be modified when
     // forwarding the packet
     unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
     unsigned int pkt_cmd = pkt->cmdToIndex();

     // a response sees the response latency
     Tick xbar_delay = responseLatency * clockPeriod();

     // set the packet header and payload delay
     calcPacketTiming(pkt, xbar_delay);

     // determine how long to be crossbar layer is busy
     Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;

     // send the packet through the destination CPU-side port, and pay for
     // any outstanding latency
     Tick latency = pkt->headerDelay;
     pkt->headerDelay = 0;
     cpuSidePorts[cpu_side_port_id]->schedTimingResp(pkt,
                                         curTick() + latency);

     // remove the request from the routing table
     routeTo.erase(route_lookup);

     respLayers[cpu_side_port_id]->succeededTiming(packetFinishTime);

     // stats updates
     pktCount[cpu_side_port_id][mem_side_port_id]++;
     pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
     transDist[pkt_cmd]++;

     return true;
 }

 void
 NoncoherentXBar::recvReqRetry(PortID mem_side_port_id)
 {
     // responses never block on forwarding them, so the retry will
     // always be coming from a port to which we tried to forward a
     // request
     reqLayers[mem_side_port_id]->recvRetry();
 }

 Tick
 NoncoherentXBar::recvAtomicBackdoor(PacketPtr pkt, PortID cpu_side_port_id,
                                     MemBackdoorPtr *backdoor)
 {
     DPRINTF(NoncoherentXBar, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
             cpuSidePorts[cpu_side_port_id]->name(), pkt->getAddr(),
             pkt->cmdString());

     unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
     unsigned int pkt_cmd = pkt->cmdToIndex();

     // determine the destination port
     PortID mem_side_port_id = findPort(pkt->getAddrRange());

     // stats updates for the request
     pktCount[cpu_side_port_id][mem_side_port_id]++;
     pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
     transDist[pkt_cmd]++;

     // forward the request to the appropriate destination
     auto mem_side_port = memSidePorts[mem_side_port_id];
     Tick response_latency = backdoor ?
         mem_side_port->sendAtomicBackdoor(pkt, *backdoor) :
         mem_side_port->sendAtomic(pkt);

     // add the response data
     if (pkt->isResponse()) {
         pkt_size = pkt->hasData() ? pkt->getSize() : 0;
         pkt_cmd = pkt->cmdToIndex();

         // stats updates
         pktCount[cpu_side_port_id][mem_side_port_id]++;
         pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
         transDist[pkt_cmd]++;
     }

     // @todo: Not setting first-word time
     pkt->payloadDelay = response_latency;
     return response_latency;
 }

 void
 NoncoherentXBar::recvMemBackdoorReq(const MemBackdoorReq &req,
         MemBackdoorPtr &backdoor)
 {
     PortID dest_id = findPort(req.range());
     memSidePorts[dest_id]->sendMemBackdoorReq(req, backdoor);
 }

 void
 NoncoherentXBar::recvFunctional(PacketPtr pkt, PortID cpu_side_port_id)
 {
     if (!pkt->isPrint()) {
         // don't do DPRINTFs on PrintReq as it clutters up the output
         DPRINTF(NoncoherentXBar,
                 "recvFunctional: packet src %s addr 0x%x cmd %s\n",
                 cpuSidePorts[cpu_side_port_id]->name(), pkt->getAddr(),
                 pkt->cmdString());
     }

     // since our CPU-side ports are queued ports we need to check them as well
     for (const auto& p : cpuSidePorts) {
         // if we find a response that has the data, then the
         // downstream caches/memories may be out of date, so simply stop
         // here
         if (p->trySatisfyFunctional(pkt)) {
             if (pkt->needsResponse())
                 pkt->makeResponse();
             return;
         }
     }

     // determine the destination port
     PortID dest_id = findPort(pkt->getAddrRange());

     // forward the request to the appropriate destination
     memSidePorts[dest_id]->sendFunctional(pkt);
 }

 } // namespace gem5
	/*
	* Copyright (c) 2011-2015, 2018-2019 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) 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.
	*/

	/**
	* @file
	* Definition of a non-coherent crossbar object.
	*/

	#include "mem/noncoherent_xbar.hh"

	#include "base/logging.hh"
	#include "base/trace.hh"
	#include "debug/NoncoherentXBar.hh"
	#include "debug/XBar.hh"

	namespace gem5
	{

	NoncoherentXBar::NoncoherentXBar(const NoncoherentXBarParams &p)
	: BaseXBar(p)
	{
	// create the ports based on the size of the memory-side port and
	// CPU-side port vector ports, and the presence of the default port,
	// the ports are enumerated starting from zero
	for (int i = 0; i < p.port_mem_side_ports_connection_count; ++i) {
	std::string portName = csprintf("%s.mem_side_port[%d]", name(), i);
	RequestPort* bp = new NoncoherentXBarRequestPort(portName, *this, i);
	memSidePorts.push_back(bp);
	reqLayers.push_back(new ReqLayer(bp, this,
	csprintf("reqLayer%d", i)));
	}

	// see if we have a default CPU-side-port device connected and if so add
	// our corresponding memory-side port
	if (p.port_default_connection_count) {
	defaultPortID = memSidePorts.size();
	std::string portName = name() + ".default";
	RequestPort* bp = new NoncoherentXBarRequestPort(portName, *this,
	defaultPortID);
	memSidePorts.push_back(bp);
	reqLayers.push_back(new ReqLayer(bp, this, csprintf("reqLayer%d",
	defaultPortID)));
	}

	// create the CPU-side ports, once again starting at zero
	for (int i = 0; i < p.port_cpu_side_ports_connection_count; ++i) {
	std::string portName = csprintf("%s.cpu_side_ports[%d]", name(), i);
	QueuedResponsePort* bp = new NoncoherentXBarResponsePort(portName,
	*this, i);
	cpuSidePorts.push_back(bp);
	respLayers.push_back(new RespLayer(bp, this,
	csprintf("respLayer%d", i)));
	}
	}

	NoncoherentXBar::~NoncoherentXBar()
	{
	for (auto l: reqLayers)
	delete l;
	for (auto l: respLayers)
	delete l;
	}

	bool
	NoncoherentXBar::recvTimingReq(PacketPtr pkt, PortID cpu_side_port_id)
	{
	// determine the source port based on the id
	ResponsePort *src_port = cpuSidePorts[cpu_side_port_id];

	// we should never see express snoops on a non-coherent crossbar
	assert(!pkt->isExpressSnoop());

	// determine the destination based on the address
	PortID mem_side_port_id = findPort(pkt->getAddrRange());

	// test if the layer should be considered occupied for the current
	// port
	if (!reqLayers[mem_side_port_id]->tryTiming(src_port)) {
	DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x BUSY\n",
	src_port->name(), pkt->cmdString(), pkt->getAddr());
	return false;
	}

	DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x\n",
	src_port->name(), pkt->cmdString(), pkt->getAddr());

	// store size and command as they might be modified when
	// forwarding the packet
	unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
	unsigned int pkt_cmd = pkt->cmdToIndex();

	// store the old header delay so we can restore it if needed
	Tick old_header_delay = pkt->headerDelay;

	// a request sees the frontend and forward latency
	Tick xbar_delay = (frontendLatency + forwardLatency) * clockPeriod();

	// set the packet header and payload delay
	calcPacketTiming(pkt, xbar_delay);

	// determine how long to be crossbar layer is busy
	Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;

	// before forwarding the packet (and possibly altering it),
	// remember if we are expecting a response
	const bool expect_response = pkt->needsResponse() &&
	!pkt->cacheResponding();

	// since it is a normal request, attempt to send the packet
	bool success = memSidePorts[mem_side_port_id]->sendTimingReq(pkt);

	if (!success) {
	DPRINTF(NoncoherentXBar, "recvTimingReq: src %s %s 0x%x RETRY\n",
	src_port->name(), pkt->cmdString(), pkt->getAddr());

	// restore the header delay as it is additive
	pkt->headerDelay = old_header_delay;

	// occupy until the header is sent
	reqLayers[mem_side_port_id]->failedTiming(src_port,
	clockEdge(Cycles(1)));

	return false;
	}

	// remember where to route the response to
	if (expect_response) {
	assert(routeTo.find(pkt->req) == routeTo.end());
	routeTo[pkt->req] = cpu_side_port_id;
	}

	reqLayers[mem_side_port_id]->succeededTiming(packetFinishTime);

	// stats updates
	pktCount[cpu_side_port_id][mem_side_port_id]++;
	pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
	transDist[pkt_cmd]++;

	return true;
	}

	bool
	NoncoherentXBar::recvTimingResp(PacketPtr pkt, PortID mem_side_port_id)
	{
	// determine the source port based on the id
	RequestPort *src_port = memSidePorts[mem_side_port_id];

	// determine the destination
	const auto route_lookup = routeTo.find(pkt->req);
	assert(route_lookup != routeTo.end());
	const PortID cpu_side_port_id = route_lookup->second;
	assert(cpu_side_port_id != InvalidPortID);
	assert(cpu_side_port_id < respLayers.size());

	// test if the layer should be considered occupied for the current
	// port
	if (!respLayers[cpu_side_port_id]->tryTiming(src_port)) {
	DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x BUSY\n",
	src_port->name(), pkt->cmdString(), pkt->getAddr());
	return false;
	}

	DPRINTF(NoncoherentXBar, "recvTimingResp: src %s %s 0x%x\n",
	src_port->name(), pkt->cmdString(), pkt->getAddr());

	// store size and command as they might be modified when
	// forwarding the packet
	unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
	unsigned int pkt_cmd = pkt->cmdToIndex();

	// a response sees the response latency
	Tick xbar_delay = responseLatency * clockPeriod();

	// set the packet header and payload delay
	calcPacketTiming(pkt, xbar_delay);

	// determine how long to be crossbar layer is busy
	Tick packetFinishTime = clockEdge(Cycles(1)) + pkt->payloadDelay;

	// send the packet through the destination CPU-side port, and pay for
	// any outstanding latency
	Tick latency = pkt->headerDelay;
	pkt->headerDelay = 0;
	cpuSidePorts[cpu_side_port_id]->schedTimingResp(pkt,
	curTick() + latency);

	// remove the request from the routing table
	routeTo.erase(route_lookup);

	respLayers[cpu_side_port_id]->succeededTiming(packetFinishTime);

	// stats updates
	pktCount[cpu_side_port_id][mem_side_port_id]++;
	pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
	transDist[pkt_cmd]++;

	return true;
	}

	void
	NoncoherentXBar::recvReqRetry(PortID mem_side_port_id)
	{
	// responses never block on forwarding them, so the retry will
	// always be coming from a port to which we tried to forward a
	// request
	reqLayers[mem_side_port_id]->recvRetry();
	}

	Tick
	NoncoherentXBar::recvAtomicBackdoor(PacketPtr pkt, PortID cpu_side_port_id,
	MemBackdoorPtr *backdoor)
	{
	DPRINTF(NoncoherentXBar, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
	cpuSidePorts[cpu_side_port_id]->name(), pkt->getAddr(),
	pkt->cmdString());

	unsigned int pkt_size = pkt->hasData() ? pkt->getSize() : 0;
	unsigned int pkt_cmd = pkt->cmdToIndex();

	// determine the destination port
	PortID mem_side_port_id = findPort(pkt->getAddrRange());

	// stats updates for the request
	pktCount[cpu_side_port_id][mem_side_port_id]++;
	pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
	transDist[pkt_cmd]++;

	// forward the request to the appropriate destination
	auto mem_side_port = memSidePorts[mem_side_port_id];
	Tick response_latency = backdoor ?
	mem_side_port->sendAtomicBackdoor(pkt, *backdoor) :
	mem_side_port->sendAtomic(pkt);

	// add the response data
	if (pkt->isResponse()) {
	pkt_size = pkt->hasData() ? pkt->getSize() : 0;
	pkt_cmd = pkt->cmdToIndex();

	// stats updates
	pktCount[cpu_side_port_id][mem_side_port_id]++;
	pktSize[cpu_side_port_id][mem_side_port_id] += pkt_size;
	transDist[pkt_cmd]++;
	}

	// @todo: Not setting first-word time
	pkt->payloadDelay = response_latency;
	return response_latency;
	}

	void
	NoncoherentXBar::recvMemBackdoorReq(const MemBackdoorReq &req,
	MemBackdoorPtr &backdoor)
	{
	PortID dest_id = findPort(req.range());
	memSidePorts[dest_id]->sendMemBackdoorReq(req, backdoor);
	}

	void
	NoncoherentXBar::recvFunctional(PacketPtr pkt, PortID cpu_side_port_id)
	{
	if (!pkt->isPrint()) {
	// don't do DPRINTFs on PrintReq as it clutters up the output
	DPRINTF(NoncoherentXBar,
	"recvFunctional: packet src %s addr 0x%x cmd %s\n",
	cpuSidePorts[cpu_side_port_id]->name(), pkt->getAddr(),
	pkt->cmdString());
	}

	// since our CPU-side ports are queued ports we need to check them as well
	for (const auto& p : cpuSidePorts) {
	// if we find a response that has the data, then the
	// downstream caches/memories may be out of date, so simply stop
	// here
	if (p->trySatisfyFunctional(pkt)) {
	if (pkt->needsResponse())
	pkt->makeResponse();
	return;
	}
	}

	// determine the destination port
	PortID dest_id = findPort(pkt->getAddrRange());

	// forward the request to the appropriate destination
	memSidePorts[dest_id]->sendFunctional(pkt);
	}

	} // namespace gem5