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47 * Definition of a non-coherent crossbar object.
50 #include "mem/noncoherent_xbar.hh"
52 #include "base/logging.hh"
53 #include "base/trace.hh"
54 #include "debug/NoncoherentXBar.hh"
55 #include "debug/XBar.hh"
57 NoncoherentXBar::NoncoherentXBar(const NoncoherentXBarParams
*p
)
60 // create the ports based on the size of the master and slave
61 // vector ports, and the presence of the default port, the ports
62 // are enumerated starting from zero
63 for (int i
= 0; i
< p
->port_master_connection_count
; ++i
) {
64 std::string portName
= csprintf("%s.master[%d]", name(), i
);
65 MasterPort
* bp
= new NoncoherentXBarMasterPort(portName
, *this, i
);
66 masterPorts
.push_back(bp
);
67 reqLayers
.push_back(new ReqLayer(*bp
, *this,
68 csprintf(".reqLayer%d", i
)));
71 // see if we have a default slave device connected and if so add
72 // our corresponding master port
73 if (p
->port_default_connection_count
) {
74 defaultPortID
= masterPorts
.size();
75 std::string portName
= name() + ".default";
76 MasterPort
* bp
= new NoncoherentXBarMasterPort(portName
, *this,
78 masterPorts
.push_back(bp
);
79 reqLayers
.push_back(new ReqLayer(*bp
, *this, csprintf(".reqLayer%d",
83 // create the slave ports, once again starting at zero
84 for (int i
= 0; i
< p
->port_slave_connection_count
; ++i
) {
85 std::string portName
= csprintf("%s.slave[%d]", name(), i
);
86 QueuedSlavePort
* bp
= new NoncoherentXBarSlavePort(portName
, *this, i
);
87 slavePorts
.push_back(bp
);
88 respLayers
.push_back(new RespLayer(*bp
, *this,
89 csprintf(".respLayer%d", i
)));
93 NoncoherentXBar::~NoncoherentXBar()
95 for (auto l
: reqLayers
)
97 for (auto l
: respLayers
)
102 NoncoherentXBar::recvTimingReq(PacketPtr pkt
, PortID slave_port_id
)
104 // determine the source port based on the id
105 SlavePort
*src_port
= slavePorts
[slave_port_id
];
107 // we should never see express snoops on a non-coherent crossbar
108 assert(!pkt
->isExpressSnoop());
110 // determine the destination based on the address
111 PortID master_port_id
= findPort(pkt
->getAddrRange());
113 // test if the layer should be considered occupied for the current
115 if (!reqLayers
[master_port_id
]->tryTiming(src_port
)) {
116 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x BUSY\n",
117 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
121 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x\n",
122 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
124 // store size and command as they might be modified when
125 // forwarding the packet
126 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
127 unsigned int pkt_cmd
= pkt
->cmdToIndex();
129 // store the old header delay so we can restore it if needed
130 Tick old_header_delay
= pkt
->headerDelay
;
132 // a request sees the frontend and forward latency
133 Tick xbar_delay
= (frontendLatency
+ forwardLatency
) * clockPeriod();
135 // set the packet header and payload delay
136 calcPacketTiming(pkt
, xbar_delay
);
138 // determine how long to be crossbar layer is busy
139 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
141 // before forwarding the packet (and possibly altering it),
142 // remember if we are expecting a response
143 const bool expect_response
= pkt
->needsResponse() &&
144 !pkt
->cacheResponding();
146 // since it is a normal request, attempt to send the packet
147 bool success
= masterPorts
[master_port_id
]->sendTimingReq(pkt
);
150 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x RETRY\n",
151 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
153 // restore the header delay as it is additive
154 pkt
->headerDelay
= old_header_delay
;
156 // occupy until the header is sent
157 reqLayers
[master_port_id
]->failedTiming(src_port
,
158 clockEdge(Cycles(1)));
163 // remember where to route the response to
164 if (expect_response
) {
165 assert(routeTo
.find(pkt
->req
) == routeTo
.end());
166 routeTo
[pkt
->req
] = slave_port_id
;
169 reqLayers
[master_port_id
]->succeededTiming(packetFinishTime
);
172 pktCount
[slave_port_id
][master_port_id
]++;
173 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
174 transDist
[pkt_cmd
]++;
180 NoncoherentXBar::recvTimingResp(PacketPtr pkt
, PortID master_port_id
)
182 // determine the source port based on the id
183 MasterPort
*src_port
= masterPorts
[master_port_id
];
185 // determine the destination
186 const auto route_lookup
= routeTo
.find(pkt
->req
);
187 assert(route_lookup
!= routeTo
.end());
188 const PortID slave_port_id
= route_lookup
->second
;
189 assert(slave_port_id
!= InvalidPortID
);
190 assert(slave_port_id
< respLayers
.size());
192 // test if the layer should be considered occupied for the current
194 if (!respLayers
[slave_port_id
]->tryTiming(src_port
)) {
195 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x BUSY\n",
196 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
200 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x\n",
201 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
203 // store size and command as they might be modified when
204 // forwarding the packet
205 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
206 unsigned int pkt_cmd
= pkt
->cmdToIndex();
208 // a response sees the response latency
209 Tick xbar_delay
= responseLatency
* clockPeriod();
211 // set the packet header and payload delay
212 calcPacketTiming(pkt
, xbar_delay
);
214 // determine how long to be crossbar layer is busy
215 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
217 // send the packet through the destination slave port, and pay for
218 // any outstanding latency
219 Tick latency
= pkt
->headerDelay
;
220 pkt
->headerDelay
= 0;
221 slavePorts
[slave_port_id
]->schedTimingResp(pkt
, curTick() + latency
);
223 // remove the request from the routing table
224 routeTo
.erase(route_lookup
);
226 respLayers
[slave_port_id
]->succeededTiming(packetFinishTime
);
229 pktCount
[slave_port_id
][master_port_id
]++;
230 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
231 transDist
[pkt_cmd
]++;
237 NoncoherentXBar::recvReqRetry(PortID master_port_id
)
239 // responses never block on forwarding them, so the retry will
240 // always be coming from a port to which we tried to forward a
242 reqLayers
[master_port_id
]->recvRetry();
246 NoncoherentXBar::recvAtomicBackdoor(PacketPtr pkt
, PortID slave_port_id
,
247 MemBackdoorPtr
*backdoor
)
249 DPRINTF(NoncoherentXBar
, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
250 slavePorts
[slave_port_id
]->name(), pkt
->getAddr(),
253 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
254 unsigned int pkt_cmd
= pkt
->cmdToIndex();
256 // determine the destination port
257 PortID master_port_id
= findPort(pkt
->getAddrRange());
259 // stats updates for the request
260 pktCount
[slave_port_id
][master_port_id
]++;
261 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
262 transDist
[pkt_cmd
]++;
264 // forward the request to the appropriate destination
265 auto master
= masterPorts
[master_port_id
];
266 Tick response_latency
= backdoor
?
267 master
->sendAtomicBackdoor(pkt
, *backdoor
) : master
->sendAtomic(pkt
);
269 // add the response data
270 if (pkt
->isResponse()) {
271 pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
272 pkt_cmd
= pkt
->cmdToIndex();
275 pktCount
[slave_port_id
][master_port_id
]++;
276 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
277 transDist
[pkt_cmd
]++;
280 // @todo: Not setting first-word time
281 pkt
->payloadDelay
= response_latency
;
282 return response_latency
;
286 NoncoherentXBar::recvFunctional(PacketPtr pkt
, PortID slave_port_id
)
288 if (!pkt
->isPrint()) {
289 // don't do DPRINTFs on PrintReq as it clutters up the output
290 DPRINTF(NoncoherentXBar
,
291 "recvFunctional: packet src %s addr 0x%x cmd %s\n",
292 slavePorts
[slave_port_id
]->name(), pkt
->getAddr(),
296 // since our slave ports are queued ports we need to check them as well
297 for (const auto& p
: slavePorts
) {
298 // if we find a response that has the data, then the
299 // downstream caches/memories may be out of date, so simply stop
301 if (p
->trySatisfyFunctional(pkt
)) {
302 if (pkt
->needsResponse())
308 // determine the destination port
309 PortID dest_id
= findPort(pkt
->getAddrRange());
311 // forward the request to the appropriate destination
312 masterPorts
[dest_id
]->sendFunctional(pkt
);
316 NoncoherentXBarParams::create()
318 return new NoncoherentXBar(this);
322 NoncoherentXBar::regStats()
324 // register the stats of the base class and our layers
325 BaseXBar::regStats();
326 for (auto l
: reqLayers
)
328 for (auto l
: respLayers
)