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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
)));
95 NoncoherentXBar::~NoncoherentXBar()
97 for (auto l
: reqLayers
)
99 for (auto l
: respLayers
)
104 NoncoherentXBar::recvTimingReq(PacketPtr pkt
, PortID slave_port_id
)
106 // determine the source port based on the id
107 SlavePort
*src_port
= slavePorts
[slave_port_id
];
109 // we should never see express snoops on a non-coherent crossbar
110 assert(!pkt
->isExpressSnoop());
112 // determine the destination based on the address
113 PortID master_port_id
= findPort(pkt
->getAddr());
115 // test if the layer should be considered occupied for the current
117 if (!reqLayers
[master_port_id
]->tryTiming(src_port
)) {
118 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x BUSY\n",
119 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
123 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x\n",
124 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
126 // store size and command as they might be modified when
127 // forwarding the packet
128 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
129 unsigned int pkt_cmd
= pkt
->cmdToIndex();
131 // store the old header delay so we can restore it if needed
132 Tick old_header_delay
= pkt
->headerDelay
;
134 // a request sees the frontend and forward latency
135 Tick xbar_delay
= (frontendLatency
+ forwardLatency
) * clockPeriod();
137 // set the packet header and payload delay
138 calcPacketTiming(pkt
, xbar_delay
);
140 // determine how long to be crossbar layer is busy
141 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
143 // before forwarding the packet (and possibly altering it),
144 // remember if we are expecting a response
145 const bool expect_response
= pkt
->needsResponse() &&
146 !pkt
->cacheResponding();
148 // since it is a normal request, attempt to send the packet
149 bool success
= masterPorts
[master_port_id
]->sendTimingReq(pkt
);
152 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x RETRY\n",
153 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
155 // restore the header delay as it is additive
156 pkt
->headerDelay
= old_header_delay
;
158 // occupy until the header is sent
159 reqLayers
[master_port_id
]->failedTiming(src_port
,
160 clockEdge(Cycles(1)));
165 // remember where to route the response to
166 if (expect_response
) {
167 assert(routeTo
.find(pkt
->req
) == routeTo
.end());
168 routeTo
[pkt
->req
] = slave_port_id
;
171 reqLayers
[master_port_id
]->succeededTiming(packetFinishTime
);
174 pktCount
[slave_port_id
][master_port_id
]++;
175 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
176 transDist
[pkt_cmd
]++;
182 NoncoherentXBar::recvTimingResp(PacketPtr pkt
, PortID master_port_id
)
184 // determine the source port based on the id
185 MasterPort
*src_port
= masterPorts
[master_port_id
];
187 // determine the destination
188 const auto route_lookup
= routeTo
.find(pkt
->req
);
189 assert(route_lookup
!= routeTo
.end());
190 const PortID slave_port_id
= route_lookup
->second
;
191 assert(slave_port_id
!= InvalidPortID
);
192 assert(slave_port_id
< respLayers
.size());
194 // test if the layer should be considered occupied for the current
196 if (!respLayers
[slave_port_id
]->tryTiming(src_port
)) {
197 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x BUSY\n",
198 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
202 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x\n",
203 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
205 // store size and command as they might be modified when
206 // forwarding the packet
207 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
208 unsigned int pkt_cmd
= pkt
->cmdToIndex();
210 // a response sees the response latency
211 Tick xbar_delay
= responseLatency
* clockPeriod();
213 // set the packet header and payload delay
214 calcPacketTiming(pkt
, xbar_delay
);
216 // determine how long to be crossbar layer is busy
217 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
219 // send the packet through the destination slave port, and pay for
220 // any outstanding latency
221 Tick latency
= pkt
->headerDelay
;
222 pkt
->headerDelay
= 0;
223 slavePorts
[slave_port_id
]->schedTimingResp(pkt
, curTick() + latency
);
225 // remove the request from the routing table
226 routeTo
.erase(route_lookup
);
228 respLayers
[slave_port_id
]->succeededTiming(packetFinishTime
);
231 pktCount
[slave_port_id
][master_port_id
]++;
232 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
233 transDist
[pkt_cmd
]++;
239 NoncoherentXBar::recvReqRetry(PortID master_port_id
)
241 // responses never block on forwarding them, so the retry will
242 // always be coming from a port to which we tried to forward a
244 reqLayers
[master_port_id
]->recvRetry();
248 NoncoherentXBar::recvAtomic(PacketPtr pkt
, PortID slave_port_id
)
250 DPRINTF(NoncoherentXBar
, "recvAtomic: packet src %s addr 0x%x cmd %s\n",
251 slavePorts
[slave_port_id
]->name(), pkt
->getAddr(),
254 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
255 unsigned int pkt_cmd
= pkt
->cmdToIndex();
257 // determine the destination port
258 PortID master_port_id
= findPort(pkt
->getAddr());
260 // stats updates for the request
261 pktCount
[slave_port_id
][master_port_id
]++;
262 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
263 transDist
[pkt_cmd
]++;
265 // forward the request to the appropriate destination
266 Tick response_latency
= masterPorts
[master_port_id
]->sendAtomic(pkt
);
268 // add the response data
269 if (pkt
->isResponse()) {
270 pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
271 pkt_cmd
= pkt
->cmdToIndex();
274 pktCount
[slave_port_id
][master_port_id
]++;
275 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
276 transDist
[pkt_cmd
]++;
279 // @todo: Not setting first-word time
280 pkt
->payloadDelay
= response_latency
;
281 return response_latency
;
285 NoncoherentXBar::recvFunctional(PacketPtr pkt
, PortID slave_port_id
)
287 if (!pkt
->isPrint()) {
288 // don't do DPRINTFs on PrintReq as it clutters up the output
289 DPRINTF(NoncoherentXBar
,
290 "recvFunctional: packet src %s addr 0x%x cmd %s\n",
291 slavePorts
[slave_port_id
]->name(), pkt
->getAddr(),
295 // since our slave ports are queued ports we need to check them as well
296 for (const auto& p
: slavePorts
) {
297 // if we find a response that has the data, then the
298 // downstream caches/memories may be out of date, so simply stop
300 if (p
->checkFunctional(pkt
)) {
301 if (pkt
->needsResponse())
307 // determine the destination port
308 PortID dest_id
= findPort(pkt
->getAddr());
310 // forward the request to the appropriate destination
311 masterPorts
[dest_id
]->sendFunctional(pkt
);
315 NoncoherentXBarParams::create()
317 return new NoncoherentXBar(this);
321 NoncoherentXBar::regStats()
323 // register the stats of the base class and our layers
324 BaseXBar::regStats();
325 for (auto l
: reqLayers
)
327 for (auto l
: respLayers
)