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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 AddrRange addr_range
= RangeSize(pkt
->getAddr(), pkt
->getSize());
112 PortID master_port_id
= findPort(addr_range
);
114 // test if the layer should be considered occupied for the current
116 if (!reqLayers
[master_port_id
]->tryTiming(src_port
)) {
117 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x BUSY\n",
118 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
122 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x\n",
123 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
125 // store size and command as they might be modified when
126 // forwarding the packet
127 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
128 unsigned int pkt_cmd
= pkt
->cmdToIndex();
130 // store the old header delay so we can restore it if needed
131 Tick old_header_delay
= pkt
->headerDelay
;
133 // a request sees the frontend and forward latency
134 Tick xbar_delay
= (frontendLatency
+ forwardLatency
) * clockPeriod();
136 // set the packet header and payload delay
137 calcPacketTiming(pkt
, xbar_delay
);
139 // determine how long to be crossbar layer is busy
140 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
142 // before forwarding the packet (and possibly altering it),
143 // remember if we are expecting a response
144 const bool expect_response
= pkt
->needsResponse() &&
145 !pkt
->cacheResponding();
147 // since it is a normal request, attempt to send the packet
148 bool success
= masterPorts
[master_port_id
]->sendTimingReq(pkt
);
151 DPRINTF(NoncoherentXBar
, "recvTimingReq: src %s %s 0x%x RETRY\n",
152 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
154 // restore the header delay as it is additive
155 pkt
->headerDelay
= old_header_delay
;
157 // occupy until the header is sent
158 reqLayers
[master_port_id
]->failedTiming(src_port
,
159 clockEdge(Cycles(1)));
164 // remember where to route the response to
165 if (expect_response
) {
166 assert(routeTo
.find(pkt
->req
) == routeTo
.end());
167 routeTo
[pkt
->req
] = slave_port_id
;
170 reqLayers
[master_port_id
]->succeededTiming(packetFinishTime
);
173 pktCount
[slave_port_id
][master_port_id
]++;
174 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
175 transDist
[pkt_cmd
]++;
181 NoncoherentXBar::recvTimingResp(PacketPtr pkt
, PortID master_port_id
)
183 // determine the source port based on the id
184 MasterPort
*src_port
= masterPorts
[master_port_id
];
186 // determine the destination
187 const auto route_lookup
= routeTo
.find(pkt
->req
);
188 assert(route_lookup
!= routeTo
.end());
189 const PortID slave_port_id
= route_lookup
->second
;
190 assert(slave_port_id
!= InvalidPortID
);
191 assert(slave_port_id
< respLayers
.size());
193 // test if the layer should be considered occupied for the current
195 if (!respLayers
[slave_port_id
]->tryTiming(src_port
)) {
196 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x BUSY\n",
197 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
201 DPRINTF(NoncoherentXBar
, "recvTimingResp: src %s %s 0x%x\n",
202 src_port
->name(), pkt
->cmdString(), pkt
->getAddr());
204 // store size and command as they might be modified when
205 // forwarding the packet
206 unsigned int pkt_size
= pkt
->hasData() ? pkt
->getSize() : 0;
207 unsigned int pkt_cmd
= pkt
->cmdToIndex();
209 // a response sees the response latency
210 Tick xbar_delay
= responseLatency
* clockPeriod();
212 // set the packet header and payload delay
213 calcPacketTiming(pkt
, xbar_delay
);
215 // determine how long to be crossbar layer is busy
216 Tick packetFinishTime
= clockEdge(Cycles(1)) + pkt
->payloadDelay
;
218 // send the packet through the destination slave port, and pay for
219 // any outstanding latency
220 Tick latency
= pkt
->headerDelay
;
221 pkt
->headerDelay
= 0;
222 slavePorts
[slave_port_id
]->schedTimingResp(pkt
, curTick() + latency
);
224 // remove the request from the routing table
225 routeTo
.erase(route_lookup
);
227 respLayers
[slave_port_id
]->succeededTiming(packetFinishTime
);
230 pktCount
[slave_port_id
][master_port_id
]++;
231 pktSize
[slave_port_id
][master_port_id
] += pkt_size
;
232 transDist
[pkt_cmd
]++;
238 NoncoherentXBar::recvReqRetry(PortID master_port_id
)
240 // responses never block on forwarding them, so the retry will
241 // always be coming from a port to which we tried to forward a
243 reqLayers
[master_port_id
]->recvRetry();
247 NoncoherentXBar::recvAtomic(PacketPtr pkt
, PortID slave_port_id
)
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 AddrRange addr_range
= RangeSize(pkt
->getAddr(), pkt
->getSize());
258 PortID master_port_id
= findPort(addr_range
);
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 AddrRange addr_range
= RangeSize(pkt
->getAddr(), pkt
->getSize());
309 PortID dest_id
= findPort(addr_range
);
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
)