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44 #ifndef __MEM_PACKET_QUEUE_HH__
45 #define __MEM_PACKET_QUEUE_HH__
49 * Declaration of a simple PacketQueue that is associated with
50 * a port on which it attempts to send packets according to the time
51 * stamp given to them at insertion. The packet queue is responsible
52 * for the flow control of the port.
57 #include "mem/port.hh"
58 #include "sim/drain.hh"
59 #include "sim/eventq_impl.hh"
62 * A packet queue is a class that holds deferred packets and later
63 * sends them using the associated slave port or master port.
65 class PacketQueue : public Drainable
68 /** A deferred packet, buffered to transmit later. */
69 class DeferredPacket {
71 Tick tick; ///< The tick when the packet is ready to transmit
72 PacketPtr pkt; ///< Pointer to the packet to transmit
73 DeferredPacket(Tick t, PacketPtr p)
78 typedef std::list<DeferredPacket> DeferredPacketList;
80 /** A list of outgoing packets. */
81 DeferredPacketList transmitList;
83 /** The manager which is used for the event queue */
86 /** Used to schedule sending of deferred packets. */
87 void processSendEvent();
89 /** Event used to call processSendEvent. */
90 EventFunctionWrapper sendEvent;
93 * Optionally disable the sanity check
94 * on the size of the transmitList. The
95 * sanity check will be enabled by default.
97 bool _disableSanityCheck;
100 * if true, inserted packets have to be unconditionally scheduled
101 * after the last packet in the queue that references the same
108 /** Label to use for print request packets label stack. */
109 const std::string label;
111 /** Remember whether we're awaiting a retry. */
114 /** Check whether we have a packet ready to go on the transmit list. */
115 bool deferredPacketReady() const
116 { return !transmitList.empty() && transmitList.front().tick <= curTick(); }
119 * Attempt to send a packet. Note that a subclass of the
120 * PacketQueue can override this method and thus change the
121 * behaviour (as done by the cache for the request queue). The
122 * default implementation sends the head of the transmit list. The
123 * caller must guarantee that the list is non-empty and that the
124 * head packet is scheduled for curTick() (or earlier).
126 virtual void sendDeferredPacket();
129 * Send a packet using the appropriate method for the specific
130 * subclass (reuest, response or snoop response).
132 virtual bool sendTiming(PacketPtr pkt) = 0;
135 * Create a packet queue, linked to an event manager, and a label
136 * that will be used for functional print request packets.
138 * @param _em Event manager used for scheduling this queue
139 * @param _label Label to push on the label stack for print request packets
140 * @param force_order Force insertion order for packets with same address
141 * @param disable_sanity_check Flag used to disable the sanity check
142 * on the size of the transmitList. The check is enabled by default.
144 PacketQueue(EventManager& _em, const std::string& _label,
145 const std::string& _sendEventName,
146 bool force_order = false,
147 bool disable_sanity_check = false);
150 * Virtual desctructor since the class may be used as a base class.
152 virtual ~PacketQueue();
157 * Provide a name to simplify debugging.
159 * @return A complete name, appended to module and port
161 virtual const std::string name() const = 0;
164 * Get the size of the queue.
166 size_t size() const { return transmitList.size(); }
169 * Get the next packet ready time.
171 Tick deferredPacketReadyTime() const
172 { return transmitList.empty() ? MaxTick : transmitList.front().tick; }
175 * Check if a packet corresponding to the same address exists in the
178 * @param pkt The packet to compare against.
179 * @param blk_size Block size in bytes.
180 * @return Whether a corresponding packet is found.
182 bool checkConflict(const PacketPtr pkt, const int blk_size) const;
184 /** Check the list of buffered packets against the supplied
185 * functional request. */
186 bool trySatisfyFunctional(PacketPtr pkt);
189 * Schedule a send event if we are not already waiting for a
190 * retry. If the requested time is before an already scheduled
191 * send event, the event will be rescheduled. If MaxTick is
192 * passed, no event is scheduled. Instead, if we are idle and
193 * asked to drain then check and signal drained.
195 * @param when time to schedule an event
197 void schedSendEvent(Tick when);
200 * Add a packet to the transmit list, and schedule a send event.
202 * @param pkt Packet to send
203 * @param when Absolute time (in ticks) to send packet
205 void schedSendTiming(PacketPtr pkt, Tick when);
208 * Retry sending a packet from the queue. Note that this is not
209 * necessarily the same packet if something has been added with an
210 * earlier time stamp.
215 * This allows a user to explicitly disable the sanity check
216 * on the size of the transmitList, which is enabled by default.
217 * Users must use this function to explicitly disable the sanity
220 void disableSanityCheck() { _disableSanityCheck = true; }
222 DrainState drain() override;
225 class ReqPacketQueue : public PacketQueue
230 MasterPort& masterPort;
232 // Static definition so it can be called when constructing the parent
233 // without us being completely initialized.
234 static const std::string name(const MasterPort& masterPort,
235 const std::string& label)
236 { return masterPort.name() + "-" + label; }
241 * Create a request packet queue, linked to an event manager, a
242 * master port, and a label that will be used for functional print
245 * @param _em Event manager used for scheduling this queue
246 * @param _masterPort Master port used to send the packets
247 * @param _label Label to push on the label stack for print request packets
249 ReqPacketQueue(EventManager& _em, MasterPort& _masterPort,
250 const std::string _label = "ReqPacketQueue");
252 virtual ~ReqPacketQueue() { }
254 const std::string name() const
255 { return name(masterPort, label); }
257 bool sendTiming(PacketPtr pkt);
261 class SnoopRespPacketQueue : public PacketQueue
266 MasterPort& masterPort;
268 // Static definition so it can be called when constructing the parent
269 // without us being completely initialized.
270 static const std::string name(const MasterPort& masterPort,
271 const std::string& label)
272 { return masterPort.name() + "-" + label; }
277 * Create a snoop response packet queue, linked to an event
278 * manager, a master port, and a label that will be used for
279 * functional print request packets.
281 * @param _em Event manager used for scheduling this queue
282 * @param _masterPort Master port used to send the packets
283 * @param force_order Force insertion order for packets with same address
284 * @param _label Label to push on the label stack for print request packets
286 SnoopRespPacketQueue(EventManager& _em, MasterPort& _masterPort,
287 bool force_order = false,
288 const std::string _label = "SnoopRespPacketQueue");
290 virtual ~SnoopRespPacketQueue() { }
292 const std::string name() const
293 { return name(masterPort, label); }
295 bool sendTiming(PacketPtr pkt);
299 class RespPacketQueue : public PacketQueue
304 SlavePort& slavePort;
306 // Static definition so it can be called when constructing the parent
307 // without us being completely initialized.
308 static const std::string name(const SlavePort& slavePort,
309 const std::string& label)
310 { return slavePort.name() + "-" + label; }
315 * Create a response packet queue, linked to an event manager, a
316 * slave port, and a label that will be used for functional print
319 * @param _em Event manager used for scheduling this queue
320 * @param _slavePort Slave port used to send the packets
321 * @param force_order Force insertion order for packets with same address
322 * @param _label Label to push on the label stack for print request packets
324 RespPacketQueue(EventManager& _em, SlavePort& _slavePort,
325 bool force_order = false,
326 const std::string _label = "RespPacketQueue");
328 virtual ~RespPacketQueue() { }
330 const std::string name() const
331 { return name(slavePort, label); }
333 bool sendTiming(PacketPtr pkt);
337 #endif // __MEM_PACKET_QUEUE_HH__