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40 * Authors: Erik Hallnor
45 * Declaration of a structure to manage MSHRs.
48 #ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__
49 #define __MEM__CACHE__MISS__MSHR_QUEUE_HH__
53 #include "mem/cache/mshr.hh"
54 #include "mem/packet.hh"
55 #include "sim/drain.hh"
58 * A Class for maintaining a list of pending and allocated memory requests.
60 class MSHRQueue : public Drainable
63 /** Local label (for functional print requests) */
64 const std::string label;
68 /** Holds pointers to all allocated entries. */
69 MSHR::List allocatedList;
70 /** Holds pointers to entries that haven't been sent to the bus. */
72 /** Holds non allocated entries. */
77 * The total number of entries in this queue. This number is set as the
78 * number of entries requested plus (numReserve - 1). This allows for
79 * the same number of effective entries while still maintaining the reserve.
84 * The number of entries to hold in reserve. This is needed because copy
85 * operations can allocate upto 4 entries at one time.
89 /** Drain manager to inform of a completed drain */
90 DrainManager *drainManager;
92 MSHR::Iterator addToReadyList(MSHR *mshr);
96 /** The number of allocated entries. */
98 /** The number of entries that have been forwarded to the bus. */
100 /** The index of this queue within the cache (MSHR queue vs. write
105 * Create a queue with a given number of entries.
106 * @param num_entrys The number of entries in this queue.
107 * @param reserve The minimum number of entries needed to satisfy
110 MSHRQueue(const std::string &_label, int num_entries, int reserve,
117 * Find the first MSHR that matches the provided address.
118 * @param addr The address to find.
119 * @return Pointer to the matching MSHR, null if not found.
121 MSHR *findMatch(Addr addr) const;
124 * Find and return all the matching entries in the provided vector.
125 * @param addr The address to find.
126 * @param matches The vector to return pointers to the matching entries.
127 * @return True if any matches are found, false otherwise.
128 * @todo Typedef the vector??
130 bool findMatches(Addr addr, std::vector<MSHR*>& matches) const;
133 * Find any pending requests that overlap the given request.
134 * @param pkt The request to find.
135 * @return A pointer to the earliest matching MSHR.
137 MSHR *findPending(Addr addr, int size) const;
139 bool checkFunctional(PacketPtr pkt, Addr blk_addr);
142 * Allocates a new MSHR for the request and size. This places the request
143 * as the first target in the MSHR.
144 * @param pkt The request to handle.
145 * @param size The number in bytes to fetch from memory.
146 * @return The a pointer to the MSHR allocated.
148 * @pre There are free entries.
150 MSHR *allocate(Addr addr, int size, PacketPtr &pkt,
151 Tick when, Counter order);
154 * Removes the given MSHR from the queue. This places the MSHR on the
158 void deallocate(MSHR *mshr);
161 * Remove a MSHR from the queue. Returns an iterator into the
162 * allocatedList for faster squash implementation.
163 * @param mshr The MSHR to remove.
164 * @return An iterator to the next entry in the allocatedList.
166 MSHR::Iterator deallocateOne(MSHR *mshr);
169 * Moves the MSHR to the front of the pending list if it is not
171 * @param mshr The entry to move.
173 void moveToFront(MSHR *mshr);
176 * Mark the given MSHR as in service. This removes the MSHR from the
177 * readyList. Deallocates the MSHR if it does not expect a response.
178 * @param mshr The MSHR to mark in service.
180 void markInService(MSHR *mshr, PacketPtr pkt);
183 * Mark an in service entry as pending, used to resend a request.
184 * @param mshr The MSHR to resend.
186 void markPending(MSHR *mshr);
189 * Squash outstanding requests with the given thread number. If a request
190 * is in service, just squashes the targets.
191 * @param threadNum The thread to squash.
193 void squash(int threadNum);
196 * Returns true if the pending list is not empty.
197 * @return True if there are outstanding requests.
199 bool havePending() const
201 return !readyList.empty();
205 * Returns true if there are no free entries.
206 * @return True if this queue is full.
210 return (allocated > numEntries - numReserve);
214 * Returns the MSHR at the head of the readyList.
215 * @return The next request to service.
217 MSHR *getNextMSHR() const
219 if (readyList.empty() || readyList.front()->readyTime > curTick()) {
222 return readyList.front();
225 Tick nextMSHRReadyTime() const
227 return readyList.empty() ? MaxTick : readyList.front()->readyTime;
230 unsigned int drain(DrainManager *dm);
233 #endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__