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Diffstat (limited to 'src/mem/cache/mshr_queue.hh')
| -rw-r--r-- | src/mem/cache/mshr_queue.hh | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/src/mem/cache/mshr_queue.hh b/src/mem/cache/mshr_queue.hh new file mode 100644 index 000000000..f481ca471 --- /dev/null +++ b/src/mem/cache/mshr_queue.hh @@ -0,0 +1,214 @@ +/* + * Copyright (c) 2003-2005 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Erik Hallnor + */ + +/** @file + * Declaration of a structure to manage MSHRs. + */ + +#ifndef __MEM__CACHE__MISS__MSHR_QUEUE_HH__ +#define __MEM__CACHE__MISS__MSHR_QUEUE_HH__ + +#include <vector> + +#include "mem/packet.hh" +#include "mem/cache/mshr.hh" + +/** + * A Class for maintaining a list of pending and allocated memory requests. + */ +class MSHRQueue +{ + private: + /** Local label (for functional print requests) */ + const std::string label; + + /** MSHR storage. */ + MSHR *registers; + /** Holds pointers to all allocated entries. */ + MSHR::List allocatedList; + /** Holds pointers to entries that haven't been sent to the bus. */ + MSHR::List readyList; + /** Holds non allocated entries. */ + MSHR::List freeList; + + // Parameters + /** + * The total number of entries in this queue. This number is set as the + * number of entries requested plus (numReserve - 1). This allows for + * the same number of effective entries while still maintaining the reserve. + */ + const int numEntries; + + /** + * The number of entries to hold in reserve. This is needed because copy + * operations can allocate upto 4 entries at one time. + */ + const int numReserve; + + MSHR::Iterator addToReadyList(MSHR *mshr); + + + public: + /** The number of allocated entries. */ + int allocated; + /** The number of entries that have been forwarded to the bus. */ + int inServiceEntries; + /** The index of this queue within the cache (MSHR queue vs. write + * buffer). */ + const int index; + + /** + * Create a queue with a given number of entries. + * @param num_entrys The number of entries in this queue. + * @param reserve The minimum number of entries needed to satisfy + * any access. + */ + MSHRQueue(const std::string &_label, int num_entries, int reserve, + int index); + + /** Destructor */ + ~MSHRQueue(); + + /** + * Find the first MSHR that matches the provided address. + * @param addr The address to find. + * @return Pointer to the matching MSHR, null if not found. + */ + MSHR *findMatch(Addr addr) const; + + /** + * Find and return all the matching entries in the provided vector. + * @param addr The address to find. + * @param matches The vector to return pointers to the matching entries. + * @return True if any matches are found, false otherwise. + * @todo Typedef the vector?? + */ + bool findMatches(Addr addr, std::vector<MSHR*>& matches) const; + + /** + * Find any pending requests that overlap the given request. + * @param pkt The request to find. + * @return A pointer to the earliest matching MSHR. + */ + MSHR *findPending(Addr addr, int size) const; + + bool checkFunctional(PacketPtr pkt, Addr blk_addr); + + /** + * Allocates a new MSHR for the request and size. This places the request + * as the first target in the MSHR. + * @param pkt The request to handle. + * @param size The number in bytes to fetch from memory. + * @return The a pointer to the MSHR allocated. + * + * @pre There are free entries. + */ + MSHR *allocate(Addr addr, int size, PacketPtr &pkt, + Tick when, Counter order); + + /** + * Removes the given MSHR from the queue. This places the MSHR on the + * free list. + * @param mshr + */ + void deallocate(MSHR *mshr); + + /** + * Remove a MSHR from the queue. Returns an iterator into the + * allocatedList for faster squash implementation. + * @param mshr The MSHR to remove. + * @return An iterator to the next entry in the allocatedList. + */ + MSHR::Iterator deallocateOne(MSHR *mshr); + + /** + * Moves the MSHR to the front of the pending list if it is not + * in service. + * @param mshr The entry to move. + */ + void moveToFront(MSHR *mshr); + + /** + * Mark the given MSHR as in service. This removes the MSHR from the + * readyList. Deallocates the MSHR if it does not expect a response. + * @param mshr The MSHR to mark in service. + */ + void markInService(MSHR *mshr); + + /** + * Mark an in service entry as pending, used to resend a request. + * @param mshr The MSHR to resend. + */ + void markPending(MSHR *mshr); + + /** + * Squash outstanding requests with the given thread number. If a request + * is in service, just squashes the targets. + * @param threadNum The thread to squash. + */ + void squash(int threadNum); + + /** + * Returns true if the pending list is not empty. + * @return True if there are outstanding requests. + */ + bool havePending() const + { + return !readyList.empty(); + } + + /** + * Returns true if there are no free entries. + * @return True if this queue is full. + */ + bool isFull() const + { + return (allocated > numEntries - numReserve); + } + + /** + * Returns the MSHR at the head of the readyList. + * @return The next request to service. + */ + MSHR *getNextMSHR() const + { + if (readyList.empty() || readyList.front()->readyTime > curTick) { + return NULL; + } + return readyList.front(); + } + + Tick nextMSHRReadyTime() const + { + return readyList.empty() ? MaxTick : readyList.front()->readyTime; + } +}; + +#endif //__MEM__CACHE__MISS__MSHR_QUEUE_HH__ |