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Diffstat (limited to 'src/mem/cache/miss/miss_queue.hh')
| -rw-r--r-- | src/mem/cache/miss/miss_queue.hh | 349 |
1 files changed, 349 insertions, 0 deletions
diff --git a/src/mem/cache/miss/miss_queue.hh b/src/mem/cache/miss/miss_queue.hh new file mode 100644 index 000000000..ce827fe81 --- /dev/null +++ b/src/mem/cache/miss/miss_queue.hh @@ -0,0 +1,349 @@ +/* + * 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 + * Miss and writeback queue declarations. + */ + +#ifndef __MISS_QUEUE_HH__ +#define __MISS_QUEUE_HH__ + +#include <vector> + +#include "mem/cache/miss/mshr.hh" +#include "mem/cache/miss/mshr_queue.hh" +#include "base/statistics.hh" + +class BaseCache; +class BasePrefetcher; +/** + * Manages cache misses and writebacks. Contains MSHRs to store miss data + * and the writebuffer for writes/writebacks. + * @todo need to handle data on writes better (encapsulate). + * @todo need to make replacements/writebacks happen in Cache::access + */ +class MissQueue +{ + protected: + /** The MSHRs. */ + MSHRQueue mq; + /** Write Buffer. */ + MSHRQueue wb; + + // PARAMTERS + + /** The number of MSHRs in the miss queue. */ + const int numMSHR; + /** The number of targets for each MSHR. */ + const int numTarget; + /** The number of write buffers. */ + const int writeBuffers; + /** True if the cache should allocate on a write miss. */ + const bool writeAllocate; + /** Pointer to the parent cache. */ + BaseCache* cache; + + /** The Prefetcher */ + BasePrefetcher *prefetcher; + + /** The block size of the parent cache. */ + int blkSize; + + /** Increasing order number assigned to each incoming request. */ + uint64_t order; + + bool prefetchMiss; + + // Statistics + /** + * @addtogroup CacheStatistics + * @{ + */ + /** Number of blocks written back per thread. */ + Stats::Vector<> writebacks; + + /** Number of misses that hit in the MSHRs per command and thread. */ + Stats::Vector<> mshr_hits[NUM_MEM_CMDS]; + /** Demand misses that hit in the MSHRs. */ + Stats::Formula demandMshrHits; + /** Total number of misses that hit in the MSHRs. */ + Stats::Formula overallMshrHits; + + /** Number of misses that miss in the MSHRs, per command and thread. */ + Stats::Vector<> mshr_misses[NUM_MEM_CMDS]; + /** Demand misses that miss in the MSHRs. */ + Stats::Formula demandMshrMisses; + /** Total number of misses that miss in the MSHRs. */ + Stats::Formula overallMshrMisses; + + /** Number of misses that miss in the MSHRs, per command and thread. */ + Stats::Vector<> mshr_uncacheable[NUM_MEM_CMDS]; + /** Total number of misses that miss in the MSHRs. */ + Stats::Formula overallMshrUncacheable; + + /** Total cycle latency of each MSHR miss, per command and thread. */ + Stats::Vector<> mshr_miss_latency[NUM_MEM_CMDS]; + /** Total cycle latency of demand MSHR misses. */ + Stats::Formula demandMshrMissLatency; + /** Total cycle latency of overall MSHR misses. */ + Stats::Formula overallMshrMissLatency; + + /** Total cycle latency of each MSHR miss, per command and thread. */ + Stats::Vector<> mshr_uncacheable_lat[NUM_MEM_CMDS]; + /** Total cycle latency of overall MSHR misses. */ + Stats::Formula overallMshrUncacheableLatency; + + /** The total number of MSHR accesses per command and thread. */ + Stats::Formula mshrAccesses[NUM_MEM_CMDS]; + /** The total number of demand MSHR accesses. */ + Stats::Formula demandMshrAccesses; + /** The total number of MSHR accesses. */ + Stats::Formula overallMshrAccesses; + + /** The miss rate in the MSHRs pre command and thread. */ + Stats::Formula mshrMissRate[NUM_MEM_CMDS]; + /** The demand miss rate in the MSHRs. */ + Stats::Formula demandMshrMissRate; + /** The overall miss rate in the MSHRs. */ + Stats::Formula overallMshrMissRate; + + /** The average latency of an MSHR miss, per command and thread. */ + Stats::Formula avgMshrMissLatency[NUM_MEM_CMDS]; + /** The average latency of a demand MSHR miss. */ + Stats::Formula demandAvgMshrMissLatency; + /** The average overall latency of an MSHR miss. */ + Stats::Formula overallAvgMshrMissLatency; + + /** The average latency of an MSHR miss, per command and thread. */ + Stats::Formula avgMshrUncacheableLatency[NUM_MEM_CMDS]; + /** The average overall latency of an MSHR miss. */ + Stats::Formula overallAvgMshrUncacheableLatency; + + /** The number of times a thread hit its MSHR cap. */ + Stats::Vector<> mshr_cap_events; + /** The number of times software prefetches caused the MSHR to block. */ + Stats::Vector<> soft_prefetch_mshr_full; + + Stats::Scalar<> mshr_no_allocate_misses; + + /** + * @} + */ + + private: + /** Pointer to the MSHR that has no targets. */ + MSHR* noTargetMSHR; + + /** + * Allocate a new MSHR to handle the provided miss. + * @param req The miss to buffer. + * @param size The number of bytes to fetch. + * @param time The time the miss occurs. + * @return A pointer to the new MSHR. + */ + MSHR* allocateMiss(Packet * &pkt, int size, Tick time); + + /** + * Allocate a new WriteBuffer to handle the provided write. + * @param req The write to handle. + * @param size The number of bytes to write. + * @param time The time the write occurs. + * @return A pointer to the new write buffer. + */ + MSHR* allocateWrite(Packet * &pkt, int size, Tick time); + + public: + /** + * Simple Constructor. Initializes all needed internal storage and sets + * parameters. + * @param numMSHRs The number of outstanding misses to handle. + * @param numTargets The number of outstanding targets to each miss. + * @param write_buffers The number of outstanding writes to handle. + * @param write_allocate If true, treat write misses the same as reads. + */ + MissQueue(int numMSHRs, int numTargets, int write_buffers, + bool write_allocate, bool prefetch_miss); + + /** + * Deletes all allocated internal storage. + */ + ~MissQueue(); + + /** + * Register statistics for this object. + * @param name The name of the parent cache. + */ + void regStats(const std::string &name); + + /** + * Called by the parent cache to set the back pointer. + * @param _cache A pointer to the parent cache. + */ + void setCache(BaseCache *_cache); + + void setPrefetcher(BasePrefetcher *_prefetcher); + + /** + * Handle a cache miss properly. Either allocate an MSHR for the request, + * or forward it through the write buffer. + * @param req The request that missed in the cache. + * @param blk_size The block size of the cache. + * @param time The time the miss is detected. + */ + void handleMiss(Packet * &pkt, int blk_size, Tick time); + + /** + * Fetch the block for the given address and buffer the given target. + * @param addr The address to fetch. + * @param asid The address space of the address. + * @param blk_size The block size of the cache. + * @param time The time the miss is detected. + * @param target The target for the fetch. + */ + MSHR* fetchBlock(Addr addr, int asid, int blk_size, Tick time, + Packet * &target); + + /** + * Selects a outstanding request to service. + * @return The request to service, NULL if none found. + */ + Packet * getPacket(); + + /** + * Set the command to the given bus command. + * @param req The request to update. + * @param cmd The bus command to use. + */ + void setBusCmd(Packet * &pkt, Packet::Command cmd); + + /** + * Restore the original command in case of a bus transmission error. + * @param req The request to reset. + */ + void restoreOrigCmd(Packet * &pkt); + + /** + * Marks a request as in service (sent on the bus). This can have side + * effect since storage for no response commands is deallocated once they + * are successfully sent. + * @param req The request that was sent on the bus. + */ + void markInService(Packet * &pkt); + + /** + * Collect statistics and free resources of a satisfied request. + * @param req The request that has been satisfied. + * @param time The time when the request is satisfied. + */ + void handleResponse(Packet * &pkt, Tick time); + + /** + * Removes all outstanding requests for a given thread number. If a request + * has been sent to the bus, this function removes all of its targets. + * @param thread_number The thread number of the requests to squash. + */ + void squash(int thread_number); + + /** + * Return the current number of outstanding misses. + * @return the number of outstanding misses. + */ + int getMisses() + { + return mq.getAllocatedTargets(); + } + + /** + * Searches for the supplied address in the miss queue. + * @param addr The address to look for. + * @param asid The address space id. + * @return The MSHR that contains the address, NULL if not found. + * @warning Currently only searches the miss queue. If non write allocate + * might need to search the write buffer for coherence. + */ + MSHR* findMSHR(Addr addr, int asid) const; + + /** + * Searches for the supplied address in the write buffer. + * @param addr The address to look for. + * @param asid The address space id. + * @param writes The list of writes that match the address. + * @return True if any writes are found + */ + bool findWrites(Addr addr, int asid, std::vector<MSHR*>& writes) const; + + /** + * Perform a writeback of dirty data to the given address. + * @param addr The address to write to. + * @param asid The address space id. + * @param xc The execution context of the address space. + * @param size The number of bytes to write. + * @param data The data to write, can be NULL. + * @param compressed True if the data is compressed. + */ + void doWriteback(Addr addr, int asid, + int size, uint8_t *data, bool compressed); + + /** + * Perform the given writeback request. + * @param req The writeback request. + */ + void doWriteback(Packet * &pkt); + + /** + * Returns true if there are outstanding requests. + * @return True if there are outstanding requests. + */ + bool havePending(); + + /** + * Add a target to the given MSHR. This assumes it is in the miss queue. + * @param mshr The mshr to add a target to. + * @param req The target to add. + */ + void addTarget(MSHR *mshr, Packet * &pkt) + { + mq.allocateTarget(mshr, pkt); + } + + /** + * Allocate a MSHR to hold a list of targets to a block involved in a copy. + * If the block is marked done then the MSHR already holds the data to + * fill the block. Otherwise the block needs to be fetched. + * @param addr The address to buffer. + * @param asid The address space ID. + * @return A pointer to the allocated MSHR. + */ + MSHR* allocateTargetList(Addr addr, int asid); + +}; + +#endif //__MISS_QUEUE_HH__ |