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Diffstat (limited to 'src/mem/cache/miss/blocking_buffer.hh')
| -rw-r--r-- | src/mem/cache/miss/blocking_buffer.hh | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/src/mem/cache/miss/blocking_buffer.hh b/src/mem/cache/miss/blocking_buffer.hh new file mode 100644 index 000000000..39a06a377 --- /dev/null +++ b/src/mem/cache/miss/blocking_buffer.hh @@ -0,0 +1,256 @@ +/* + * 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 simple buffer for a blocking cache. + */ + +#ifndef __BLOCKING_BUFFER_HH__ +#define __BLOCKING_BUFFER_HH__ + +#include <vector> + +#include "mem/cache/miss/mshr.hh" +#include "base/statistics.hh" + +class BaseCache; +class BasePrefetcher; + +/** + * Miss and writeback storage for a blocking cache. + */ +class BlockingBuffer +{ +protected: + /** Miss storage. */ + MSHR miss; + /** WB storage. */ + MSHR wb; + + //Params + + /** Allocate on write misses. */ + const bool writeAllocate; + + /** Pointer to the parent cache. */ + BaseCache* cache; + + BasePrefetcher* prefetcher; + + /** Block size of the parent cache. */ + int blkSize; + + // Statistics + /** + * @addtogroup CacheStatistics + * @{ + */ + /** Number of blocks written back per thread. */ + Stats::Vector<> writebacks; + + /** + * @} + */ + +public: + /** + * Builds and initializes this buffer. + * @param write_allocate If true, treat write misses the same as reads. + */ + BlockingBuffer(bool write_allocate) + : writeAllocate(write_allocate) + { + } + + /** + * 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. Requests the bus and marks the cache as + * blocked. + * @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) + { + fatal("Unimplemented"); + } + + /** + * 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); + + /** + * Frees the resources of the request and unblock the cache. + * @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 req->getThreadNum()ber The thread number of the requests to squash. + */ + void squash(int threadNum); + + /** + * Return the current number of outstanding misses. + * @return the number of outstanding misses. + */ + int getMisses() + { + return miss.getNumTargets(); + } + + /** + * Searches for the supplied address in the miss "queue". + * @param addr The address to look for. + * @param asid The address space id. + * @return A pointer to miss if it matches. + */ + MSHR* findMSHR(Addr addr, int asid) + { + if (miss.addr == addr && miss.pkt) + return &miss; + return NULL; + } + + /** + * Searches for the supplied address in the write buffer. + * @param addr The address to look for. + * @param asid The address space id. + * @param writes List of pointers to the matching writes. + * @return True if there is a matching write. + */ + bool findWrites(Addr addr, int asid, std::vector<MSHR*>& writes) + { + if (wb.addr == addr && wb.pkt) { + writes.push_back(&wb); + return true; + } + return false; + } + + + + /** + * Perform a writeback of dirty data to the given address. + * @param addr The address to write to. + * @param asid The address space id. + * @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 a 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() + { + return !miss.inService || !wb.inService; + } + + /** + * 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) + { + fatal("Shouldn't call this on a blocking buffer."); + } + + /** + * Dummy implmentation. + */ + MSHR* allocateTargetList(Addr addr, int asid) + { + fatal("Unimplemented"); + } +}; + +#endif // __BLOCKING_BUFFER_HH__ |