diff options
Diffstat (limited to 'src/mem/cache/base.hh')
| -rw-r--r-- | src/mem/cache/base.hh | 57 |
1 files changed, 31 insertions, 26 deletions
diff --git a/src/mem/cache/base.hh b/src/mem/cache/base.hh index c4e39716f..87948294e 100644 --- a/src/mem/cache/base.hh +++ b/src/mem/cache/base.hh @@ -454,9 +454,11 @@ class BaseCache : public ClockedObject * @param pkt The memory request to perform. * @param blk The cache block to be updated. * @param lat The latency of the access. + * @param writebacks List for any writebacks that need to be performed. * @return Boolean indicating whether the request was satisfied. */ - virtual bool access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat); + virtual bool access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat, + PacketList &writebacks); /* * Handle a timing request that hit in the cache @@ -549,9 +551,11 @@ class BaseCache : public ClockedObject * * @param pkt The packet with the requests * @param blk The referenced block + * @param writebacks A list with packets for any performed writebacks * @return Cycles for handling the request */ - virtual Cycles handleAtomicReqMiss(PacketPtr pkt, CacheBlk *&blk) = 0; + virtual Cycles handleAtomicReqMiss(PacketPtr pkt, CacheBlk *&blk, + PacketList &writebacks) = 0; /** * Performs the access specified by the request. @@ -591,18 +595,13 @@ class BaseCache : public ClockedObject /** * Insert writebacks into the write buffer - * - * @param pkt The writeback packet. - * @param forward_time Tick to which the writeback should be scheduled. */ - virtual void doWritebacks(PacketPtr pkt, Tick forward_time) = 0; + virtual void doWritebacks(PacketList& writebacks, Tick forward_time) = 0; /** - * Send writebacks down the memory hierarchy in atomic mode. - * - * @param pkt The writeback packet. + * Send writebacks down the memory hierarchy in atomic mode */ - virtual void doWritebacksAtomic(PacketPtr pkt) = 0; + virtual void doWritebacksAtomic(PacketList& writebacks) = 0; /** * Create an appropriate downstream bus request packet. @@ -648,7 +647,8 @@ class BaseCache : public ClockedObject */ void writebackTempBlockAtomic() { assert(tempBlockWriteback != nullptr); - doWritebacksAtomic(tempBlockWriteback); + PacketList writebacks{tempBlockWriteback}; + doWritebacksAtomic(writebacks); tempBlockWriteback = nullptr; } @@ -680,12 +680,11 @@ class BaseCache : public ClockedObject * * @param blk The block to be overwriten. * @param data A pointer to the data to be compressed (blk's new data). - * @param delay The delay until the packet's metadata is present. - * @param tag_latency Latency to access the tags of the replacement victim. + * @param writebacks List for any writebacks that need to be performed. * @return Whether operation is successful or not. */ bool updateCompressionData(CacheBlk *blk, const uint64_t* data, - uint32_t delay, Cycles tag_latency); + PacketList &writebacks); /** * Perform any necessary updates to the block and perform any data @@ -718,27 +717,34 @@ class BaseCache : public ClockedObject * Populates a cache block and handles all outstanding requests for the * satisfied fill request. This version takes two memory requests. One * contains the fill data, the other is an optional target to satisfy. + * Note that the reason we return a list of writebacks rather than + * inserting them directly in the write buffer is that this function + * is called by both atomic and timing-mode accesses, and in atomic + * mode we don't mess with the write buffer (we just perform the + * writebacks atomically once the original request is complete). * * @param pkt The memory request with the fill data. * @param blk The cache block if it already exists. + * @param writebacks List for any writebacks that need to be performed. * @param allocate Whether to allocate a block or use the temp block * @return Pointer to the new cache block. */ - CacheBlk *handleFill(PacketPtr pkt, CacheBlk *blk, bool allocate); + CacheBlk *handleFill(PacketPtr pkt, CacheBlk *blk, + PacketList &writebacks, bool allocate); /** - * Allocate a new block for the packet's data. The victim block might be - * valid, and thus the necessary writebacks are done. May return nullptr - * if there are no replaceable blocks. If a replaceable block is found, - * it inserts the new block in its place. The new block, however, is not - * set as valid yet. + * Allocate a new block and perform any necessary writebacks + * + * Find a victim block and if necessary prepare writebacks for any + * existing data. May return nullptr if there are no replaceable + * blocks. If a replaceable block is found, it inserts the new block in + * its place. The new block, however, is not set as valid yet. * * @param pkt Packet holding the address to update - * @param tag_latency Latency to access the tags of the replacement victim. + * @param writebacks A list of writeback packets for the evicted blocks * @return the allocated block */ - CacheBlk *allocateBlock(const PacketPtr pkt, Cycles tag_latency); - + CacheBlk *allocateBlock(const PacketPtr pkt, PacketList &writebacks); /** * Evict a cache block. * @@ -755,10 +761,9 @@ class BaseCache : public ClockedObject * Performs a writeback if necesssary and invalidates the block * * @param blk Block to invalidate - * @param forward_time Tick to which the writeback should be scheduled if - * in timing mode. + * @param writebacks Return a list of packets with writebacks */ - void evictBlock(CacheBlk *blk, Tick forward_time); + void evictBlock(CacheBlk *blk, PacketList &writebacks); /** * Invalidate a cache block. |