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+/*
+ * Copyright (c) 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: Ron Dreslinski
+ */
+
+/**
+ * @file
+ * Describes a ghb prefetcher based on template policies.
+ */
+
+#ifndef __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__
+#define __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__
+
+#include "base/misc.hh" // fatal, panic, and warn
+
+#include "mem/cache/prefetch/prefetcher.hh"
+
+/**
+ * A template-policy based cache. The behavior of the cache can be altered by
+ * supplying different template policies. TagStore handles all tag and data
+ * storage @sa TagStore. Buffering handles all misses and writes/writebacks
+ * @sa MissQueue. Coherence handles all coherence policy details @sa
+ * UniCoherence, SimpleMultiCoherence.
+ */
+template <class TagStore, class Buffering>
+class GHBPrefetcher : public Prefetcher<TagStore, Buffering>
+{
+ protected:
+
+ Buffering* mq;
+ TagStore* tags;
+
+ Addr second_last_miss_addr[64/*MAX_CPUS*/];
+ Addr last_miss_addr[64/*MAX_CPUS*/];
+
+ Tick latency;
+ int degree;
+ bool useCPUId;
+
+ public:
+
+ GHBPrefetcher(int size, bool pageStop, bool serialSquash,
+ bool cacheCheckPush, bool onlyData,
+ Tick latency, int degree, bool useCPUId)
+ :Prefetcher<TagStore, Buffering>(size, pageStop, serialSquash,
+ cacheCheckPush, onlyData),
+ latency(latency), degree(degree), useCPUId(useCPUId)
+ {
+ }
+
+ ~GHBPrefetcher() {}
+
+ void calculatePrefetch(Packet * &pkt, std::list<Addr> &addresses,
+ std::list<Tick> &delays)
+ {
+ Addr blkAddr = pkt->getAddr() & ~(Addr)(this->blkSize-1);
+ int cpuID = pkt->req->getCpuNum();
+ if (!useCPUId) cpuID = 0;
+
+
+ int new_stride = blkAddr - last_miss_addr[cpuID];
+ int old_stride = last_miss_addr[cpuID] -
+ second_last_miss_addr[cpuID];
+
+ second_last_miss_addr[cpuID] = last_miss_addr[cpuID];
+ last_miss_addr[cpuID] = blkAddr;
+
+ if (new_stride == old_stride) {
+ for (int d=1; d <= degree; d++) {
+ Addr newAddr = blkAddr + d * new_stride;
+ if (this->pageStop &&
+ (blkAddr & ~(TheISA::VMPageSize - 1)) !=
+ (newAddr & ~(TheISA::VMPageSize - 1)))
+ {
+ //Spanned the page, so now stop
+ this->pfSpanPage += degree - d + 1;
+ return;
+ }
+ else
+ {
+ addresses.push_back(newAddr);
+ delays.push_back(latency);
+ }
+ }
+ }
+ }
+};
+
+#endif // __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__