From 3a3ad05aca43fb4dae1a0a9785549dcfc385af0d Mon Sep 17 00:00:00 2001
From: Javier Bueno <javier.bueno@metempsy.com>
Date: Thu, 29 Nov 2018 16:59:16 +0100
Subject: mem-cache: Signature Path Prefetcher

Related paper:
  Lookahead Prefetching with Signature Path
  J Kim, PV Gratz, ALN Reddy
  The 2nd Data Prefetching Championship (DPC2), 2015

Change-Id: I2319be2fa409f955f65e1bf1e1bb2d6d9a4fea11
Reviewed-on: https://gem5-review.googlesource.com/c/14737
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
---
 src/mem/cache/prefetch/associative_set_impl.hh | 119 +++++++++++++++++++++++++
 1 file changed, 119 insertions(+)
 create mode 100644 src/mem/cache/prefetch/associative_set_impl.hh

(limited to 'src/mem/cache/prefetch/associative_set_impl.hh')

diff --git a/src/mem/cache/prefetch/associative_set_impl.hh b/src/mem/cache/prefetch/associative_set_impl.hh
new file mode 100644
index 000000000..5e6e7c585
--- /dev/null
+++ b/src/mem/cache/prefetch/associative_set_impl.hh
@@ -0,0 +1,119 @@
+/**
+ * Copyright (c) 2018 Metempsy Technology Consulting
+ * 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: Javier Bueno
+ */
+
+#ifndef __CACHE_PREFETCH_ASSOCIATIVE_SET_IMPL_HH__
+#define __CACHE_PREFETCH_ASSOCIATIVE_SET_IMPL_HH__
+
+#include "mem/cache/prefetch/associative_set.hh"
+
+template<class Entry>
+AssociativeSet<Entry>::AssociativeSet(int assoc, int num_entries,
+        BaseIndexingPolicy *idx_policy, BaseReplacementPolicy *rpl_policy,
+        Entry const &init_value)
+  : associativity(assoc), numEntries(num_entries), indexingPolicy(idx_policy),
+    replacementPolicy(rpl_policy), entries(numEntries, init_value)
+{
+    fatal_if(!isPowerOf2(num_entries), "The number of entries of an "
+             "AssociativeSet<> must be a power of 2");
+    fatal_if(!isPowerOf2(assoc), "The associativity of an AssociativeSet<> "
+             "must be a power of 2");
+    for (unsigned int entry_idx = 0; entry_idx < numEntries; entry_idx += 1) {
+        Entry* entry = &entries[entry_idx];
+        indexingPolicy->setEntry(entry, entry_idx);
+        entry->replacementData = replacementPolicy->instantiateEntry();
+    }
+}
+
+template<class Entry>
+Entry*
+AssociativeSet<Entry>::findEntry(Addr addr, bool is_secure) const
+{
+    Addr tag = indexingPolicy->extractTag(addr);
+    const std::vector<ReplaceableEntry*> selected_entries =
+        indexingPolicy->getPossibleEntries(addr);
+
+    for (const auto& location : selected_entries) {
+        Entry* entry = static_cast<Entry *>(location);
+        if ((entry->getTag() == tag) && entry->isValid() &&
+            entry->isSecure() == is_secure) {
+            return entry;
+        }
+    }
+    return nullptr;
+}
+
+template<class Entry>
+void
+AssociativeSet<Entry>::accessEntry(Entry *entry)
+{
+    replacementPolicy->touch(entry->replacementData);
+}
+
+template<class Entry>
+Entry*
+AssociativeSet<Entry>::findVictim(Addr addr)
+{
+    // Get possible entries to be victimized
+    const std::vector<ReplaceableEntry*> selected_entries =
+        indexingPolicy->getPossibleEntries(addr);
+    Entry* victim = static_cast<Entry*>(replacementPolicy->getVictim(
+                            selected_entries));
+    // There is only one eviction for this replacement
+    victim->reset();
+    return victim;
+}
+
+
+template<class Entry>
+std::vector<Entry *>
+AssociativeSet<Entry>::getPossibleEntries(const Addr addr) const
+{
+    std::vector<ReplaceableEntry *> selected_entries =
+        indexingPolicy->getPossibleEntries(addr);
+    std::vector<Entry *> entries(selected_entries.size(), nullptr);
+
+    unsigned int idx = 0;
+    for (auto &entry : selected_entries) {
+        entries[idx++] = static_cast<Entry *>(entry);
+    }
+    return entries;
+}
+
+template<class Entry>
+void
+AssociativeSet<Entry>::insertEntry(Addr addr, bool is_secure, Entry* entry)
+{
+   entry->setValid();
+   entry->setTag(indexingPolicy->extractTag(addr));
+   entry->setSecure(is_secure);
+   replacementPolicy->reset(entry->replacementData);
+}
+
+#endif//__CACHE_PREFETCH_ASSOCIATIVE_SET_IMPL_HH__
-- 
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