mem-cache: Revert "Prefetchers Improvements"

Reverts PR https://github.com/gem5/gem5/pull/564

Reverts commits:

* 047a494c2b
* 2abd65c270
* 38045d7a25
* 6416304e07
* 8598764a03

Change-Id: Id523acc1778c3f827637302a6465f5a9e539d6b5

src/mem/cache/Cache.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2012-2013, 2015, 2018, 2022 Arm Limited
+# Copyright (c) 2012-2013, 2015, 2018 ARM Limited
 # All rights reserved.
 #
 # The license below extends only to copyright in the software and shall
@@ -112,7 +112,7 @@ class BaseCache(ClockedObject):
         "Notify the hardware prefetcher on every access (not just misses)",
     )
     prefetch_on_pf_hit = Param.Bool(
-        True, "Notify the hardware prefetcher on hit on prefetched lines"
+        False, "Notify the hardware prefetcher on hit on prefetched lines"
     )
 
     tags = Param.BaseTags(BaseSetAssoc(), "Tag store")

src/mem/cache/prefetch/Prefetcher.py

@@ -1,4 +1,4 @@
-# Copyright (c) 2012, 2014, 2019, 2022 Arm Limited
+# Copyright (c) 2012, 2014, 2019 ARM Limited
 # All rights reserved.
 #
 # The license below extends only to copyright in the software and shall
@@ -192,13 +192,6 @@ class StridePrefetcher(QueuedPrefetcher):
     use_requestor_id = Param.Bool(True, "Use requestor id based history")
 
     degree = Param.Int(4, "Number of prefetches to generate")
-    distance = Param.Unsigned(
-        0,
-        "How far ahead of the demand stream to start prefetching. "
-        "Skip this number of strides ahead of the first identified prefetch, "
-        "then generate `degree` prefetches at `stride` intervals. "
-        "A value of zero indicates no skip.",
-    )
 
     table_assoc = Param.Int(4, "Associativity of the PC table")
     table_entries = Param.MemorySize("64", "Number of entries of the PC table")

src/mem/cache/prefetch/base.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013-2014, 2022 Arm Limited
+ * Copyright (c) 2013-2014 ARM Limited
  * All rights reserved.
  *
  * The license below extends only to copyright in the software and shall
@@ -245,7 +245,6 @@ Base::probeNotify(const PacketPtr &pkt, bool miss)
     // operations or for writes that we are coaslescing.
     if (pkt->cmd.isSWPrefetch()) return;
     if (pkt->req->isCacheMaintenance()) return;
-    if (pkt->isCleanEviction()) return;
     if (pkt->isWrite() && cache != nullptr && cache->coalesce()) return;
     if (!pkt->req->hasPaddr()) {
         panic("Request must have a physical address");

src/mem/cache/prefetch/queued.cc

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2015, 2022 Arm Limited
+ * Copyright (c) 2014-2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -178,7 +178,7 @@ Queued::notify(const PacketPtr &pkt, const PrefetchInfo &pfi)
     if (queueSquash) {
         auto itr = pfq.begin();
         while (itr != pfq.end()) {
-            if (blockAddress(itr->pfInfo.getAddr()) == blk_addr &&
+            if (itr->pfInfo.getAddr() == blk_addr &&
                 itr->pfInfo.isSecure() == is_secure) {
                 DPRINTF(HWPrefetch, "Removing pf candidate addr: %#x "
                         "(cl: %#x), demand request going to the same addr\n",

src/mem/cache/prefetch/stride.cc

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018 Inria
- * Copyright (c) 2012-2013, 2015, 2022-2023 Arm Limited
+ * Copyright (c) 2012-2013, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -84,7 +84,6 @@ Stride::Stride(const StridePrefetcherParams &p)
     threshConf(p.confidence_threshold/100.0),
     useRequestorId(p.use_requestor_id),
     degree(p.degree),
-    distance(p.distance),
     pcTableInfo(p.table_assoc, p.table_entries, p.table_indexing_policy,
         p.table_replacement_policy)
 {
@@ -168,16 +167,16 @@ Stride::calculatePrefetch(const PrefetchInfo &pfi,
             return;
         }
 
-        // Round strides up to atleast 1 cacheline
-        int prefetch_stride = new_stride;
-        if (abs(new_stride) < blkSize) {
-            prefetch_stride = (new_stride < 0) ? -blkSize : blkSize;
-        }
-
-        Addr new_addr = pf_addr + distance * prefetch_stride;
         // Generate up to degree prefetches
         for (int d = 1; d <= degree; d++) {
-            addresses.push_back(AddrPriority(new_addr += prefetch_stride, 0));
+            // Round strides up to atleast 1 cacheline
+            int prefetch_stride = new_stride;
+            if (abs(new_stride) < blkSize) {
+                prefetch_stride = (new_stride < 0) ? -blkSize : blkSize;
+            }
+
+            Addr new_addr = pf_addr + d * prefetch_stride;
+            addresses.push_back(AddrPriority(new_addr, 0));
         }
     } else {
         // Miss in table

src/mem/cache/prefetch/stride.hh

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2018 Inria
- * Copyright (c) 2012-2013, 2015, 2022 Arm Limited
+ * Copyright (c) 2012-2013, 2015 ARM Limited
  * All rights reserved
  *
  * The license below extends only to copyright in the software and shall
@@ -105,8 +105,6 @@ class Stride : public Queued
 
     const int degree;
 
-    const int distance;
-
     /**
      * Information used to create a new PC table. All of them behave equally.
      */