mem: Remove the GHB prefetcher from the source tree

There are two primary issues with this code which make it deserving of deletion.

1) GHB is a way to structure a prefetcher, not a definitive type of prefetcher
2) This prefetcher isn't even structured like a GHB prefetcher.
   It's basically a worse version of the stride prefetcher.

It primarily serves to confuse new gem5 users and most functionality is already
present in the stride prefetcher.

diff --git a/src/mem/cache/prefetch/Prefetcher.py b/src/mem/cache/prefetch/Prefetcher.py
index c4b6b8845c8cf6f3e0f4fdd2ad61057541c42e31..6bb4e52d3706b4546351c86dffb7b60c37616ffe 100644 (file)
--- a/src/mem/cache/prefetch/Prefetcher.py
+++ b/src/mem/cache/prefetch/Prefetcher.py
@@ -69,11 +69,6 @@ class BasePrefetcher(ClockedObject):
          "Perform a tagged prefetch for instruction fetches always")
     sys = Param.System(Parent.any, "System this device belongs to")
 
-class GHBPrefetcher(BasePrefetcher):
-    type = 'GHBPrefetcher'
-    cxx_class = 'GHBPrefetcher'
-    cxx_header = "mem/cache/prefetch/ghb.hh"
-
 class StridePrefetcher(BasePrefetcher):
     type = 'StridePrefetcher'
     cxx_class = 'StridePrefetcher'

diff --git a/src/mem/cache/prefetch/SConscript b/src/mem/cache/prefetch/SConscript
index 61291f715e789c4cf93ca137c87d04d8cad99a85..cbb6c7a7a9ff27aa628f28649e96c46dcc3e1bb0 100644 (file)
--- a/src/mem/cache/prefetch/SConscript
+++ b/src/mem/cache/prefetch/SConscript
@@ -33,7 +33,6 @@ Import('*')
 SimObject('Prefetcher.py')
 
 Source('base.cc')
-Source('ghb.cc')
 Source('stride.cc')
 Source('tagged.cc')
 

diff --git a/src/mem/cache/prefetch/ghb.cc b/src/mem/cache/prefetch/ghb.cc
deleted file mode 100644 (file)
index e153c77..0000000
--- a/src/mem/cache/prefetch/ghb.cc
+++ /dev/null
@@ -1,97 +0,0 @@
-/*
- * Copyright (c) 2012-2013 ARM Limited
- * All rights reserved
- *
- * The license below extends only to copyright in the software and shall
- * not be construed as granting a license to any other intellectual
- * property including but not limited to intellectual property relating
- * to a hardware implementation of the functionality of the software
- * licensed hereunder.  You may use the software subject to the license
- * terms below provided that you ensure that this notice is replicated
- * unmodified and in its entirety in all distributions of the software,
- * modified or unmodified, in source code or in binary form.
- *
- * 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
- *          Steve Reinhardt
- */
-
-/**
- * @file
- * GHB Prefetcher implementation.
- */
-
-#include "base/trace.hh"
-#include "debug/HWPrefetch.hh"
-#include "mem/cache/prefetch/ghb.hh"
-
-void
-GHBPrefetcher::calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
-                                 std::list<Cycles> &delays)
-{
-    Addr blk_addr = pkt->getAddr() & ~(Addr)(blkSize-1);
-    bool is_secure = pkt->isSecure();
-    int master_id = useMasterId ? pkt->req->masterId() : 0;
-    assert(master_id < Max_Masters);
-
-    bool same_sec_state = true;
-    // Avoid activating prefetch if the security state is not
-    // consistent across requests
-    if (is_secure != lastMissIsSecure[master_id] ||
-        is_secure != secondLastMissIsSecure[master_id])
-        same_sec_state = false;
-
-    int new_stride = blk_addr - lastMissAddr[master_id];
-    int old_stride = lastMissAddr[master_id] - secondLastMissAddr[master_id];
-
-    secondLastMissAddr[master_id] = lastMissAddr[master_id];
-    secondLastMissIsSecure[master_id] = lastMissIsSecure[master_id];
-    lastMissAddr[master_id] = blk_addr;
-    lastMissIsSecure[master_id] = is_secure;
-
-    if (same_sec_state && new_stride == old_stride) {
-        for (int d = 1; d <= degree; d++) {
-            Addr new_addr = blk_addr + d * new_stride;
-            if (pageStop && !samePage(blk_addr, new_addr)) {
-                // Spanned the page, so now stop
-                pfSpanPage += degree - d + 1;
-                return;
-            } else {
-                addresses.push_back(new_addr);
-                delays.push_back(latency);
-            }
-        }
-    }
-}
-
-
-GHBPrefetcher*
-GHBPrefetcherParams::create()
-{
-   return new GHBPrefetcher(this);
-}

diff --git a/src/mem/cache/prefetch/ghb.hh b/src/mem/cache/prefetch/ghb.hh
deleted file mode 100644 (file)
index 9ddff11..0000000
--- a/src/mem/cache/prefetch/ghb.hh
+++ /dev/null
@@ -1,77 +0,0 @@
-/*
- * Copyright (c) 2012-2013 ARM Limited
- * All rights reserved
- *
- * The license below extends only to copyright in the software and shall
- * not be construed as granting a license to any other intellectual
- * property including but not limited to intellectual property relating
- * to a hardware implementation of the functionality of the software
- * licensed hereunder.  You may use the software subject to the license
- * terms below provided that you ensure that this notice is replicated
- * unmodified and in its entirety in all distributions of the software,
- * modified or unmodified, in source code or in binary form.
- *
- * 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.
- */
-
-#ifndef __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__
-#define __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__
-
-#include "mem/cache/prefetch/base.hh"
-#include "params/GHBPrefetcher.hh"
-
-class GHBPrefetcher : public BasePrefetcher
-{
-  protected:
-
-    static const int Max_Masters = 64;
-
-    Addr secondLastMissAddr[Max_Masters];
-    bool secondLastMissIsSecure[Max_Masters];
-    Addr lastMissAddr[Max_Masters];
-    bool lastMissIsSecure[Max_Masters];
-
-  public:
-    GHBPrefetcher(const Params *p)
-        : BasePrefetcher(p)
-    {
-    }
-
-    ~GHBPrefetcher() {}
-
-    void calculatePrefetch(PacketPtr &pkt, std::list<Addr> &addresses,
-                           std::list<Cycles> &delays);
-};
-
-#endif // __MEM_CACHE_PREFETCH_GHB_PREFETCHER_HH__