base: Make Bloom Filter counting by default

Since a boolean bool filter is a saturating bloom filter with a
single bit per entry, generalize them by using SatCounter instead
of int for the filter entries.

Change-Id: I7f54e28d54de5671e0770b02ed9161735e6bd339
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18877
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>

7 files changed, 10 insertions, 180 deletions

diff --git a/src/base/filters/BloomFilters.py b/src/base/filters/BloomFilters.py
index df0a894ab..b3460d747 100644
--- a/src/base/filters/BloomFilters.py
+++ b/src/base/filters/BloomFilters.py
@@ -42,6 +42,7 @@ class BloomFilterBase(SimObject):
     offset_bits = Param.Unsigned(6, "Number of bits in a cache line offset")
 
     # Most of the filters are booleans, and thus saturate on 1
+    num_bits = Param.Int(1, "Number of bits in a filter entry")
     threshold = Param.Int(1, "Value at which an entry is considered as set")
 
 class BloomFilterBlock(BloomFilterBase):
@@ -54,17 +55,6 @@ class BloomFilterBlock(BloomFilterBase):
     masks_sizes = VectorParam.Unsigned([Self.offset_bits, Self.offset_bits],
         "Size, in number of bits, of each mask")
 
-class BloomFilterLSBCounting(BloomFilterBase):
-    type = 'BloomFilterLSBCounting'
-    cxx_class = 'BloomFilter::LSBCounting'
-    cxx_header = "base/filters/lsb_counting_bloom_filter.hh"
-
-    # By default use 4-bit saturating counters
-    max_value = Param.Int(15, "Maximum value of the filter entries")
-
-    # We assume that isSet will return true only when the counter saturates
-    threshold = Self.max_value
-
 class BloomFilterMultiBitSel(BloomFilterBase):
     type = 'BloomFilterMultiBitSel'
     cxx_class = 'BloomFilter::MultiBitSel'
diff --git a/src/base/filters/SConscript b/src/base/filters/SConscript
index 4c02ff122..254531203 100644
--- a/src/base/filters/SConscript
+++ b/src/base/filters/SConscript
@@ -37,6 +37,5 @@ SimObject('BloomFilters.py')
 Source('block_bloom_filter.cc')
 Source('bulk_bloom_filter.cc')
 Source('h3_bloom_filter.cc')
-Source('lsb_counting_bloom_filter.cc')
 Source('multi_bit_sel_bloom_filter.cc')
 Source('multi_bloom_filter.cc')
diff --git a/src/base/filters/base.hh b/src/base/filters/base.hh
index 1ce853979..fa618fe84 100644
--- a/src/base/filters/base.hh
+++ b/src/base/filters/base.hh
@@ -35,6 +35,7 @@
 #include <vector>
 
 #include "base/intmath.hh"
+#include "base/sat_counter.hh"
 #include "base/types.hh"
 #include "params/BloomFilterBase.hh"
 #include "sim/sim_object.hh"
@@ -48,7 +49,7 @@ class Base : public SimObject
     const unsigned offsetBits;
 
     /** The filter itself. */
-    std::vector<int> filter;
+    std::vector<SatCounter> filter;
 
     /** Number of bits needed to represent the size of the filter. */
     const int sizeBits;
@@ -61,7 +62,8 @@ class Base : public SimObject
      * Create and clear the filter.
      */
     Base(const BloomFilterBaseParams* p)
-        : SimObject(p), offsetBits(p->offset_bits), filter(p->size),
+        : SimObject(p), offsetBits(p->offset_bits),
+          filter(p->size, SatCounter(p->num_bits)),
           sizeBits(floorLog2(p->size)), setThreshold(p->threshold)
     {
         clear();
@@ -74,7 +76,7 @@ class Base : public SimObject
     virtual void clear()
     {
         for (auto& entry : filter) {
-            entry = 0;
+            entry.reset();
         }
     }
 
@@ -89,7 +91,7 @@ class Base : public SimObject
     {
         assert(filter.size() == other->filter.size());
         for (int i = 0; i < filter.size(); ++i){
-            filter[i] |= other->filter[i];
+            filter[i] += other->filter[i];
         }
     }
 
diff --git a/src/base/filters/block_bloom_filter.cc b/src/base/filters/block_bloom_filter.cc
index 45e3b725e..890ada84a 100644
--- a/src/base/filters/block_bloom_filter.cc
+++ b/src/base/filters/block_bloom_filter.cc
@@ -63,13 +63,13 @@ Block::~Block()
 void
 Block::set(Addr addr)
 {
-    filter[hash(addr)] = 1;
+    filter[hash(addr)]++;
 }
 
 void
 Block::unset(Addr addr)
 {
-    filter[hash(addr)] = 0;
+    filter[hash(addr)]--;
 }
 
 int
diff --git a/src/base/filters/lsb_counting_bloom_filter.cc b/src/base/filters/lsb_counting_bloom_filter.cc
deleted file mode 100644
index 16f858f01..000000000
--- a/src/base/filters/lsb_counting_bloom_filter.cc
+++ /dev/null
@@ -1,98 +0,0 @@
-/*
- * Copyright (c) 2019 Inria
- * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
- * 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: Daniel Carvalho
- */
-
-#include "base/filters/lsb_counting_bloom_filter.hh"
-
-#include "base/bitfield.hh"
-#include "params/BloomFilterLSBCounting.hh"
-
-namespace BloomFilter {
-
-LSBCounting::LSBCounting(
-    const BloomFilterLSBCountingParams* p)
-    : Base(p), maxValue(p->max_value)
-{
-}
-
-LSBCounting::~LSBCounting()
-{
-}
-
-void
-LSBCounting::merge(const Base* other)
-{
-    auto* cast_other = static_cast<const LSBCounting*>(other);
-    assert(filter.size() == cast_other->filter.size());
-    for (int i = 0; i < filter.size(); ++i){
-        if (filter[i] < maxValue - cast_other->filter[i]) {
-            filter[i] += cast_other->filter[i];
-        } else {
-            filter[i] = maxValue;
-        }
-    }
-}
-
-void
-LSBCounting::set(Addr addr)
-{
-    const int i = hash(addr);
-    if (filter[i] < maxValue)
-        filter[i] += 1;
-}
-
-void
-LSBCounting::unset(Addr addr)
-{
-    const int i = hash(addr);
-    if (filter[i] > 0)
-        filter[i] -= 1;
-}
-
-int
-LSBCounting::getCount(Addr addr) const
-{
-    return filter[hash(addr)];
-}
-
-int
-LSBCounting::hash(Addr addr) const
-{
-    return bits(addr, offsetBits + sizeBits - 1, offsetBits);
-}
-
-} // namespace BloomFilter
-
-BloomFilter::LSBCounting*
-BloomFilterLSBCountingParams::create()
-{
-    return new BloomFilter::LSBCounting(this);
-}
-
diff --git a/src/base/filters/lsb_counting_bloom_filter.hh b/src/base/filters/lsb_counting_bloom_filter.hh
deleted file mode 100644
index 6da6fd681..000000000
--- a/src/base/filters/lsb_counting_bloom_filter.hh
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright (c) 2019 Inria
- * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
- * 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: Daniel Carvalho
- */
-
-#ifndef __BASE_FILTERS_LSB_COUNTING_BLOOM_FILTER_HH__
-#define __BASE_FILTERS_LSB_COUNTING_BLOOM_FILTER_HH__
-
-#include "base/filters/base.hh"
-
-struct BloomFilterLSBCountingParams;
-
-namespace BloomFilter {
-
-class LSBCounting : public Base
-{
-  public:
-    LSBCounting(const BloomFilterLSBCountingParams* p);
-    ~LSBCounting();
-
-    void merge(const Base* other) override;
-    void set(Addr addr) override;
-    void unset(Addr addr) override;
-
-    int getCount(Addr addr) const override;
-
-  private:
-    int hash(Addr addr) const;
-
-    /** Maximum value of the filter entries. */
-    const int maxValue;
-};
-
-} // namespace BloomFilter
-
-#endif //__BASE_FILTERS_LSB_COUNTING_BLOOM_FILTER_HH__
diff --git a/src/base/filters/multi_bit_sel_bloom_filter.cc b/src/base/filters/multi_bit_sel_bloom_filter.cc
index efd20c315..6fa99fec6 100644
--- a/src/base/filters/multi_bit_sel_bloom_filter.cc
+++ b/src/base/filters/multi_bit_sel_bloom_filter.cc
@@ -58,8 +58,7 @@ void
 MultiBitSel::set(Addr addr)
 {
     for (int i = 0; i < numHashes; i++) {
-        int idx = hash(addr, i);
-        filter[idx] = 1;
+        filter[hash(addr, i)]++;
     }
 }