src/mem/ruby/filters/MultiGrainBloomFilter.cc

   1 /*
   2  * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "mem/ruby/filters/MultiGrainBloomFilter.hh"
  30
  31 #include "base/bitfield.hh"
  32 #include "params/MultiGrainBloomFilter.hh"
  33
  34 MultiGrainBloomFilter::MultiGrainBloomFilter(
  35     const MultiGrainBloomFilterParams* p)
  36     : AbstractBloomFilter(p), pageFilter(p->page_filter_size),
  37       pageFilterSizeBits(floorLog2(p->page_filter_size))
  38 {
  39 }
  40
  41 MultiGrainBloomFilter::~MultiGrainBloomFilter()
  42 {
  43 }
  44
  45 void
  46 MultiGrainBloomFilter::clear()
  47 {
  48     AbstractBloomFilter::clear();
  49     for (auto& entry : pageFilter){
  50         entry = 0;
  51     }
  52 }
  53
  54 void
  55 MultiGrainBloomFilter::set(Addr addr)
  56 {
  57     int i = hash(addr);
  58     assert(i < filter.size());
  59     assert(pageHash(addr) < pageFilter.size());
  60     filter[i] = 1;
  61     pageFilter[i] = 1;
  62
  63 }
  64
  65 int
  66 MultiGrainBloomFilter::getCount(Addr addr) const
  67 {
  68     int i = hash(addr);
  69     assert(i < filter.size());
  70     assert(pageHash(addr) < pageFilter.size());
  71     return filter[i] + pageFilter[i];
  72 }
  73
  74 int
  75 MultiGrainBloomFilter::getTotalCount() const
  76 {
  77     int count = AbstractBloomFilter::getTotalCount();
  78
  79     for (const auto& entry : pageFilter) {
  80         count += entry;
  81     }
  82
  83     return count;
  84 }
  85
  86 int
  87 MultiGrainBloomFilter::hash(Addr addr) const
  88 {
  89     // grap a chunk of bits after byte offset
  90     return bits(addr, offsetBits + sizeBits - 1, offsetBits);
  91 }
  92
  93 int
  94 MultiGrainBloomFilter::pageHash(Addr addr) const
  95 {
  96     int num_bits = offsetBits + sizeBits - 1;
  97
  98     // grap a chunk of bits after first chunk
  99     return bits(addr, num_bits + pageFilterSizeBits - 1, num_bits);
 100 }
 101
 102 MultiGrainBloomFilter*
 103 MultiGrainBloomFilterParams::create()
 104 {
 105     return new MultiGrainBloomFilter(this);
 106 }