gem5  v21.1.0.2
multi_bit_sel_bloom_filter.cc
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29 
31 
32 #include <limits>
33 
34 #include "base/bitfield.hh"
35 #include "base/logging.hh"
36 #include "params/BloomFilterMultiBitSel.hh"
37 
38 namespace gem5
39 {
40 
41 GEM5_DEPRECATED_NAMESPACE(BloomFilter, bloom_filter);
42 namespace bloom_filter
43 {
44 
45 MultiBitSel::MultiBitSel(const BloomFilterMultiBitSelParams &p)
46  : Base(p), numHashes(p.num_hashes),
47  parFilterSize(p.size / numHashes),
48  isParallel(p.is_parallel), skipBits(p.skip_bits)
49 {
50  if (p.size % numHashes) {
51  fatal("Can't divide filter (%d) in %d equal portions", p.size,
52  numHashes);
53  }
54 }
55 
57 {
58 }
59 
60 void
62 {
63  for (int i = 0; i < numHashes; i++) {
64  filter[hash(addr, i)]++;
65  }
66 }
67 
68 int
70 {
71  int count = 0;
72  for (int i=0; i < numHashes; i++) {
73  count += filter[hash(addr, i)];
74  }
75  return count;
76 }
77 
78 int
79 MultiBitSel::hash(Addr addr, int hash_number) const
80 {
81  uint64_t value = bits(addr, std::numeric_limits<Addr>::digits - 1,
82  offsetBits) >> skipBits;
83  const int max_bits = std::numeric_limits<Addr>::digits - offsetBits;
84  int result = 0;
85  int bit, i;
86 
87  for (i = 0; i < sizeBits; i++) {
88  bit = (hash_number + numHashes * i) % max_bits;
89  if (value & (1 << bit)) {
90  result += 1 << i;
91  }
92  }
93 
94  if (isParallel) {
95  return (result % parFilterSize) + hash_number * parFilterSize;
96  } else {
97  return result % filter.size();
98  }
99 }
100 
101 } // namespace bloom_filter
102 } // namespace gem5
103 
gem5::bloom_filter::MultiBitSel::getCount
int getCount(Addr addr) const override
Get the value stored in the corresponding filter entry of an address.
Definition: multi_bit_sel_bloom_filter.cc:69
fatal
#define fatal(...)
This implements a cprintf based fatal() function.
Definition: logging.hh:189
gem5::bloom_filter::MultiBitSel::parFilterSize
const int parFilterSize
Size of the filter when doing parallel hashing.
Definition: multi_bit_sel_bloom_filter.hh:70
gem5::bloom_filter::MultiBitSel::hash
virtual int hash(Addr addr, int hash_number) const
Apply the selected the hash functions to an address.
Definition: multi_bit_sel_bloom_filter.cc:79
gem5::bloom_filter::MultiBitSel::numHashes
const int numHashes
Number of hashes.
Definition: multi_bit_sel_bloom_filter.hh:67
gem5::bloom_filter::Base::filter
std::vector< SatCounter8 > filter
The filter itself.
Definition: base.hh:56
gem5::bloom_filter::Base
Definition: base.hh:49
gem5::bloom_filter::Base::offsetBits
const unsigned offsetBits
Number of LSB bits to ignore from the the addresses.
Definition: base.hh:53
gem5::bloom_filter::Base::sizeBits
const int sizeBits
Number of bits needed to represent the size of the filter.
Definition: base.hh:59
gem5::bloom_filter::MultiBitSel::~MultiBitSel
~MultiBitSel()
Definition: multi_bit_sel_bloom_filter.cc:56
gem5::bloom_filter::MultiBitSel::MultiBitSel
MultiBitSel(const BloomFilterMultiBitSelParams &p)
Definition: multi_bit_sel_bloom_filter.cc:45
gem5::ArmISA::i
Bitfield< 7 > i
Definition: misc_types.hh:66
bitfield.hh
gem5::X86ISA::count
count
Definition: misc.hh:709
multi_bit_sel_bloom_filter.hh
gem5::MipsISA::p
Bitfield< 0 > p
Definition: pra_constants.hh:326
gem5::bloom_filter::MultiBitSel::set
void set(Addr addr) override
Perform the filter specific function to set the corresponding entries (can be multiple) of an address...
Definition: multi_bit_sel_bloom_filter.cc:61
gem5::bloom_filter::MultiBitSel::skipBits
const int skipBits
Bit offset from block number.
Definition: multi_bit_sel_bloom_filter.hh:80
gem5::bloom_filter::MultiBitSel::isParallel
const bool isParallel
Whether hashing should be performed in parallel.
Definition: multi_bit_sel_bloom_filter.hh:73
gem5::bits
constexpr T bits(T val, unsigned first, unsigned last)
Extract the bitfield from position 'first' to 'last' (inclusive) from 'val' and right justify it.
Definition: bitfield.hh:76
gem5::Addr
uint64_t Addr
Address type This will probably be moved somewhere else in the near future.
Definition: types.hh:147
gem5::GEM5_DEPRECATED_NAMESPACE
GEM5_DEPRECATED_NAMESPACE(GuestABI, guest_abi)
logging.hh
gem5
Reference material can be found at the JEDEC website: UFS standard http://www.jedec....
Definition: decoder.cc:40
gem5::X86ISA::addr
Bitfield< 3 > addr
Definition: types.hh:84

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