xref: /gem5/src/base/filters/bulk_bloom_filter.hh

/*
 * 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_BULK_BLOOM_FILTER_HH__
#define __BASE_FILTERS_BULK_BLOOM_FILTER_HH__

#include "base/filters/multi_bit_sel_bloom_filter.hh"

struct BloomFilterBulkParams;

namespace BloomFilter {

/**
 * Implementation of the bloom filter, as described in "Bulk Disambiguation of
 * Speculative Threads in Multiprocessors", by Ceze, Luis, et al.
 * The number of hashes indicates the number of c bitfields.
 */
class Bulk : public MultiBitSel
{
  public:
    Bulk(const BloomFilterBulkParams* p);
    ~Bulk();

  protected:
    int hash(Addr addr, int hash_number) const override;

  private:
    /** Permutes the address to generate its signature. */
    Addr permute(Addr addr) const;

    /**
     * Number of bits used per sector. The filter is split into sectors,
     * each of which with its own hash function. When an address is hashed
     * all sectors are parsed to generate c indexes. These indexes are then
     * used to find the respective v indexes in the main filter.
     */
    const int sectorBits;
};

} // namespace BloomFilter

#endif // __BASE_FILTERS_BULK_BLOOM_FILTER_HH__