Merge #8895: Better SigCache Implementation
67dac4e Add unit tests for the CuckooCache (Jeremy Rubin) c9e69fb Add CuckooCache implementation and replace the sigcache map_type with it (Jeremy Rubin)
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@ -59,6 +59,7 @@ BITCOIN_TESTS =\
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test/coins_tests.cpp \
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test/compress_tests.cpp \
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test/crypto_tests.cpp \
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test/cuckoocache_tests.cpp \
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test/DoS_tests.cpp \
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test/getarg_tests.cpp \
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test/governance_validators_tests.cpp \
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src/cuckoocache.h
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457
src/cuckoocache.h
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@ -0,0 +1,457 @@
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// Copyright (c) 2016 Jeremy Rubin
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// Distributed under the MIT software license, see the accompanying
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// file COPYING or http://www.opensource.org/licenses/mit-license.php.
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#ifndef _BITCOIN_CUCKOOCACHE_H_
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#define _BITCOIN_CUCKOOCACHE_H_
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#include <array>
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#include <algorithm>
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#include <atomic>
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#include <cstring>
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#include <cmath>
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#include <memory>
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#include <vector>
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/** namespace CuckooCache provides high performance cache primitives
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*
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* Summary:
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*
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* 1) bit_packed_atomic_flags is bit-packed atomic flags for garbage collection
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*
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* 2) cache is a cache which is performant in memory usage and lookup speed. It
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* is lockfree for erase operations. Elements are lazily erased on the next
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* insert.
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*/
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namespace CuckooCache
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{
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/** bit_packed_atomic_flags implements a container for garbage collection flags
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* that is only thread unsafe on calls to setup. This class bit-packs collection
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* flags for memory efficiency.
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*
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* All operations are std::memory_order_relaxed so external mechanisms must
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* ensure that writes and reads are properly synchronized.
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*
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* On setup(n), all bits up to n are marked as collected.
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*
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* Under the hood, because it is an 8-bit type, it makes sense to use a multiple
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* of 8 for setup, but it will be safe if that is not the case as well.
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*
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*/
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class bit_packed_atomic_flags
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{
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std::unique_ptr<std::atomic<uint8_t>[]> mem;
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public:
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/** No default constructor as there must be some size */
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bit_packed_atomic_flags() = delete;
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/**
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* bit_packed_atomic_flags constructor creates memory to sufficiently
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* keep track of garbage collection information for size entries.
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*
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* @param size the number of elements to allocate space for
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*
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* @post bit_set, bit_unset, and bit_is_set function properly forall x. x <
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* size
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* @post All calls to bit_is_set (without subsequent bit_unset) will return
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* true.
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*/
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bit_packed_atomic_flags(uint32_t size)
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{
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// pad out the size if needed
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size = (size + 7) / 8;
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mem.reset(new std::atomic<uint8_t>[size]);
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for (uint32_t i = 0; i < size; ++i)
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mem[i].store(0xFF);
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};
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/** setup marks all entries and ensures that bit_packed_atomic_flags can store
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* at least size entries
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*
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* @param b the number of elements to allocate space for
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* @post bit_set, bit_unset, and bit_is_set function properly forall x. x <
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* b
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* @post All calls to bit_is_set (without subsequent bit_unset) will return
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* true.
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*/
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inline void setup(uint32_t b)
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{
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bit_packed_atomic_flags d(b);
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std::swap(mem, d.mem);
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}
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/** bit_set sets an entry as discardable.
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*
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* @param s the index of the entry to bit_set.
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* @post immediately subsequent call (assuming proper external memory
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* ordering) to bit_is_set(s) == true.
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*
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*/
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inline void bit_set(uint32_t s)
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{
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mem[s >> 3].fetch_or(1 << (s & 7), std::memory_order_relaxed);
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}
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/** bit_unset marks an entry as something that should not be overwritten
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*
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* @param s the index of the entry to bit_unset.
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* @post immediately subsequent call (assuming proper external memory
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* ordering) to bit_is_set(s) == false.
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*/
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inline void bit_unset(uint32_t s)
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{
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mem[s >> 3].fetch_and(~(1 << (s & 7)), std::memory_order_relaxed);
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}
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/** bit_is_set queries the table for discardability at s
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*
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* @param s the index of the entry to read.
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* @returns if the bit at index s was set.
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* */
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inline bool bit_is_set(uint32_t s) const
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{
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return (1 << (s & 7)) & mem[s >> 3].load(std::memory_order_relaxed);
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}
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};
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/** cache implements a cache with properties similar to a cuckoo-set
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*
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* The cache is able to hold up to (~(uint32_t)0) - 1 elements.
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*
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* Read Operations:
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* - contains(*, false)
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*
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* Read+Erase Operations:
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* - contains(*, true)
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*
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* Erase Operations:
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* - allow_erase()
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*
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* Write Operations:
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* - setup()
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* - setup_bytes()
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* - insert()
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* - please_keep()
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*
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* Synchronization Free Operations:
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* - invalid()
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* - compute_hashes()
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*
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* User Must Guarantee:
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*
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* 1) Write Requires synchronized access (e.g., a lock)
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* 2) Read Requires no concurrent Write, synchronized with the last insert.
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* 3) Erase requires no concurrent Write, synchronized with last insert.
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* 4) An Erase caller must release all memory before allowing a new Writer.
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*
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*
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* Note on function names:
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* - The name "allow_erase" is used because the real discard happens later.
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* - The name "please_keep" is used because elements may be erased anyways on insert.
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*
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* @tparam Element should be a movable and copyable type
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* @tparam Hash should be a function/callable which takes a template parameter
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* hash_select and an Element and extracts a hash from it. Should return
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* high-entropy hashes for `Hash h; h<0>(e) ... h<7>(e)`.
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*/
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template <typename Element, typename Hash>
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class cache
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{
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private:
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/** table stores all the elements */
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std::vector<Element> table;
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/** size stores the total available slots in the hash table */
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uint32_t size;
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/** The bit_packed_atomic_flags array is marked mutable because we want
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* garbage collection to be allowed to occur from const methods */
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mutable bit_packed_atomic_flags collection_flags;
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/** epoch_flags tracks how recently an element was inserted into
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* the cache. true denotes recent, false denotes not-recent. See insert()
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* method for full semantics.
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*/
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mutable std::vector<bool> epoch_flags;
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/** epoch_heuristic_counter is used to determine when a epoch might be aged
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* & an expensive scan should be done. epoch_heuristic_counter is
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* decremented on insert and reset to the new number of inserts which would
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* cause the epoch to reach epoch_size when it reaches zero.
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*/
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uint32_t epoch_heuristic_counter;
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/** epoch_size is set to be the number of elements supposed to be in a
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* epoch. When the number of non-erased elements in a epoch
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* exceeds epoch_size, a new epoch should be started and all
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* current entries demoted. epoch_size is set to be 45% of size because
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* we want to keep load around 90%, and we support 3 epochs at once --
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* one "dead" which has been erased, one "dying" which has been marked to be
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* erased next, and one "living" which new inserts add to.
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*/
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uint32_t epoch_size;
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/** hash_mask should be set to appropriately mask out a hash such that every
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* masked hash is [0,size), eg, if floor(log2(size)) == 20, then hash_mask
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* should be (1<<20)-1
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*/
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uint32_t hash_mask;
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/** depth_limit determines how many elements insert should try to replace.
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* Should be set to log2(n)*/
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uint8_t depth_limit;
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/** hash_function is a const instance of the hash function. It cannot be
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* static or initialized at call time as it may have internal state (such as
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* a nonce).
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* */
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const Hash hash_function;
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/** compute_hashes is convenience for not having to write out this
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* expression everywhere we use the hash values of an Element.
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*
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* @param e the element whose hashes will be returned
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* @returns std::array<uint32_t, 8> of deterministic hashes derived from e
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*/
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inline std::array<uint32_t, 8> compute_hashes(const Element& e) const
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{
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return {{hash_function.template operator()<0>(e) & hash_mask,
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hash_function.template operator()<1>(e) & hash_mask,
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hash_function.template operator()<2>(e) & hash_mask,
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hash_function.template operator()<3>(e) & hash_mask,
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hash_function.template operator()<4>(e) & hash_mask,
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hash_function.template operator()<5>(e) & hash_mask,
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hash_function.template operator()<6>(e) & hash_mask,
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hash_function.template operator()<7>(e) & hash_mask}};
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}
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/* end
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* @returns a constexpr index that can never be inserted to */
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constexpr uint32_t invalid() const
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{
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return ~(uint32_t)0;
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}
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/** allow_erase marks the element at index n as discardable. Threadsafe
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* without any concurrent insert.
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* @param n the index to allow erasure of
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*/
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inline void allow_erase(uint32_t n) const
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{
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collection_flags.bit_set(n);
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}
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/** please_keep marks the element at index n as an entry that should be kept.
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* Threadsafe without any concurrent insert.
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* @param n the index to prioritize keeping
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*/
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inline void please_keep(uint32_t n) const
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{
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collection_flags.bit_unset(n);
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}
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/** epoch_check handles the changing of epochs for elements stored in the
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* cache. epoch_check should be run before every insert.
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*
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* First, epoch_check decrements and checks the cheap heuristic, and then does
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* a more expensive scan if the cheap heuristic runs out. If the expensive
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* scan suceeds, the epochs are aged and old elements are allow_erased. The
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* cheap heuristic is reset to retrigger after the worst case growth of the
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* current epoch's elements would exceed the epoch_size.
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*/
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void epoch_check()
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{
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if (epoch_heuristic_counter != 0) {
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--epoch_heuristic_counter;
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return;
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}
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// count the number of elements from the latest epoch which
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// have not been erased.
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uint32_t epoch_unused_count = 0;
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for (uint32_t i = 0; i < size; ++i)
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epoch_unused_count += epoch_flags[i] &&
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!collection_flags.bit_is_set(i);
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// If there are more non-deleted entries in the current epoch than the
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// epoch size, then allow_erase on all elements in the old epoch (marked
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// false) and move all elements in the current epoch to the old epoch
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// but do not call allow_erase on their indices.
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if (epoch_unused_count >= epoch_size) {
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for (uint32_t i = 0; i < size; ++i)
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if (epoch_flags[i])
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epoch_flags[i] = false;
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else
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allow_erase(i);
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epoch_heuristic_counter = epoch_size;
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} else
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// reset the epoch_heuristic_counter to next do a scan when worst
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// case behavior (no intermittent erases) would exceed epoch size,
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// with a reasonable minimum scan size.
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// Ordinarily, we would have to sanity check std::min(epoch_size,
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// epoch_unused_count), but we already know that `epoch_unused_count
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// < epoch_size` in this branch
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epoch_heuristic_counter = std::max(1u, std::max(epoch_size / 16,
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epoch_size - epoch_unused_count));
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}
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public:
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/** You must always construct a cache with some elements via a subsequent
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* call to setup or setup_bytes, otherwise operations may segfault.
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*/
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cache() : table(), size(), collection_flags(0), epoch_flags(),
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epoch_heuristic_counter(), epoch_size(), depth_limit(0), hash_function()
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{
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}
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/** setup initializes the container to store no more than new_size
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* elements. setup rounds down to a power of two size.
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*
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* setup should only be called once.
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*
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* @param new_size the desired number of elements to store
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* @returns the maximum number of elements storable
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**/
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uint32_t setup(uint32_t new_size)
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{
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// depth_limit must be at least one otherwise errors can occur.
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depth_limit = static_cast<uint8_t>(std::log2(static_cast<float>(std::max((uint32_t)2, new_size))));
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size = 1 << depth_limit;
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hash_mask = size-1;
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table.resize(size);
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collection_flags.setup(size);
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epoch_flags.resize(size);
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// Set to 45% as described above
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epoch_size = std::max((uint32_t)1, (45 * size) / 100);
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// Initially set to wait for a whole epoch
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epoch_heuristic_counter = epoch_size;
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return size;
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}
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/** setup_bytes is a convenience function which accounts for internal memory
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* usage when deciding how many elements to store. It isn't perfect because
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* it doesn't account for any overhead (struct size, MallocUsage, collection
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* and epoch flags). This was done to simplify selecting a power of two
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* size. In the expected use case, an extra two bits per entry should be
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* negligible compared to the size of the elements.
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*
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* @param bytes the approximate number of bytes to use for this data
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* structure.
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* @returns the maximum number of elements storable (see setup()
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* documentation for more detail)
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*/
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uint32_t setup_bytes(size_t bytes)
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{
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return setup(bytes/sizeof(Element));
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}
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/** insert loops at most depth_limit times trying to insert a hash
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* at various locations in the table via a variant of the Cuckoo Algorithm
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* with eight hash locations.
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*
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* It drops the last tried element if it runs out of depth before
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* encountering an open slot.
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*
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* Thus
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*
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* insert(x);
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* return contains(x, false);
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*
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* is not guaranteed to return true.
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*
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* @param e the element to insert
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* @post one of the following: All previously inserted elements and e are
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* now in the table, one previously inserted element is evicted from the
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* table, the entry attempted to be inserted is evicted.
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*
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*/
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inline void insert(Element e)
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{
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epoch_check();
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uint32_t last_loc = invalid();
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bool last_epoch = true;
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std::array<uint32_t, 8> locs = compute_hashes(e);
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// Make sure we have not already inserted this element
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// If we have, make sure that it does not get deleted
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for (uint32_t loc : locs)
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if (table[loc] == e) {
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please_keep(loc);
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epoch_flags[loc] = last_epoch;
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return;
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}
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for (uint8_t depth = 0; depth < depth_limit; ++depth) {
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// First try to insert to an empty slot, if one exists
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for (uint32_t loc : locs) {
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if (!collection_flags.bit_is_set(loc))
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continue;
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table[loc] = std::move(e);
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please_keep(loc);
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epoch_flags[loc] = last_epoch;
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return;
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}
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/** Swap with the element at the location that was
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* not the last one looked at. Example:
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*
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* 1) On first iteration, last_loc == invalid(), find returns last, so
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* last_loc defaults to locs[0].
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* 2) On further iterations, where last_loc == locs[k], last_loc will
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* go to locs[k+1 % 8], i.e., next of the 8 indicies wrapping around
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* to 0 if needed.
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*
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* This prevents moving the element we just put in.
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*
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* The swap is not a move -- we must switch onto the evicted element
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* for the next iteration.
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*/
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last_loc = locs[(1 + (std::find(locs.begin(), locs.end(), last_loc) - locs.begin())) & 7];
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std::swap(table[last_loc], e);
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// Can't std::swap a std::vector<bool>::reference and a bool&.
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bool epoch = last_epoch;
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last_epoch = epoch_flags[last_loc];
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epoch_flags[last_loc] = epoch;
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// Recompute the locs -- unfortunately happens one too many times!
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locs = compute_hashes(e);
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}
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}
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/* contains iterates through the hash locations for a given element
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* and checks to see if it is present.
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*
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* contains does not check garbage collected state (in other words,
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* garbage is only collected when the space is needed), so:
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*
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* insert(x);
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* if (contains(x, true))
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* return contains(x, false);
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* else
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* return true;
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*
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* executed on a single thread will always return true!
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*
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* This is a great property for re-org performance for example.
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*
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* contains returns a bool set true if the element was found.
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*
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* @param e the element to check
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* @param erase
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*
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* @post if erase is true and the element is found, then the garbage collect
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* flag is set
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* @returns true if the element is found, false otherwise
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*/
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inline bool contains(const Element& e, const bool erase) const
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{
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std::array<uint32_t, 8> locs = compute_hashes(e);
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for (uint32_t loc : locs)
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if (table[loc] == e) {
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if (erase)
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allow_erase(loc);
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return true;
|
||||
}
|
||||
return false;
|
||||
}
|
||||
};
|
||||
} // namespace CuckooCache
|
||||
|
||||
#endif
|
@ -1234,6 +1234,8 @@ bool AppInitMain(boost::thread_group& threadGroup, CScheduler& scheduler)
|
||||
LogPrintf("Using config file %s\n", GetConfigFile(GetArg("-conf", BITCOIN_CONF_FILENAME)).string());
|
||||
LogPrintf("Using at most %i connections (%i file descriptors available)\n", nMaxConnections, nFD);
|
||||
|
||||
InitSignatureCache();
|
||||
|
||||
LogPrintf("Using %u threads for script verification\n", nScriptCheckThreads);
|
||||
if (nScriptCheckThreads) {
|
||||
for (int i=0; i<nScriptCheckThreads-1; i++)
|
||||
|
@ -11,20 +11,29 @@
|
||||
#include "uint256.h"
|
||||
#include "util.h"
|
||||
|
||||
#include "cuckoocache.h"
|
||||
#include <boost/thread.hpp>
|
||||
#include <boost/unordered_set.hpp>
|
||||
|
||||
namespace {
|
||||
|
||||
/**
|
||||
* We're hashing a nonce into the entries themselves, so we don't need extra
|
||||
* blinding in the set hash computation.
|
||||
*
|
||||
* This may exhibit platform endian dependent behavior but because these are
|
||||
* nonced hashes (random) and this state is only ever used locally it is safe.
|
||||
* All that matters is local consistency.
|
||||
*/
|
||||
class CSignatureCacheHasher
|
||||
class SignatureCacheHasher
|
||||
{
|
||||
public:
|
||||
size_t operator()(const uint256& key) const {
|
||||
return key.GetCheapHash();
|
||||
template <uint8_t hash_select>
|
||||
uint32_t operator()(const uint256& key) const
|
||||
{
|
||||
static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
|
||||
uint32_t u;
|
||||
std::memcpy(&u, key.begin()+4*hash_select, 4);
|
||||
return u;
|
||||
}
|
||||
};
|
||||
|
||||
@ -38,11 +47,10 @@ class CSignatureCache
|
||||
private:
|
||||
//! Entries are SHA256(nonce || signature hash || public key || signature):
|
||||
uint256 nonce;
|
||||
typedef boost::unordered_set<uint256, CSignatureCacheHasher> map_type;
|
||||
typedef CuckooCache::cache<uint256, SignatureCacheHasher> map_type;
|
||||
map_type setValid;
|
||||
boost::shared_mutex cs_sigcache;
|
||||
|
||||
|
||||
public:
|
||||
CSignatureCache()
|
||||
{
|
||||
@ -56,58 +64,51 @@ public:
|
||||
}
|
||||
|
||||
bool
|
||||
Get(const uint256& entry)
|
||||
Get(const uint256& entry, const bool erase)
|
||||
{
|
||||
boost::shared_lock<boost::shared_mutex> lock(cs_sigcache);
|
||||
return setValid.count(entry);
|
||||
return setValid.contains(entry, erase);
|
||||
}
|
||||
|
||||
void Erase(const uint256& entry)
|
||||
void Set(uint256& entry)
|
||||
{
|
||||
boost::unique_lock<boost::shared_mutex> lock(cs_sigcache);
|
||||
setValid.erase(entry);
|
||||
}
|
||||
|
||||
void Set(const uint256& entry)
|
||||
{
|
||||
size_t nMaxCacheSize = GetArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
|
||||
if (nMaxCacheSize <= 0) return;
|
||||
|
||||
boost::unique_lock<boost::shared_mutex> lock(cs_sigcache);
|
||||
while (memusage::DynamicUsage(setValid) > nMaxCacheSize)
|
||||
{
|
||||
map_type::size_type s = GetRand(setValid.bucket_count());
|
||||
map_type::local_iterator it = setValid.begin(s);
|
||||
if (it != setValid.end(s)) {
|
||||
setValid.erase(*it);
|
||||
}
|
||||
}
|
||||
|
||||
setValid.insert(entry);
|
||||
}
|
||||
uint32_t setup_bytes(size_t n)
|
||||
{
|
||||
return setValid.setup_bytes(n);
|
||||
}
|
||||
};
|
||||
|
||||
/* In previous versions of this code, signatureCache was a local static variable
|
||||
* in CachingTransactionSignatureChecker::VerifySignature. We initialize
|
||||
* signatureCache outside of VerifySignature to avoid the atomic operation per
|
||||
* call overhead associated with local static variables even though
|
||||
* signatureCache could be made local to VerifySignature.
|
||||
*/
|
||||
static CSignatureCache signatureCache;
|
||||
}
|
||||
|
||||
// To be called once in AppInit2/TestingSetup to initialize the signatureCache
|
||||
void InitSignatureCache()
|
||||
{
|
||||
size_t nMaxCacheSize = GetArg("-maxsigcachesize", DEFAULT_MAX_SIG_CACHE_SIZE) * ((size_t) 1 << 20);
|
||||
if (nMaxCacheSize <= 0) return;
|
||||
size_t nElems = signatureCache.setup_bytes(nMaxCacheSize);
|
||||
LogPrintf("Using %zu MiB out of %zu requested for signature cache, able to store %zu elements\n",
|
||||
(nElems*sizeof(uint256)) >>20, nMaxCacheSize>>20, nElems);
|
||||
}
|
||||
|
||||
bool CachingTransactionSignatureChecker::VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& pubkey, const uint256& sighash) const
|
||||
{
|
||||
static CSignatureCache signatureCache;
|
||||
|
||||
uint256 entry;
|
||||
signatureCache.ComputeEntry(entry, sighash, vchSig, pubkey);
|
||||
|
||||
if (signatureCache.Get(entry)) {
|
||||
if (!store) {
|
||||
signatureCache.Erase(entry);
|
||||
}
|
||||
if (signatureCache.Get(entry, !store))
|
||||
return true;
|
||||
}
|
||||
|
||||
if (!TransactionSignatureChecker::VerifySignature(vchSig, pubkey, sighash))
|
||||
return false;
|
||||
|
||||
if (store) {
|
||||
if (store)
|
||||
signatureCache.Set(entry);
|
||||
}
|
||||
return true;
|
||||
}
|
||||
|
@ -10,9 +10,10 @@
|
||||
|
||||
#include <vector>
|
||||
|
||||
// DoS prevention: limit cache size to less than 40MB (over 500000
|
||||
// entries on 64-bit systems).
|
||||
static const unsigned int DEFAULT_MAX_SIG_CACHE_SIZE = 40;
|
||||
// DoS prevention: limit cache size to 32MB (over 1000000 entries on 64-bit
|
||||
// systems). Due to how we count cache size, actual memory usage is slightly
|
||||
// more (~32.25 MB)
|
||||
static const unsigned int DEFAULT_MAX_SIG_CACHE_SIZE = 32;
|
||||
|
||||
class CPubKey;
|
||||
|
||||
@ -27,4 +28,6 @@ public:
|
||||
bool VerifySignature(const std::vector<unsigned char>& vchSig, const CPubKey& vchPubKey, const uint256& sighash) const;
|
||||
};
|
||||
|
||||
void InitSignatureCache();
|
||||
|
||||
#endif // BITCOIN_SCRIPT_SIGCACHE_H
|
||||
|
394
src/test/cuckoocache_tests.cpp
Normal file
394
src/test/cuckoocache_tests.cpp
Normal file
@ -0,0 +1,394 @@
|
||||
// Copyright (c) 2012-2016 The Bitcoin Core developers
|
||||
// Distributed under the MIT software license, see the accompanying
|
||||
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
|
||||
#include <boost/test/unit_test.hpp>
|
||||
#include "cuckoocache.h"
|
||||
#include "test/test_dash.h"
|
||||
#include "random.h"
|
||||
#include <thread>
|
||||
#include <boost/thread.hpp>
|
||||
|
||||
|
||||
/** Test Suite for CuckooCache
|
||||
*
|
||||
* 1) All tests should have a deterministic result (using insecure rand
|
||||
* with deterministic seeds)
|
||||
* 2) Some test methods are templated to allow for easier testing
|
||||
* against new versions / comparing
|
||||
* 3) Results should be treated as a regression test, ie, did the behavior
|
||||
* change significantly from what was expected. This can be OK, depending on
|
||||
* the nature of the change, but requires updating the tests to reflect the new
|
||||
* expected behavior. For example improving the hit rate may cause some tests
|
||||
* using BOOST_CHECK_CLOSE to fail.
|
||||
*
|
||||
*/
|
||||
FastRandomContext insecure_rand(true);
|
||||
|
||||
BOOST_AUTO_TEST_SUITE(cuckoocache_tests);
|
||||
|
||||
|
||||
/** insecure_GetRandHash fills in a uint256 from insecure_rand
|
||||
*/
|
||||
void insecure_GetRandHash(uint256& t)
|
||||
{
|
||||
uint32_t* ptr = (uint32_t*)t.begin();
|
||||
for (uint8_t j = 0; j < 8; ++j)
|
||||
*(ptr++) = insecure_rand.rand32();
|
||||
}
|
||||
|
||||
/** Definition copied from /src/script/sigcache.cpp
|
||||
*/
|
||||
class uint256Hasher
|
||||
{
|
||||
public:
|
||||
template <uint8_t hash_select>
|
||||
uint32_t operator()(const uint256& key) const
|
||||
{
|
||||
static_assert(hash_select <8, "SignatureCacheHasher only has 8 hashes available.");
|
||||
uint32_t u;
|
||||
std::memcpy(&u, key.begin() + 4 * hash_select, 4);
|
||||
return u;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
/* Test that no values not inserted into the cache are read out of it.
|
||||
*
|
||||
* There are no repeats in the first 200000 insecure_GetRandHash calls
|
||||
*/
|
||||
BOOST_AUTO_TEST_CASE(test_cuckoocache_no_fakes)
|
||||
{
|
||||
insecure_rand = FastRandomContext(true);
|
||||
CuckooCache::cache<uint256, uint256Hasher> cc{};
|
||||
cc.setup_bytes(32 << 20);
|
||||
uint256 v;
|
||||
for (int x = 0; x < 100000; ++x) {
|
||||
insecure_GetRandHash(v);
|
||||
cc.insert(v);
|
||||
}
|
||||
for (int x = 0; x < 100000; ++x) {
|
||||
insecure_GetRandHash(v);
|
||||
BOOST_CHECK(!cc.contains(v, false));
|
||||
}
|
||||
};
|
||||
|
||||
/** This helper returns the hit rate when megabytes*load worth of entries are
|
||||
* inserted into a megabytes sized cache
|
||||
*/
|
||||
template <typename Cache>
|
||||
double test_cache(size_t megabytes, double load)
|
||||
{
|
||||
insecure_rand = FastRandomContext(true);
|
||||
std::vector<uint256> hashes;
|
||||
Cache set{};
|
||||
size_t bytes = megabytes * (1 << 20);
|
||||
set.setup_bytes(bytes);
|
||||
uint32_t n_insert = static_cast<uint32_t>(load * (bytes / sizeof(uint256)));
|
||||
hashes.resize(n_insert);
|
||||
for (uint32_t i = 0; i < n_insert; ++i) {
|
||||
uint32_t* ptr = (uint32_t*)hashes[i].begin();
|
||||
for (uint8_t j = 0; j < 8; ++j)
|
||||
*(ptr++) = insecure_rand.rand32();
|
||||
}
|
||||
/** We make a copy of the hashes because future optimizations of the
|
||||
* cuckoocache may overwrite the inserted element, so the test is
|
||||
* "future proofed".
|
||||
*/
|
||||
std::vector<uint256> hashes_insert_copy = hashes;
|
||||
/** Do the insert */
|
||||
for (uint256& h : hashes_insert_copy)
|
||||
set.insert(h);
|
||||
/** Count the hits */
|
||||
uint32_t count = 0;
|
||||
for (uint256& h : hashes)
|
||||
count += set.contains(h, false);
|
||||
double hit_rate = ((double)count) / ((double)n_insert);
|
||||
return hit_rate;
|
||||
}
|
||||
|
||||
/** The normalized hit rate for a given load.
|
||||
*
|
||||
* The semantics are a little confusing, so please see the below
|
||||
* explanation.
|
||||
*
|
||||
* Examples:
|
||||
*
|
||||
* 1) at load 0.5, we expect a perfect hit rate, so we multiply by
|
||||
* 1.0
|
||||
* 2) at load 2.0, we expect to see half the entries, so a perfect hit rate
|
||||
* would be 0.5. Therefore, if we see a hit rate of 0.4, 0.4*2.0 = 0.8 is the
|
||||
* normalized hit rate.
|
||||
*
|
||||
* This is basically the right semantics, but has a bit of a glitch depending on
|
||||
* how you measure around load 1.0 as after load 1.0 your normalized hit rate
|
||||
* becomes effectively perfect, ignoring freshness.
|
||||
*/
|
||||
double normalize_hit_rate(double hits, double load)
|
||||
{
|
||||
return hits * std::max(load, 1.0);
|
||||
}
|
||||
|
||||
/** Check the hit rate on loads ranging from 0.1 to 2.0 */
|
||||
BOOST_AUTO_TEST_CASE(cuckoocache_hit_rate_ok)
|
||||
{
|
||||
/** Arbitrarily selected Hit Rate threshold that happens to work for this test
|
||||
* as a lower bound on performance.
|
||||
*/
|
||||
double HitRateThresh = 0.98;
|
||||
size_t megabytes = 32;
|
||||
for (double load = 0.1; load < 2; load *= 2) {
|
||||
double hits = test_cache<CuckooCache::cache<uint256, uint256Hasher>>(megabytes, load);
|
||||
BOOST_CHECK(normalize_hit_rate(hits, load) > HitRateThresh);
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
/** This helper checks that erased elements are preferentially inserted onto and
|
||||
* that the hit rate of "fresher" keys is reasonable*/
|
||||
template <typename Cache>
|
||||
void test_cache_erase(size_t megabytes)
|
||||
{
|
||||
double load = 1;
|
||||
insecure_rand = FastRandomContext(true);
|
||||
std::vector<uint256> hashes;
|
||||
Cache set{};
|
||||
size_t bytes = megabytes * (1 << 20);
|
||||
set.setup_bytes(bytes);
|
||||
uint32_t n_insert = static_cast<uint32_t>(load * (bytes / sizeof(uint256)));
|
||||
hashes.resize(n_insert);
|
||||
for (uint32_t i = 0; i < n_insert; ++i) {
|
||||
uint32_t* ptr = (uint32_t*)hashes[i].begin();
|
||||
for (uint8_t j = 0; j < 8; ++j)
|
||||
*(ptr++) = insecure_rand.rand32();
|
||||
}
|
||||
/** We make a copy of the hashes because future optimizations of the
|
||||
* cuckoocache may overwrite the inserted element, so the test is
|
||||
* "future proofed".
|
||||
*/
|
||||
std::vector<uint256> hashes_insert_copy = hashes;
|
||||
|
||||
/** Insert the first half */
|
||||
for (uint32_t i = 0; i < (n_insert / 2); ++i)
|
||||
set.insert(hashes_insert_copy[i]);
|
||||
/** Erase the first quarter */
|
||||
for (uint32_t i = 0; i < (n_insert / 4); ++i)
|
||||
set.contains(hashes[i], true);
|
||||
/** Insert the second half */
|
||||
for (uint32_t i = (n_insert / 2); i < n_insert; ++i)
|
||||
set.insert(hashes_insert_copy[i]);
|
||||
|
||||
/** elements that we marked erased but that are still there */
|
||||
size_t count_erased_but_contained = 0;
|
||||
/** elements that we did not erase but are older */
|
||||
size_t count_stale = 0;
|
||||
/** elements that were most recently inserted */
|
||||
size_t count_fresh = 0;
|
||||
|
||||
for (uint32_t i = 0; i < (n_insert / 4); ++i)
|
||||
count_erased_but_contained += set.contains(hashes[i], false);
|
||||
for (uint32_t i = (n_insert / 4); i < (n_insert / 2); ++i)
|
||||
count_stale += set.contains(hashes[i], false);
|
||||
for (uint32_t i = (n_insert / 2); i < n_insert; ++i)
|
||||
count_fresh += set.contains(hashes[i], false);
|
||||
|
||||
double hit_rate_erased_but_contained = double(count_erased_but_contained) / (double(n_insert) / 4.0);
|
||||
double hit_rate_stale = double(count_stale) / (double(n_insert) / 4.0);
|
||||
double hit_rate_fresh = double(count_fresh) / (double(n_insert) / 2.0);
|
||||
|
||||
// Check that our hit_rate_fresh is perfect
|
||||
BOOST_CHECK_EQUAL(hit_rate_fresh, 1.0);
|
||||
// Check that we have a more than 2x better hit rate on stale elements than
|
||||
// erased elements.
|
||||
BOOST_CHECK(hit_rate_stale > 2 * hit_rate_erased_but_contained);
|
||||
}
|
||||
|
||||
BOOST_AUTO_TEST_CASE(cuckoocache_erase_ok)
|
||||
{
|
||||
size_t megabytes = 32;
|
||||
test_cache_erase<CuckooCache::cache<uint256, uint256Hasher>>(megabytes);
|
||||
}
|
||||
|
||||
template <typename Cache>
|
||||
void test_cache_erase_parallel(size_t megabytes)
|
||||
{
|
||||
double load = 1;
|
||||
insecure_rand = FastRandomContext(true);
|
||||
std::vector<uint256> hashes;
|
||||
Cache set{};
|
||||
size_t bytes = megabytes * (1 << 20);
|
||||
set.setup_bytes(bytes);
|
||||
uint32_t n_insert = static_cast<uint32_t>(load * (bytes / sizeof(uint256)));
|
||||
hashes.resize(n_insert);
|
||||
for (uint32_t i = 0; i < n_insert; ++i) {
|
||||
uint32_t* ptr = (uint32_t*)hashes[i].begin();
|
||||
for (uint8_t j = 0; j < 8; ++j)
|
||||
*(ptr++) = insecure_rand.rand32();
|
||||
}
|
||||
/** We make a copy of the hashes because future optimizations of the
|
||||
* cuckoocache may overwrite the inserted element, so the test is
|
||||
* "future proofed".
|
||||
*/
|
||||
std::vector<uint256> hashes_insert_copy = hashes;
|
||||
boost::shared_mutex mtx;
|
||||
|
||||
{
|
||||
/** Grab lock to make sure we release inserts */
|
||||
boost::unique_lock<boost::shared_mutex> l(mtx);
|
||||
/** Insert the first half */
|
||||
for (uint32_t i = 0; i < (n_insert / 2); ++i)
|
||||
set.insert(hashes_insert_copy[i]);
|
||||
}
|
||||
|
||||
/** Spin up 3 threads to run contains with erase.
|
||||
*/
|
||||
std::vector<std::thread> threads;
|
||||
/** Erase the first quarter */
|
||||
for (uint32_t x = 0; x < 3; ++x)
|
||||
/** Each thread is emplaced with x copy-by-value
|
||||
*/
|
||||
threads.emplace_back([&, x] {
|
||||
boost::shared_lock<boost::shared_mutex> l(mtx);
|
||||
size_t ntodo = (n_insert/4)/3;
|
||||
size_t start = ntodo*x;
|
||||
size_t end = ntodo*(x+1);
|
||||
for (uint32_t i = start; i < end; ++i)
|
||||
set.contains(hashes[i], true);
|
||||
});
|
||||
|
||||
/** Wait for all threads to finish
|
||||
*/
|
||||
for (std::thread& t : threads)
|
||||
t.join();
|
||||
/** Grab lock to make sure we observe erases */
|
||||
boost::unique_lock<boost::shared_mutex> l(mtx);
|
||||
/** Insert the second half */
|
||||
for (uint32_t i = (n_insert / 2); i < n_insert; ++i)
|
||||
set.insert(hashes_insert_copy[i]);
|
||||
|
||||
/** elements that we marked erased but that are still there */
|
||||
size_t count_erased_but_contained = 0;
|
||||
/** elements that we did not erase but are older */
|
||||
size_t count_stale = 0;
|
||||
/** elements that were most recently inserted */
|
||||
size_t count_fresh = 0;
|
||||
|
||||
for (uint32_t i = 0; i < (n_insert / 4); ++i)
|
||||
count_erased_but_contained += set.contains(hashes[i], false);
|
||||
for (uint32_t i = (n_insert / 4); i < (n_insert / 2); ++i)
|
||||
count_stale += set.contains(hashes[i], false);
|
||||
for (uint32_t i = (n_insert / 2); i < n_insert; ++i)
|
||||
count_fresh += set.contains(hashes[i], false);
|
||||
|
||||
double hit_rate_erased_but_contained = double(count_erased_but_contained) / (double(n_insert) / 4.0);
|
||||
double hit_rate_stale = double(count_stale) / (double(n_insert) / 4.0);
|
||||
double hit_rate_fresh = double(count_fresh) / (double(n_insert) / 2.0);
|
||||
|
||||
// Check that our hit_rate_fresh is perfect
|
||||
BOOST_CHECK_EQUAL(hit_rate_fresh, 1.0);
|
||||
// Check that we have a more than 2x better hit rate on stale elements than
|
||||
// erased elements.
|
||||
BOOST_CHECK(hit_rate_stale > 2 * hit_rate_erased_but_contained);
|
||||
}
|
||||
BOOST_AUTO_TEST_CASE(cuckoocache_erase_parallel_ok)
|
||||
{
|
||||
size_t megabytes = 32;
|
||||
test_cache_erase_parallel<CuckooCache::cache<uint256, uint256Hasher>>(megabytes);
|
||||
}
|
||||
|
||||
|
||||
template <typename Cache>
|
||||
void test_cache_generations()
|
||||
{
|
||||
// This test checks that for a simulation of network activity, the fresh hit
|
||||
// rate is never below 99%, and the number of times that it is worse than
|
||||
// 99.9% are less than 1% of the time.
|
||||
double min_hit_rate = 0.99;
|
||||
double tight_hit_rate = 0.999;
|
||||
double max_rate_less_than_tight_hit_rate = 0.01;
|
||||
// A cache that meets this specification is therefore shown to have a hit
|
||||
// rate of at least tight_hit_rate * (1 - max_rate_less_than_tight_hit_rate) +
|
||||
// min_hit_rate*max_rate_less_than_tight_hit_rate = 0.999*99%+0.99*1% == 99.89%
|
||||
// hit rate with low variance.
|
||||
|
||||
// We use deterministic values, but this test has also passed on many
|
||||
// iterations with non-deterministic values, so it isn't "overfit" to the
|
||||
// specific entropy in FastRandomContext(true) and implementation of the
|
||||
// cache.
|
||||
insecure_rand = FastRandomContext(true);
|
||||
|
||||
// block_activity models a chunk of network activity. n_insert elements are
|
||||
// adde to the cache. The first and last n/4 are stored for removal later
|
||||
// and the middle n/2 are not stored. This models a network which uses half
|
||||
// the signatures of recently (since the last block) added transactions
|
||||
// immediately and never uses the other half.
|
||||
struct block_activity {
|
||||
std::vector<uint256> reads;
|
||||
block_activity(uint32_t n_insert, Cache& c) : reads()
|
||||
{
|
||||
std::vector<uint256> inserts;
|
||||
inserts.resize(n_insert);
|
||||
reads.reserve(n_insert / 2);
|
||||
for (uint32_t i = 0; i < n_insert; ++i) {
|
||||
uint32_t* ptr = (uint32_t*)inserts[i].begin();
|
||||
for (uint8_t j = 0; j < 8; ++j)
|
||||
*(ptr++) = insecure_rand.rand32();
|
||||
}
|
||||
for (uint32_t i = 0; i < n_insert / 4; ++i)
|
||||
reads.push_back(inserts[i]);
|
||||
for (uint32_t i = n_insert - (n_insert / 4); i < n_insert; ++i)
|
||||
reads.push_back(inserts[i]);
|
||||
for (auto h : inserts)
|
||||
c.insert(h);
|
||||
}
|
||||
};
|
||||
|
||||
const uint32_t BLOCK_SIZE = 10000;
|
||||
// We expect window size 60 to perform reasonably given that each epoch
|
||||
// stores 45% of the cache size (~472k).
|
||||
const uint32_t WINDOW_SIZE = 60;
|
||||
const uint32_t POP_AMOUNT = (BLOCK_SIZE / WINDOW_SIZE) / 2;
|
||||
const double load = 10;
|
||||
const size_t megabytes = 32;
|
||||
const size_t bytes = megabytes * (1 << 20);
|
||||
const uint32_t n_insert = static_cast<uint32_t>(load * (bytes / sizeof(uint256)));
|
||||
|
||||
std::vector<block_activity> hashes;
|
||||
Cache set{};
|
||||
set.setup_bytes(bytes);
|
||||
hashes.reserve(n_insert / BLOCK_SIZE);
|
||||
std::deque<block_activity> last_few;
|
||||
uint32_t out_of_tight_tolerance = 0;
|
||||
uint32_t total = n_insert / BLOCK_SIZE;
|
||||
// we use the deque last_few to model a sliding window of blocks. at each
|
||||
// step, each of the last WINDOW_SIZE block_activities checks the cache for
|
||||
// POP_AMOUNT of the hashes that they inserted, and marks these erased.
|
||||
for (uint32_t i = 0; i < total; ++i) {
|
||||
if (last_few.size() == WINDOW_SIZE)
|
||||
last_few.pop_front();
|
||||
last_few.emplace_back(BLOCK_SIZE, set);
|
||||
uint32_t count = 0;
|
||||
for (auto& act : last_few)
|
||||
for (uint32_t k = 0; k < POP_AMOUNT; ++k) {
|
||||
count += set.contains(act.reads.back(), true);
|
||||
act.reads.pop_back();
|
||||
}
|
||||
// We use last_few.size() rather than WINDOW_SIZE for the correct
|
||||
// behavior on the first WINDOW_SIZE iterations where the deque is not
|
||||
// full yet.
|
||||
double hit = (double(count)) / (last_few.size() * POP_AMOUNT);
|
||||
// Loose Check that hit rate is above min_hit_rate
|
||||
BOOST_CHECK(hit > min_hit_rate);
|
||||
// Tighter check, count number of times we are less than tight_hit_rate
|
||||
// (and implicityly, greater than min_hit_rate)
|
||||
out_of_tight_tolerance += hit < tight_hit_rate;
|
||||
}
|
||||
// Check that being out of tolerance happens less than
|
||||
// max_rate_less_than_tight_hit_rate of the time
|
||||
BOOST_CHECK(double(out_of_tight_tolerance) / double(total) < max_rate_less_than_tight_hit_rate);
|
||||
}
|
||||
BOOST_AUTO_TEST_CASE(cuckoocache_generations)
|
||||
{
|
||||
test_cache_generations<CuckooCache::cache<uint256, uint256Hasher>>();
|
||||
}
|
||||
|
||||
BOOST_AUTO_TEST_SUITE_END();
|
@ -20,6 +20,7 @@
|
||||
#include "ui_interface.h"
|
||||
#include "rpc/server.h"
|
||||
#include "rpc/register.h"
|
||||
#include "script/sigcache.h"
|
||||
|
||||
#include "test/testutil.h"
|
||||
|
||||
@ -40,6 +41,7 @@ BasicTestingSetup::BasicTestingSetup(const std::string& chainName)
|
||||
ECC_Start();
|
||||
SetupEnvironment();
|
||||
SetupNetworking();
|
||||
InitSignatureCache();
|
||||
fPrintToDebugLog = false; // don't want to write to debug.log file
|
||||
fCheckBlockIndex = true;
|
||||
SelectParams(chainName);
|
||||
|
Loading…
Reference in New Issue
Block a user