atomic bitvector

An atomic bitset/bitvector with size determined at runtime

overview

This header-only library encodes a bitvector class with size fixed at runtime. Atomic operations allow for concurrent access and modification of the bitset. Such a structure can help with coordinating parallel processing of a given fixed set of entities, and has the advantage of only requiring O(1) bit per entry.

The atomic_bv_t class is a straightforward extension of ConcurrentBitSet from Facebook's folly C++ library. It wraps the atomic type with a class that allows them to be copied, and these wrapped atomic types are then used to build a vector whose size is determined at runtime.

tests

Build the test using:

cmake -H. -Bbuild && cmake --build build -- -j4

And run it with:

n_bits=10000000
n_threads=4
time bin/test_atomicbitvector $n_bits $n_threads

In the test, $n_threads write randomly to a bitvector of $n_bits. A reporting thread runs over the bitvector, checking when all bits have been set. Parallel speedup can be confirmed by setting $n_threads to 1, 2, 3 ... up to the number of parallel processes allowed on the system.

example usage

#include <atomic_bitvector.hpp>
#include <thread>

int main(int argc, char** argv) {
    atomicbitvector::atomic_bv_t x(1000);
    size_t i = 100;
    x.test(i);  // false
    x.set(i);   // false (returns previous value)
    x.test(i);  // true
    x.reset(i); // true (returns previous value)n
    x.test(i);  // false
    return 0;
}

All operations are atomic and threadsafe.

license

Apache2