2021/04/30 by Vitaly Aksenov, Nikita Koval, Aksenov, Vitaly +5
Computer Science · #Data Structures and Algorithms (cs.DS) #Distributed #Distributed systems and fault tolerance #FOS: Computer and information sciences #Optimization and Search Problems #Parallel #Parallel Computing and Optimization Techniques #and Cluster Computing (cs.DC)
paper · pdf · doi:10.48550/arxiv.2104.15003
openalex publication_date 2021/04/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Concurrent data structures often require additional memory for handling synchronization issues in addition to memory for storing elements. Depending on the amount of this additional memory, implementations can be more or less memory-friendly. A memory-optimal implementation enjoys the minimal possible memory overhead, which, in practice, reduces cache misses and unnecessary memory reclamation. In this paper, we discuss the memory-optimality of non-blocking bounded queues. Essentially, we investigate the possibility of constructing an implementation that utilizes a pre-allocated array to store elements and constant memory overhead, e.g., two positioning counters for enqueue(..) and dequeue() operations. Such an implementation can be readily constructed when the ABA problem is precluded, e.g., assuming that the hardware supports LL/SC instructions or all inserted elements are distinct. However, in the general case, we show that a memory-optimal non-blocking bounded queue incurs linear overhead in the number of concurrent processes. These results not only provide helpful intuition for concurrent algorithm developers but also open a new research avenue on the memory-optimality phenomenon in concurrent data structures.