Allocating Memory in a Lock-Free Manner

Abstract

Abstract. The potential of multiprocessor systems is often not fully realized by their system services. Certain synchronization methods, such as lock-based ones, may limit the parallelism. It is significant to see the impact of wait/lock-free synchronization design in key services for multiprocessor systems, such as the memory allocation service. Efficient, scalable memory allocators for multithreaded applications on multiprocessors is a significant goal of recent research projects.We propose a lock-free memory allocator, to enhance the parallelism in the system. Its architecture is inspired by Hoard, a successful concurrent memory allocator, with a modular, scalable design that preserves scalability and helps avoiding false-sharing and heap blowup. Within our effort on designing appropriate lock-free algorithms to construct this system, we propose a new non-blocking data structure called flat-sets, supporting conventional "internal" operations as well as "inter-object" operations, for moving items between flat-sets.We implemented the memory allocator in a set of multiprocessor systems (UMA Sun Enterprise 450 and ccNUMA Origin 3800) and studied its behaviour. The results show that the good properties of Hoard w.r.t. false-sharing and heap-blowup are preserved, while the scalability properties are enhanced even further with the help of lock-free synchronization.

Progress guarantee for parallel programs via bounded lock-freedom

“…This extra condition is not needed in case the bound on the time to make progress is a constant that does not depend on the input. 7 The last condition ensures that the program behaves properly.…”

“…Many example appear in [13] Related to the discussion on memory management above, one should note that lock-free supporting algorithms for manually allocating and deleting objects exist and high-performance implementations have been written by Michael [20] and Gidenstam et al [7].…”

Lock‐Free Concurrent Data Structures

“…In [26,27] a data structure called flat-sets, was introduced and used as a building block in the concurrent memory allocation service. This is a bag-like structure that supports lock-free insertion and removal of items as well as an "inter-object" operation, for moving an item from one flat-set to another in a lock-free and linearizable manner, thus offering the possibility of combining data structures.…”

Μεθοδολογίες Αυτοματοποιημένης Εξερεύνησης Και Σύνθεσης Επαναδιατάξιμων Συνεπεξεργαστών Υλικού

“…Such trade-offs can be efficiently utilized through customization of the allocator according to the application specific needs. Characteristic DM managers of this class are the DYNIX kernel memory allocator [85], the allocator proposed by Vee and Hsu [37], the Hoard allocator by Berger [21] and its lock-free variants [86], [87]. …”

“…After each operation on a shared resource of the system, specialized mechanisms are triggered to validate the legality of the operation i.e. conflict detection mechanisms [89], guarding mechanisms [90] and atomic transactions [86]. Here, we consider MTh-DMM implementations based on blocking synchronization primitives, since non-blocking synchronization requires complex hardware and OS support [91] usually inappropriate for embedded solutions.…”