Memory allocation for long-running server applications

Abstract

Prior work on dynamic memory allocation has largely neglected long-running server applications, for example, web servers and mail servers. Their requirements differ from those of one-shot applications like compilers or text editors. We investigated how to build an allocator that is not only fast and memory efficient but also scales well on SMP machines. We found that it is not sufficient to focus on reducing lock contention - higher speedups require a reduction in cache misses and bus traffic. We then designed and prototyped a new allocator, called LKmalloc, targeted for both traditional applications and server applications. LKmalloc uses several subheaps, each one with a separate set of free lists and memory arena. A thread always allocates from the same subheap but can free a block belonging to any subheap. A thread is assigned to a subheap by hashing on its thread ID. WC compared its performance with several other allocators on a server-like, simulated workload and found that it indeed scales well and is quite fast hut memory more efficiently.