A locality-improving dynamic memory allocator

Abstract

In general-purpose applications, most data is dynamically allocated. The memory manager therefore plays a crucial role in application performance by determining the spatial locality of heap objects. Previous general-purpose allocators have focused on reducing fragmentation, while most locality-improving allocators have either focused on improving the locality of the allocator (not the application), or required programmer hints or profiling to guide object placement. We present a high-performance memory allocator called Vam that transparently improves both cache-level and page-level locality of the application while achieving low fragmentation. Over a range of large-footprint benchmarks, Vam improves application performance by an average of 4%-8% versus the Lea (Linux) and FreeBSD allocators. When memory is scarce, Vam improves application performance by up to 2X compared to the FreeBSD allocator, and by over 10X compared to the Lea allocator.