NextGen-Malloc: Giving Memory Allocator Its Own Room in the House

Abstract

Memory allocation and management have a significant impact on performance and energy of modern applications. We observe that performance can vary by as much as 72% in some applications based on which memory allocator is used. Many current allocators are multi-threaded to support concurrent allocation requests from different threads. However, such multi-threading comes at the cost of maintaining complex metadata that is tightly coupled and intertwined with user data. When memory management functions and other user programs run on the same core, the metadata used by management functions may pollute the processor caches and other resources. In this paper, we make a case for offloading memory allocation (and other similar management functions) from main processing cores to other processing units to boost performance, reduce energy consumption, and customize services to specific applications or application domains. To offload these multi-threaded fine-granularity functions, we propose to decouple the metadata of these functions from the rest of application data to reduce the overhead of inter-thread metadata synchronization. We draw attention to the following key questions to realize this opportunity: (a) What are the tradeoffs and challenges in offloading memory allocation to a dedicated core? (b) Should we use general-purpose cores or special-purpose cores for executing critical system management functions? (c) Can this methodology apply to heterogeneous systems (e.g., with GPUs, accelerators) and other service functions as well?