Feasibility of decoupling memory management from the execution pipeline

In conventional architectures, the central processing unit (CPU) spends a significant amount of execution time allocating and de-allocating memory. Efforts to improve memory management functions using custom allocators have led to only small improvements in performance. In this work, we test the feasibility of decoupling memory management functions from the main processing element to a separate memory management hardware. Such memory management hardware can reside on the same die as the CPU, in a memory controller or embedded within a DRAM chip. Using Simplescalar, we simulated our architecture and investigated the execution performance of various benchmarks selected from SPECInt2000, Olden and other memory intensive application suites. Hardware allocator reduced the execution time of applications by as much as 50%. In fact, the decoupled hardware results in a performance improvement even when we assume that both the hardware and software memory allocators require the same number of cycles. We attribute much of this improved performance to improved cache behavior since decoupling memory management functions reduces cache pollution caused by dynamic memory management software. We anticipate that even higher levels of performance can be achieved by using innovative hardware and software optimizations. We do not show any specific implementation for the memory management hardware. This paper only investigates the potential performance gains that can result from a hardware allocator.