Design and Code Optimization for Systems with Next-generation Racetrack Memories

With the rise of computationally expensive application domains such as machine learning, genomics, and fluids simulation, the quest for performance and energy-efficient computing has gained unprecedented momentum. The significant increase in computing and memory devices in modern systems has resulted in an unsustainable surge in energy consumption, a substantial portion of which is attributed to the memory system. The scaling of conventional memory technologies and their suitability for the next-generation system is also questionable. This has led to the emergence and rise of nonvolatile memory ( NVM ) technologies. Today, in different development stages, several NVM technologies are competing for their rapid access to the market. Racetrack memory ( RTM ) is one such nonvolatile memory technology that promises SRAM -comparable latency, reduced energy consumption, and unprecedented density compared to other technologies. However, racetrack memory ( RTM ) is sequential in nature, i.e., data in an RTM cell needs to be shifted to an access port before it can be accessed. These shift operations incur performance and energy penalties. An ideal RTM , requiring at most one shift per access, can easily outperform SRAM . However, in the worst-cast shifting scenario, RTM can be an order of magnitude slower than SRAM . This thesis presents an overview of the RTM device physics, its evolution, strengths and challenges, and its application in the memory subsystem. We develop tools that allow the programmability and modeling of RTM -based systems. For shifts minimization, we propose a set of techniques including optimal, near-optimal, and evolutionary algorithms for efficient scalar and instruction placement in RTMs . For array accesses, we explore schedule and layout transformations that eliminate the longer overhead shifts in RTMs . We present an automatic compilation framework that analyzes static control flow programs and transforms the loop traversal order and memory layout to maximize accesses to consecutive RTM locations and minimize shifts. We develop a simulation framework called RTSim that models various RTM parameters and enables accurate architectural level simulation. Finally, to demonstrate the RTM potential in non-Von-Neumann in-memory computing paradigms, we exploit its device attributes to implement logic and arithmetic operations. As a concrete use-case, we implement an entire hyperdimensional computing framework in RTM to accelerate the language recognition problem. Our evaluation shows considerable performance and energy improvements compared to conventional Von-Neumann models and state-of-the-art accelerators

Casco Bay Weekly : 19 February 2004

https://digitalcommons.portlandlibrary.com/cbw_2004/1007/thumbnail.jp

Routledge Handbook of Public Policy in Africa

This Handbook provides an authoritative and foundational disciplinary overview of African Public Policy and a comprehensive examination of the practicalities of policy analysis, policymaking processes, implementation, and administration in Africa today. The book assembles a multidisciplinary team of distinguished and upcoming Africanist scholars, practitioners, researchers and policy experts working inside and outside Africa to analyse the historical and emerging policy issues in 21st-century Africa. While mostly attentive to comparative public policy in Africa, this book attempts to address some of the following pertinent questions: • How can public policy be understood and taught in Africa? • How does policymaking occur in unstable political contexts, or in states under pressure? • Has the democratisation of governing systems improved policy processes in Africa? • How have recent transformations, such as technological proliferation in Africa, impacted public policy processes? • What are the underlying challenges and potential policy paths for Africa going forward? The contributions examine an interplay of prevailing institutional, political, structural challenges and opportunities for policy effectiveness to discern striking commonalities and trajectories across different African states. This is a valuable resource for practitioners, politicians, researchers, university students, and academics interested in studying and understanding how African countries are governed