Patrick J. Bohrer

Mambo: a full system simulator for the PowerPC architecture

Mambo is a full-system simulator for modeling PowerPC-based systems. It provides building blocks for creating simulators that range from purely functional to timing-accurate. Functional versions support fast emulation of individual PowerPC instructions and the devices necessary for executing operating systems. Timing-accurate versions add the ability to account for device timing delays, and support the modeling of the PowerPC processor microarchitecture. We describe our experience in implementing the simulator and its uses within IBM to model future systems, support early software development, and design new system software.

Design and validation of a performance and power simulator for PowerPC systems

This paper describes the design and validation of a performance and power simulator that is part of the Mambo simulation environment for PowerPC® systems. One of the most notable features of the simulator, designated as Tempo, is the incorporation of an event-driven power model. Tempo satisfies an important need for fast and accurate performance and power simulation tools at the system level. The power and performance predictions from the simulated model of a PowerPC 405GP (or simply 405GP) were validated against a 405GP-based evaluation board instrumented for power measurements using 42 application/dataset combinations from the EEMBC benchmark suite. The average performance and energy-prediction errors were 0.6% and -4.1%, respectively. In addition to describing Tempo, we show examples of how well it can predict the runtime power consumption of a 405GP microprocessor during application execution.

Application of full-system simulation in exploratory system design and development

This paper describes the design and application of a full-system simulation environment that has been widely used in the exploration of the IBM PowerPC® processor and system design. The IBM full-system simulator has been developed to meet the needs of hardware and software designers for fast, accurate, execution-driven simulation of complete systems, incorporating parameterized architectural models. This environment enables the development and tuning of production-level operating systems, compilers, and critical software support well in advance of hardware availability, which can significantly shorten the critical path of system development. The ability to develop early versions of software can benefit hardware development by identifying design issues that may affect functionality and performance far earlier in the development cycle, when they are much less costly to correct. In this paper, we describe features of the simulation environment and present examples of its application in the context of the Sony-Toshiba-IBM Cell Broadband EngineTM and IBM PERCS development projects.

IBM Bluemix Mobile Cloud Services

The Mobile Cloud Services offering of IBM Bluemix® is a platform for cloud-based mobile applications, providing data and file storage, application authentication, push notifications, and server-side application logic, all available through easy-to-use client software development kits (SDKs). In this paper, we describe the server-side architecture for the key components of the Mobile Cloud Services. For scalability and fault resilience, components are implemented as stateless services that communicate using a distributed message queue. We adopted a “design for failure” approach to all environmental services, including basic networking support. We developed a robust communications layer that adds timeout and retry logic to all external interactions. We also built a flexible and robust application-monitoring infrastructure to constantly probe the service components, test end-to-end functionality, and report any problems through web monitors and text messages. Finally, we designed and delivered client SDKs for Android®, iOS®, and JavaScript® that enable application developers to quickly create robust mobile applications that utilize IBM Mobile Cloud Services. These architecture and implementation choices have resulted in a robust and scalable cloud-based platform for mobile application developers.

System Management with IBM Mobile Systems Remote: A Question of Power and Scale

The rise of the app revolution has brought small, simple, and affordable software tools to users for mastering mundane tasks with the help of mobile devices. With the success of the app paradigm, there is an increasing demand for applying the same spirit to problems which have traditionally been the domain of enterprise-scale solutions, e.g., system management. The challenge for building such communication-intensive applications, however, is to gather the health and performance data of a large number of machines in an agile and responsive fashion while being restricted by the scarce resources and severe power constraints inherent to mobile devices. In this paper, we present a system architecture that tackles this fundamental challenge by making data freshness an explicit concern and allowing the application to express its freshness requirements in a fine-grained way. The application runs atop a generic data cache and collection engine that fetches fresh data from the management endpoints based on these requirements. We evaluate the performance and power consumption characteristics on a broad range of Android-based mobile devices and show that this approach increases the responsiveness of the application while at the same time reducing the power consumption.