IEEE Micro

Guest Editors' Introduction: Interaction of Many-Core Computer Architecture and Operating Systems

Rapid changes in platform hardware resources with the evolution of many-core architectures will require a fundamental reexamination of mainstream system-software design decisions to support multiple cores and to efficiently manage on-chip hardware resources shared among the multiple cores. In turn, the evolution of many-core processor architectures will be successfully sustained by the new capabilities and features added to the system software, perhaps while requiring substantial support from hardware. The guest editors introduce five articles on the interaction of computer architecture and operating systems for this special issue of IEEE Micro.

Multicore Resource Management

Current resource management mechanisms and policies are inadequate for future multicore systems. Instead, a hardware/software interface based on the virtual private machine abstraction would allow software policies to explicitly manage microarchitecture resources. VPM policies, implemented primarily in software, translate application and system objectives into VPM resource assignments. Then, VPM mechanisms securely multiplex, arbitrate, or distribute hardware resources to satisfy the VPM assignments.

The Impact of Dynamically Heterogeneous Multicore Processors on Thread Scheduling

Although most current multicore processors are homogeneous, microarchitects are now proposing heterogeneous core implementations, including systems in which heterogeneity is introduced at runtime. This article shows that operating system schedulers must consider dynamic heterogeneity or suffer significant power-efficiency and performance losses.

Using Asymmetric Single-ISA CMPs to Save Energy on Operating Systems

CPUs consume too much power. Modern complex cores sometimes waste power on functions that are not useful for the code they run. In particular, operating system kernels do not benefit from many power-consuming features intended to improve application performance. We advocate asymmetric single-ISA multicore systems, in which some cores are optimized to run OS code at greatly improved energy efficiency.

System-Level Performance Metrics for Multiprogram Workloads

Assessing the performance of multiprogram workloads running on multithreaded hardware is difficult because it involves a balance between single-program performance and overall system performance. This article argues for developing multiprogram performance metrics in a top-down fashion starting from system-level objectives. The authors propose two performance metrics: average normalized turnaround time, a user-oriented metric, and system throughput, a system-oriented metric.

Using OS Observations to Improve Performance in Multicore Systems

Today's operating systems don't adequately handle the complexities of Multicore processors. Architectural features confound existing OS techniques for task scheduling, load balancing, and power management. This article shows that the OS can use data obtained from dynamic runtime observation of task behavior to ameliorate performance variability and more effectively exploit multicore processor resources. The authors' research prototypes demonstrate the utility of observation-based policy.

AAI Asks FTC to Investigate RAND Issues Concerning Digital TV Standard

The American Antitrust Institute has asked the Federal Trade Commission to begin an investigation of Rembrandt Inc., an owner of patents relating to the digital television broadcasting standard that the Federal Communications Commission has mandated for use by TV broadcasters. Richard Stern investigates the idea of reasonable and nondiscriminatory licensing in the context of two-tier markets.