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Heterogeneous architectures that integrate a mix of big and small cores are very attractive because they can achieve high single-threaded performance while enabling high performance thread-level parallelism with lower energy costs. Despite their benefits, they pose significant challenges to the operating system software. Thread scheduling is one of the most(More)
Recent research advocates asymmetric multi-core architectures, where cores in the same processor can have different performance. These architectures support single-threaded performance and multithreaded throughput at lower costs (e.g., die size and power). However, they also pose unique challenges to operating systems, which traditionally assume homogeneous(More)
Over the last decade, homogeneous multi-core processors emerged and became the de-facto approach for offering high parallelism, high performance and scalability for a wide range of platforms. We are now at an interesting juncture where several critical factors (smaller form factor devices, power challenges, need for specialization, etc) are guiding(More)
A heterogeneous processor consists of cores that are asymmetric in performance and functionality. Such a design provides a cost-effective solution for processor manufacturers to continuously improve both single-thread performance and multi-thread throughput. This design, however , faces significant challenges in the operating system, which traditionally(More)
Fairness is an essential requirement of any operating system scheduler. Unfortunately, existing fair scheduling algorithms are either inaccurate or inefficient and non-scalable for multiprocessors. This problem is becoming increasingly severe as the hardware industry continues to produce larger scale multi-core processors. This paper presents <i>Distributed(More)
This paper discusses an approach for supporting soft real-time periodic tasks in Linux on performance asymmetric multicore platforms (AMPs). Such architectures consist of a large number of processing units on one or several chips, where each processing unit is capable of executing the same instruction set at a different performance level. We discuss(More)
Typically, reversible posterior leukoencephalopathy syndrome (RPLS) involves the parieto-occipital lobes. When regions of the brain other than the parieto-occipital lobes are predominantly involved, the syndrome can be called atypical RPLS. The purpose of this study is to find radiological and pathophysiological features of atypical RPLS by using(More)
Heterogeneous multicore processors (HMPs), consisting of cores with different performance/power characteristics , have been proposed to deliver higher energy efficiency than symmetric multicores. This paper investigates the opportunities and limitations in using HMPs to gain energy-efficiency. Unlike previous work focused on server systems, we focus on the(More)
The Linux kernel 2.6.23 scheduler includes substantial changes that may entice researchers with no prior interest in Linux to attempt to understand or modify its behavior. Often, this is no easy task, particularly for someone new to Linux kernel development. Virtual machines and hardware simulators can help make the task easier; however, they introduce(More)