In this paper, we propose an accurate cycle estimation framework which allows to use multiple instruction set simulators to simulate not only processors but also diverse peripheral devices. An instruction set simulator runs on a host machine to mimic functional behaviors of instructions running on a target hardware. It allows to estimate the execution time of software in a fast and accurate way and validate a system even when its target hardware does not yet exist or is not available.

A variety of advantages from sounds such as measurement and accessibility introduces a new opportunity for mobile applications to offer broad types of interesting, valuable functionalities, supporting a richer user experience. However, in spite of the growing interests on mobile sound applications, few or no works have been done in focusing on managing an audio device effectively. More specifically, their low level of real-time capability for audio resources makes it challenging to satisfy tight timing requirements of mobile sound applications, e.g., a high sensing rate of acoustic sensing applications. To address this problem, this work presents the SounDroid framework, an audio device management framework for real-time audio requests from mobile sound applications. The design of SounDroid is based on the requirement analysis of audio requests as well as an understanding of the audio playback procedure including the audio request scheduling and dispatching on Android. It then incorporates both real-time audio request scheduling algorithms, called EDF-V and AFDS, and dispatching optimization techniques into mobile platforms, and thus improves the quality-of-service of mobile sound applications. Our experimental results with the prototype implementation of SounDroid demonstrate that it is able to enhance scheduling performance for audio requests, compared to traditional mechanisms (by up to 40% of improvement), while allowing deterministic dispatching latency.

No abstract available.

The last several years have seen a rapid increase in smart phone use. Android offers an open-source software platform on smart phones, that includes a Linux-based kernel, Java applications, and middleware. The Android middleware provides system libraries and services to facilitate the development of performance-sensitive or device-specific functionalities, such as screen display, multimedia, and web browsing. Android keeps track of which applications make use of which system services for some pre-defined functionalities, and which application is running in the foreground attracting the user's attention. Such information is valuable in capturing application characteristics and can be useful for resource management tailored to application requirements. However, the Linux-based Android kernel does not utilize such information for I/O resource management. This paper is the first work, to the best of our knowledge, to attempt to understand application characteristics through Android architecture and to incorporate those characteristics into disk and network I/O management. Our proposed approach, Aciom (Application Characteristics-aware I/O Management), requires no modification to applications and characterizes application I/O requests as time-sensitive, bursty, or plain, depending on which system services are involved and which application receives the user's focus. Aciom then provides differentiated I/O management services for different types of I/O requests, supporting minimum bandwidth reservations for time-sensitive requests and placing maximum bandwidth limits on bursty requests. We present the design of Aciom and a prototype implementation on Android. Our experimental results show that Aciom is quite effective in handling disk and network I/O requests in support of time-sensitive applications in the presence of bursty I/O requests.