CSR:Small:Kalipers-Deep Energy Inspection of Operating System Components

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

The electrical power used by all classes of computers is becoming of increasing importance. A major component of the cost of running large server operations is power, and, on the other end, the utility of laptops, palmtops, pads, and other portable devices is highly constrained by their batteries? capacity to power operations. One important element of the power used by computers is that burned by the operating system, the software that controls the computer?s operation. Little is known about the impact different operating system options have on a machine?s power budget, due to difficulties with existing technology in precisely measuring power use and correctly ascribing power expended to its true source. Thus, determining if scheduling algorithm alternatives, different forms of memory management, or different security options offered by the operating system have good, bad, or neutral power impacts has been difficult. The Kalipers project will address this issue by using new technology to obtain detailed and reliable information about how important operating system components affect machine power use. Kalipers will achieve this goal through a program of experimentation using a unique hardware/software platform called LEAP. The LEAP platform, which we have already built and tested, allows fine-grained assignments of power use to particular piece of code. It also measures the differing power consumption by important system components, such as the CPU, the memory, and the hard drive. We will use the LEAP?s capabilities to determine how operating system actions and decisions affect the power use of platforms that have strong needs to minimize their power budget. Our experiments will be concentrated in three areas: file systems, memory management, and security services. These are areas we have experience in and where we have reason to believe power savings can be found. We will investigate alternative technologies (such as the power costs of different file systems, or software vs. hardware full disk encryption). The LEAP technology will allow us to dive more deeply into the power costs of different system components, allowing us to shed light on issues like the degree to which higher power costs for ext3 are due to its implementation details and the degree to which they are inherent in the journaling nature of that file system. We will also reimplement key components of the operating system to demonstrate how the knowledge we have gained can be used to improve a system?s power consumption.