IDC: An Energy Efficient Communication Scheme for Connected Mobile Platforms

Mobile platforms (e.g. laptops) offer ubiquitous network connectivity through its wireless communication interfaces, with most of usage models driven by always-on communication activities. However this in turn creates significant power challenges as the battery life is a critical resource for all mobile platforms. While the communication device itself consumes a relatively small portion of the total power, the impact of communication on the overall platform power is significant, due to the non-deterministic nature of the network traffic, which tends to keep the platform busy more than necessary. In this paper, we extensively investigate characteristics of various real- world network-centric workloads, e.g., VoIP, web browsing, etc., and their impact on the mobile platform in terms of power consumption and energy. Based on the understandings, we propose, implement and evaluate an Interrupt /DMA (Direct Memory Access) Coalescing (IDC) scheme at the wireless network interface card (NIC). This scheme effectively reduces platform wakeups due to incoming network traffic, Another advantage of the scheme is that it requires only NIC modification at the receiving node, and is transparent to the user and the network. Using a commercial NIC with a laptop testing platform, we evaluate the power savings and performance impact of our proposed scheme. The measurements show that our scheme achieves significant platform power saving, around 25% of platform components, without impacting user experience.