Lax: Driver Interfaces for Approximate Sensor Device Access
Phillip Stanley‐Marbell, Martin Rinard, · 2015
Embedded sensor platforms can dissipate most of their en-ergy in accessing sensor integrated circuits such as gyro-scopes. But the algorithms which process the sensor data and the humans who consume the overall output of the system may often be able to tolerate some amount of error in the re-trieved sensor values. Because devices are accessed through interfaces provided by system software, exploiting the toler-able error for improvements in energy efficiency requires ap-propriate system software and hardware support. However, no such support currently exists. We present Lax, a device driver abstraction for interacting with sensors that enables power savings in exchange for oc-casionally returning erroneous sensor data. Our implementa-tion on a hardware prototype delivers savings in sensor dy-namic power dissipation of up to 48 % (as compared to pre-cise device access) while providing sensor access error rates lower than 5 data acquisition errors per 100 data accesses. Given the significant proportion of system energy budgets in wearable platforms that are devoted to sensors, approxi-mate sensor data acquisition using Lax can deliver signifi-cant system-level energy savings. 1.