Using complete machine simulation for software power estimation: the SoftWatt approach
Sudhanva Gurumurthi, Anand Sivasubramaniam, Mary Jane Irwin, N. Vijaykrishnan, Mahmut Kandemir, Tao Li, Lizy Kurian John
Abstract
Power dissipation has become one of the most critical factors for
the continued development of both high-end and low-end computer
systems. The successful design and evaluation of power
optimization techniques to address this vital issue is invariably
tied to the availability of a broad and accurate set of simulation
tools. Existing power simulators are mainly targeted for
particular hardware components such as CPU or memory systems and
do not capture the interaction between different system
components. In this work, we present a complete system power
simulator, called SoftWatt, that models the CPU, memory hierarchy
and a low-power disk subsystem and quantifies the power behavior of
both the application and operating system. This tool, built on top
of the SimOS infrastructure, uses validated analytical energy
models to identify the power hotspots in the system components,
capture relative contributions of the user and kernel code to the
system power profile, identify the power-hungry operating system
services and characterize the variance in kernel power profile
with respect to workload. Our results using Spec JVM98 benchmark
suite emphasize the importance of complete system simulation to
understand the power impact of architecture and operating system on
application execution.