  Developers are usually unaware of the impact of code changes to the
performance of software systems. Although developers can analyze the
performance of a system by executing, for instance, a performance test to
compare the performance of two consecutive versions of the system, changing
from a programming task to a testing task would disrupt the development flow.
In this paper, we propose the use of a city visualization that dynamically
provides developers with a pervasive view of the continuous performance of a
system. We use an immersive augmented reality device (Microsoft HoloLens) to
display our visualization and extend the integrated development environment on
a computer screen to use the physical space. We report on technical details of
the design and implementation of our visualization tool, and discuss early
feedback that we collected of its usability. Our investigation explores a new
visual metaphor to support the exploration and analysis of possibly very large
and multidimensional performance data. Our initial result indicates that the
city metaphor can be adequate to analyze dynamic performance data on a large
and non-trivial software system.
