  The growing capacity of integration allows to instantiate hundreds of
soft-core processors in a single FPGA to create a reconfigurable
multiprocessing system. Lately, FPGAs have been proven to give a higher energy
efficiency than alternative platforms like CPUs and GPGPUs for certain
workloads and are increasingly used in data-centers. In this paper we
investigate whether many-soft-core processors can achieve similar levels of
energy efficiency while providing a general purpose environment, more easily
programmed, and allowing to run other applications without reconfiguring the
device. With a simple application example we are able to create a
reconfigurable multiprocessing system achieving an energy efficiency 58 times
higher than a recent ultra-low-power processor and 124 times higher than a
recent high performance GPGPU.
