Hydra, a new framework for increasing the speed and power of general-purpose computers, without adding hardware or silicon, is described in this paper. Hydra exploits existing but untapped computing potential of devices that harbor capabilities similar to central processing units (CPUs). For example, any network interface controller (NIC) has a CPU, disk controllers are programmable, and high-end graphic units have compute engines often stronger than their host CPU. Hydra taps this computing potential through support in the operating system (OS), so that the relocation (offloading) of some computing steps from the CPU to the programmable device is transparent not only to the user, but also to the software application being accelerated.

After the introduction in Section 1, Section 2 presents the Hydra system requirements for offloading and describes technical challenges. Section 3 reviews the programming model, and Section 4 discusses the architecture for offloading. Section 5 shows a mathematical formulation of complex offloading scenarios. Section 6 provides a case study for developing an offload-aware application, and evaluates the resulting performance improvement. Finally, Section 7 compares related work, Section 8 discusses future directions, and Section 9 concludes the discussion.

The architecture section is very high level, and would have benefited from thorough coverage of at least one level of detail lower. Anyone using Hydra will have to contact the authors. Moreover, it is not clear when the total investment in additional programming and higher OS complexity is worth the return. A discussion of business models in which Hydra actually returns the investment would help.

Aside from these minor issues, the paper is of clear value, as are the Hydra concept and its future derivatives. The fact that Weinsberg et al. actually implemented a Hydra framework and quantified and compared offload improvements across a variety of technical choices is helpful and renders the concept credible. A modicum of playful political correctness through use of the personal pronoun “she,” in addition to an impeccable writing style, renders the paper exquisitely readable and the ideas easily comprehensible. Development engineers and researchers wishing to develop methods of increasing a system’s computing power, without adding more CPUs or hyperthreads to silicon, must study this paper. Also, owners of very large banks of servers who are thinking about upgrading their tightly packed blades should read this paper before discarding the old banks of computers.