Traditional IP design faces challenges imposed by performance requirements, power and area budgets, and cost and time-to-market limitations. The design, verification, and integration of security IP introduces additional challenges due to the need to protect secure keys both within the design and during the product lifecycle. This paper highlights many of these security-specific challenges and describes strategies for addressing them.

Hardware modules would be much easier to reuse if they supported generic flexible high-level interfaces. However, these interfaces are rarely used since they lead to timing and area overheads compared to a customized design. This paper describes a reachability analysis framework that identifies over-provisioning in instances of flexible design, and offers a technique for annotating this information so that modern synthesis tools can remove most of the overhead. Results are demonstrated on a variety of flexible structures, including functional blocks, programmable state machines, and latency-insensitive interfaces.

Technology scaling has created a catch-22: technology now can do almost anything we want, but the NRE design costs are so high, that almost no one can afford to use it. Our current situation is reminiscent of the 1980's, when only a few companies could afford to produce custom silicon. Synthesis and placement and routing tools changed this, by providing modular tools with well defined interfaces that codified designer knowledge about the physical design of chips. Now we need a new set of tools that can codify designer knowledge about how to construct software, hardware, and validation to again enable application designers to produce chips. Researchers are developing methodologies that allow users to create hardware constructors, or generators. These include Genesis2, which extends SystemVerilog and enables the designer to encode hierarchical system construction procedurally. To demonstrate some of the capabilities that these languages and tools provide, we describe FPGen, a complete floating point generator written in Genesis2, that also generates the needed validation collateral and hints for the backend processes.

Creating parameterized “chip generators” has been proposed as one way to decrease chip NRE costs. While many approaches are available for creating or generating flexible data path elements, the design of flexible controllers is more problematic. The most common approach is to create a microcoded engine as the controller, which offers flexibility through programmable table-based lookup functions. This paper shows that after “programming” the hardware for the desired application, or applications, these flexible controller designs can be easily converted to efficient fixed (or less programmable) solutions using partial evaluation capabilities that are already present in most synthesis tools.

Due to their high volume, general-purpose processors, and now chip multiprocessors (CMPs), are much more cost effective than ASICs, but lag significantly in terms of performance and energy efficiency. This paper explores the sources of these performance and energy overheads in general-purpose processing systems by quantifying the overheads of a 720p HD H.264 encoder running on a general-purpose CMP system. It then explores methods to eliminate these overheads by transforming the CPU into a specialized system for H.264 encoding. We evaluate the gains from customizations useful to broad classes of algorithms, such as SIMD units, as well as those specific to particular computation, such as customized storage and functional units.

Building hardware prototypes for computer architecture research is challenging. Unfortunately, development of the required software tools (compilers, debuggers, runtime) is even more challenging, which means these systems rarely run real applications. To overcome this issue, when developing our prototype platform, we used the Tensilica processor generator to produce a customized processor and corresponding software tools and libraries. While this base processor was very different from the streamlined custom processor we initially imagined, it allowed us to focus on our main objective---the design of a reconfigurable CMP memory system---and to successfully tape out an 8-core CMP chip with only a small group of designers. One person was able to handle processor configuration and hardware generation, support of a complete software tool chain, as well as developing the custom runtime software to support three different programming models. Having a sophisticated software tool chain not only allowed us to run more applications on our machine, it once again pointed out the need to use optimized code to get an accurate evaluation of architectural features.

Verification of chip multiprocessor memory systems remains challenging. While formal methods have been used to validate protocols, simulation is still the dominant method used to validate memory system implementation. Having a memory scoreboard, a high-level model of the memory, greatly aids simulation based validation, but accurate score-boards are complex to create since often they depend not only on the memory and consistency model but also on its specific implementation. This paper describes a methodology of using a relaxed scoreboard, which greatly reduces the complexity of creating these memory models. The relaxed scoreboard tracks the operations of the system to maintain a set of values that could possibly be valid for each memory location. By allowing multiple possible values, the model used in the scoreboard is only loosely coupled with the specific design, which decouples the construction of the checker from the implementation, allowing the checker to be used early in the design and to be built up incrementally, and greatly reduces the scoreboard design effort. We demonstrate the use of the relaxed scoreboard in verifying RTL implementations of two different memory models, Transactional Coherency and Consistency (TCC) and Relaxed Consistency, for up to 32 processors. The resulting checker has a performance slowdown of 19% for checking Relaxed Consistency, and less than 30% for TCC, allowing it to be used in all simulation runs.

The drive for low-power, high performance computation coupled with the extremely high design costs for ASIC designs, has driven a number of designers to try to create a flexible, universal computing platform that will supersede the microprocessor. We argue that these flexible, general computing chips are trying to accomplish more than is commercially needed. Since design NRE costs are an order of magnitude larger than fabrication NRE costs, a two-step design system seems attractive. First, the users configure/program a flexible computing framework to run their application with the desired performance. Then, the system "compiles" the program and configuration, tailoring the original framework to create a chip that is optimized toward the desired set of applications. Thus the user gets the reduced development costs of using a flexible solution with the efficiency of a custom chip.

This paper proposes a new sensornet protocol design goal: visibility. Visibility into behaviors at the network level will simplify debugging and ease the development process. We argue that increasing visibility is the responsibility of the network protocols themselves, and not solely the responsibility of existing debugging tools. We describe a quantitative visibility metric to evaluate and compare protocols, where visibility is defined as the energy cost of diagnosing the cause of a behavior in a protocol. The design and evaluation of Pull Collection Protocol, a novel multi-hop collection protocol, is an example of how to design for visibility without sacrificing throughput or node-level fairness. We also describe our optimizations for an existing protocol, Deluge, to increase its visibility and efficiency.