Joachim Keinert

IBM POWER6 microprocessor physical design and design methodology

The IBM POWER6™ microprocessor is a 790 million-transistor chip that runs at a clock frequency of greater than 4 GHz. The complexity and size of the POWER6 microprocessor, together with its high operating frequency, present a number of significant challenges. This paper describes the physical design and design methodology of the POWER6 processor. Emphasis is placed on aspects of the design methodology, technology, clock distribution, integration, chip analysis, power and performance, random logic macro (RLM), and design data management processes that enabled the design to be completed and the project goals to be met.

Design methodology for the IBM POWER7 microprocessor

The IBM POWER7® microprocessor, which is the next-generation IBM POWER® processor, leverages IBMs 45-nm silicon-on-insulator (SOI) process with embedded dynamic random access memory to achieve industry-leading performance. To deliver this complex 567-mm2 die, the IBM design team made significant innovations in chip design methodology. This paper describes the most critical methodology innovations specific to POWER7 design, which were in modularity, timing closure, and design efficiency.

Design methods for attaining IBM System z9 processor cycle-time goals

Cycle-time targets were set for the IBM System z9TM processor subsystem prior to building the system, and achieving these targets was one of the biggest challenges we faced during hardware development. In particular, although the processor-subsystem cycle-time improvement was driven primarily by the technology migration from CMOS 9S (130-nm lithography) for the prior IBM System z990 to CMOS IOSO (90-nm lithography) for the new system, the cooling capability for the System z9 resulted from a direct migration of the System z990 implementation with very limited improvements. The higher device current leakage and power associated with the technology migration, combined with the fixed cooling capability, created a technology challenge in which the subsystem cycle time and performance were potentially limited by cooling capability. Our solution emphasized silicon technology development, chip design, and hardware characterization and tuning. Ultimately, the System z9 processor subsystem achieved operation at 1.7 GHz, which exceeded the original target.

Intuitive ECO synthesis for high performance circuits

In the IC industry, chip design cycles are becoming more compressed, while designs themselves are growing in complexity. These trends necessitate efficient methods to handle late-stage engineering change orders (ECOs) to the functional specification, often in response to errors discovered after much of the implementation is finished. Past ECO synthesis algorithms have typically treated ECOs as functional errors and applied error diagnosis techniques to solve them. However, error diagnosis methods are primarily geared towards finding a single change, and moreover, tend to be computationally complex. In this paper, we propose a unique methodology that can systematically incorporate human intuition into the ECO process. Our methodology involves finding a set of directly substitutable points known as functional correspondences between the original implementation and the new specification by using name-preserving synthesis and user hints, to diminish the size of the ECO problem. On average, our approach can reduce the size of logic changes by 94% from those reported in current literature. We then incorporate our logic ECO changes into an incremental physical synthesis flow to demonstrate its usability in an industrial setting. Our ECO synthesis methodology is evaluated on high-performance industrial designs. Results indicate that post-ECO worst negative slack (WNS) improved 14% and total negative slack (TNS) improved 46% over pre-ECO.