How to Verify Performance of Complex Interconnect-Based Designs?

With more and more SoCs employing sophisticated interconnect IP to link multiple processor cores, caches, memories, and dozens of other IP functions, the designs are enabling a new generation of low-power servers and high-performance mobile devices. The complexity of the interconnects and their advanced configurability contributes to already formidable design and verification challenges which lead to the following questions:

While your interconnect subsystem might have a correct functionality, are you starving your IP functions of the bandwidth they need? Are requests from latency-critical initiators processed on time? How can you ensure that all applications will receive the desired bandwidth in steady-state and corner use-cases?

To answer these questions, Cadence recommends the Performance Verification Methodology to ensure that the system performance meets requirements at the different levels:

1. Performance characterization: The first level of verification aims to verify the path-to-path traffic measuring the performance envelope. It targets integration bugs like clock frequency, buffer sizes, and bridge configuration. It requires to analyze the latency and bandwidth of design’s critical paths.
2. Steady state workloads: The second level of verification aims to verify the master-by-master defined loads using traffic profiles. It identifies the impact on bandwidth when running multi-master traffic with various Quality-of-Service (QoS) settings. It analyzes the DDR sub-system’s efficiency, measures bandwidth and checks whether masters’ QoS requirements are met.
3. Application specific use cases: The last level of verification simulates the use-cases and reaches the application performance corner cases. It analyzes the master-requested bandwidth as well as the DDR sub-system’s efficiency and bandwidth.

Cadence has developed a set of tools to assist customers in performance validation of their SoCs. Cadence Interconnect Workbench simplifies the setup and measurement of performance and verification testbenches and makes debugging of complex system behaviors a snap. The solution works with Cadence Verification IPs and executes on the Cadence Xcelium® Enterprise Simulator or Cadence Palladium® Accellerator/Emulator, with coverage results collected and analyzed in the Cadence vManager Metric-Driven Signoff Platform.

To verify the performance of the Steady State Workloads, Arm has just released a new AMBA Adaptive Traffic Profile (ATP) specification which describes AMBA abstract traffic attributes and defines the behavior of the different traffic profiles in the system.

With the availability of Cadence Interconnect Workbench and AMBA VIP support of ATP, early adopters of the AMBA ATP specification can begin working immediately, ensuring compliance with the standard, and achieving the fastest path to SoC performance verification closure.

For more information on the AMBA Adaptive Traffic Profile, you can visit Dimitry's blog on AMBA Adaptive Traffic Profiles: Addressing The Challenge. 

More information on Cadence Interconnect Workbench solution is available at Cadence Interconnect Solution webpage.

Thierry