Mohamed Ben-Romdhane

Extending the transaction level modeling approach for fast communication architecture exploration

System-on-chip (SoC) designs are increasingly becoming more complex. Efficient on chip communication architectures are critical for achieving desired performance in these systems. System designers typically use Bus Cycle Accurate (BCA) models written in high level languages such as C/C++ to explore the communication design space. These models capture all of the bus signals and strictly maintain cycle accuracy, which is useful for reliable performance exploration but results in slow simulation speeds for complex designs, even when they are modeled using high level languages. Recently there have been several efforts to use the Transaction Level Modeling (TLM) paradigm for improving simulation performance of BCA models. However these BCA models capture a lot of details that can be eliminated when exploring communications architectures.

Floorplan-aware automated synthesis of bus-based communication architectures

As system-on-chip (SoC) designs become more complex, it is becoming harder to design communication architectures to handle the ever increasing volumes of inter-component communication. Manual traversal of the vast communication design space to synthesize a communication architecture that meets performance requirements becomes infeasible. In this paper, we address this problem by proposing an automated approach for synthesizing cost-effective, bus-based communication architectures that satisfy the performance constraints in a design. Our synthesis flow also incorporates a high-level floorplanning and wire delay estimation engine to evaluate the feasibility of the synthesized bus architecture and detect timing violations early in the design flow. We present case studies of network communication SoC subsystems for which we synthesized bus architectures, detected timing violations and generated core placements in a matter of hours instead of several days it took for a manual effort.

Constraint-driven bus matrix synthesis for MPSoC

Modern multi-processor system-on-chip (MPSoC) designs have high bandwidth constraints which must be satisfied by the underlying communication architecture. Bus matrix based communication architectures consist of several parallel buses which provide a suitable backbone to support high bandwidth systems, but suffer from high cost overhead due to extensive bus wiring inside the matrix. Manual traversal of the vast exploration space to synthesize a minimal cost bus matrix that also satisfies performance constraints is practically infeasible. In this paper, we address this problem by proposing an automated approach for synthesizing a bus matrix communication architecture which satisfies all performance constraints in the design and minimizes wire congestion in the matrix. To validate our approach, we consider several industrial strength applications from the networking domain and show that our approach results in up to 9times component savings when compared to a full bus matrix and up to 3.2times savings when compared to a maximally connected reduced bus matrix

FABSYN: floorplan-aware bus architecture synthesis

As system-on-chip (SoC) designs become more complex, it is becoming harder to design communication architectures to handle the ever increasing volumes of inter-component communication. Manual traversal of the vast communication design space to synthesize a communication architecture that meets performance requirements becomes infeasible. In this paper, we address this problem by proposing an automated approach for floorplan-aware bus architecture synthesis (FABSYN) to synthesize cost-effective, bus-based communication architectures that satisfy the performance constraints in a design. Our synthesis approach incorporates a high-level floorplanning and wire delay estimation engine to evaluate the feasibility of the synthesized bus architecture and detect bus cycle time violations early in the design How, at the system level. We present case studies of network communication SoC subsystems for which we synthesized bus architectures, detected and eliminated timing violations, and generated core placements in a matter of hours instead of several days for a manual effort.

BMSYN: Bus Matrix Communication Architecture Synthesis for MPSoC

Modern multiprocessor system-on-chip designs have high bandwidth constraints which must be satisfied by the underlying communication architecture. Traditional hierarchical shared bus communication architectures can only support limited bandwidths and are not scalable for very high-performance designs. Bus matrix-based communication architectures consist of several parallel busses which provide a suitable backbone to support high-bandwidth systems but suffer from high-cost overhead due to extensive bus wiring inside the matrix. Manual traversal of the vast exploration space to synthesize a minimal cost bus matrix that also satisfies performance constraints is practically infeasible. In this paper, we address this problem by proposing an automated approach for synthesizing a bus matrix communication architecture, which satisfies all performance constraints in the design and minimizes wire congestion in the matrix. To validate our approach, we consider several industrial strength applications from the networking domain and show that our approach results in up to 9times component savings when compared to a full bus matrix, and up to 3.2times savings when compared to a maximally connected reduced bus matrix, while satisfying all performance constraints in the design.

Using TLM for exploring bus-based SoC communication architectures

As billion transistor system-on-chips (SoC) become commonplace and design complexity continues to increase, designers are faced with the daunting task of meeting escalating design requirements in shrinking time-to-market windows, and have begun using an IP-based SoC design methodology that permits reuse of key SoC functional components. Since the communication architectures connecting components in these SoC designs significantly impact system performance, it is imperative that designers explore the communication design space efficiently, quickly and early in the design flow. Transaction level modeling (TLM) is an emerging abstraction that facilitates early exploration of SoC architectures. This paper outlines a typical IP-based SoC design flow, and presents the cycle count accurate at transaction boundaries (CCATB) modeling abstraction which is a fast, efficient and flexible approach for exploring bus-based communication architectures in SoC designs. The CCATB models not only take less time to model but are also faster to simulate than existing modeling abstractions for communication architecture exploration such as pin-accurate BCA (PA-BCA) and transaction based BCA (T-BCA). Experimental results on several industrial SoC subsystem case studies show that CCATB models are faster than PA-BCA by as much as 120% on average and by 67% on average when compared to T-BCA, demonstrating the advantages of CCATB-based TLM abstraction for exploring bus-based SoC communication architectures.

Fast exploration of bus-based communication architectures at the CCATB abstraction

Currently, system-on-chip (SoC) designs are becoming increasingly complex, with more and more components being integrated into a single SoC design. Communication between these components is increasingly dominating critical system paths and frequently becomes the source of performance bottlenecks. It, therefore, becomes imperative for designers to explore the communication space early in the design flow. Traditionally, system designers have used Pin-Accurate Bus Cycle Accurate (PA-BCA) models for early communication space exploration. These models capture all of the bus signals and strictly maintain cycle accuracy, which is useful for reliable performance exploration but results in slow simulation speeds for complex, designs, even when they are modeled using high-level languages. Recently, there have been several efforts to use the Transaction-Level Modeling (TLM) paradigm for improving simulation performance in BCA models. However, these transaction-based BCA (T-BCA) models capture a lot of details that can be eliminated when exploring communication architectures. In this paper, we extend the TLM approach and propose a new transaction-based modeling abstraction level (CCATB) to explore the communication design space. Our abstraction level bridges the gap between the TLM and BCA levels, and yields an average performance speedup of 120&percent; over PA-BCA and 67&percent; over T-BCA models, on average. The CCATB models are not only faster to simulate, but also extremely accurate and take less time to model compared to both T-BCA and PA-BCA models. We describe the mechanisms that produce the speedup in CCATB models and also analyze how the achieved simulation speedup scales with design complexity. To demonstrate the effectiveness of using CCATB for exploration, we present communication space exploration case studies from the broadband communication and multimedia application domains.

Automated throughput-driven synthesis of bus-based communication architectures

As system-on-chip (SoC) designs become more complex, it becomes increasingly harder to design communication architectures which satisfy design constraints. Manually traversing the vast communication design space for constraint-driven synthesis is not feasible any more. In this paper we propose an approach that automates the synthesis of bus-based communication architectures for systems characterized by (possibly several) throughput constraints. Our approach accurately and effectively prunes the large communication design space to synthesize a feasible low-cost bus architecture which satisfies the constraints in a design.

System level design: six success stories in search of an industry

This panel will bring six speakers relating their success stories about design starting at the system-level. The format is an educational Panel aimed at informing DAC attendees of the challenges (difficulties and pitfalls) and opportunities (sizable benefits and lessons learned from these experiences).