In Search of an ESL Methodology In Search of an ESL Methodology

EDP 2006EDP 2006

Gary SmithGary Smith

Chief AnalystChief Analyst

Design & EngineeringDesign & Engineering

In Search of an ESL Methodology

By the end of 2004 it had become obvious that the migration to ESL Design had lost its way.

Most ESL Start-Ups claimed that they could do everything.

By ESL tool sales had stalled.

So Daya and I set out to find a practical ESL Methodology.

Starting in December of 2004 and ending in May of 2005, we carried out a series of surveys and conversations with engineers and vendors involved with ESL Design.

Algorithmic Design

The first thing that caught our eye was that almost all of the ESL Start-Ups had assumed that all designs started with an algorithm.

The next thing was that they all said that ESL design was only being done in Europe and Japan.

If you looked at the sales numbers that was true, only Europe and Japan were buying ESL tools.

The Survey We then began calling some of the top designers in the US,

Europe, Japan and Asia. The initial results were interesting.

In the US the answers were in general agreement. 1. Yes we do ESL Design. 2. Yes we use SystemC. 3. No we do not buy commercial tools; our tools are developed in house.

In Japan and Asia the answers were:1. Yes we do ESL Designs.2. Yes we use SystemC.3. Yes we use commercial ESL tools. (They could use a lot of improvement but they do work.)

The Survey in Europe This is when it became real interesting.

Some of the engineers reported:1. Yes we do ESL Designs.2. Yes we use SystemC.

3. Yes we use commercial ESL tools. (They could use a lot of improvement but they do work.)

Some of the engineers reported:1. Yes we do ESL Designs.2. Yes we use SystemC.

3. No we do not buy commercial tools, but we need some desperately.

Interestingly enough these answers came from the same companies.

Algorithmic Design ? The engineers that used commercial ESL tools were from the

Consumer divisions of European companies.

The engineers that complained about the lack of ESL tools were generally from the Automotive division of European companies with some responses from Telecom divisions of European companies.

The difference from the US was that the engineers that complained about the lack of ESL tools saw how productive ESL tools were in their Consumer divisions and wanted the same productivity improvement. Unfortunately the same tools were useless for their design work.

In general the US engineers had given up on the EDA Industry providing them ESL tools for their design flow.

The Methodology Survey

That started the second survey, where we asked System Engineers how they designed their systems (or sub-systems).

We discovered three basic Methodologies.1. Algorithmic Methodology2. Processor/Memory Methodology3. Control Logic Methodology

Then we stumbled on the disagreement over Platform-Based Design.

The New ESL Landscape 2005

Behavioral Level

2. Platform-Based Design

2. Platform-Based Design

2. Platform-Based Design

1. Architectural Design

1. Architectural Design

1. Architectural Design

Architectural LevelArchitectural LevelArchitectural Level

Hardware-Software Partitioning

Behavioral Level Behavioral Level

Control Logic Methodology

Processor/Memory Methodology

Algorithmic Methodology

ESL Verification

Other ESL Tools

The Algorithmic Methodology These designs start with Algorithmic development.

This is where optimization of the Algorithm is the primary task. Processor/Memory and Control Logic optimization were secondary.

This is the most mature to date, being used in both Europe and Japan.

It is typically a Platform-Based Design methodology.

The Europeans tend to optimize at the ES Behavioral Level, the Japanese at the ES Architectural Level.

The major challenges are:- Minimization of Power Consumption- How do you program it ?

The Microprocessor/Memory Methodology

These designs start with C/C++ models. The lack of Behavioral Modeling standards are a major issue.

They look at optimizing performance (throughput vs. power)- Use of main memory, use of cache memory- Heterogeneous vs. Homogeneous

These tools are generally being developed In-House.

Same problems as the Algorithmic Methodology, power and programmability.

We badly need a Concurrent Software Compiler.

The Control Logic Methodology These designs are generally started with State Charts.

The primary task is optimization of the Control Logic (as is the case in RTL design), Algorithmic or Processor/Memory optimization is either secondary or non-existent.

This is the least developed methodology.

Most of the tools we’ve seen are being developed In-House.

One comment was that a processor is the new gate in SoC design. But what about the Power and Programming Problems ?

We need a non-proprietary language ESL Control Logic Synthesizer.

Platform-Based Design Today

Platforms today are the System in a Platform-Based SoC Design

In a Platform-Based design the ESL Behavioral trade-offs are performed when the Platform is initially being developed. Usually by the Semiconductor Vendor

This could be the difference between Japan and Europe; European System vendors tend to design their own Platforms, Japanese System vendors use Platforms developed by Semiconductor vendors.

Platform-Based Design Today II

The designer using the platform does his optimizations at the ESL Architectural level. This has been causing Local Minimization problems.

We are seeing a move from Platform-Based Design to Architectural Design, in general to improve product differentiation.

We are also seeing Verification becoming the major cost issue in Platform-Based Design.

Platform-Based Design Tomorrow

We are now seeing multiple platforms being used in an SoC.

In this case Platforms have become components of the design and therefore can be addressed more easily during the ESL Behavioral phase of the design.

This allows optimal Hardware/Software partitioning.

However this is also causing major programming issues.

Conclusion

There are three main ESL Methodologies:1. Algorithmic Methodology2. Processor/Memory Methodology3. Control Logic Methodology

At the Architectural Level there are two sub-Methodologies:1. Architectural Design2. Platform-Based Design

Recommendations

The three major ESL problems today are:1. Concurrent Programming (Amdahl’s Law)2. Power Optimization3. The Architect’s Workbench

To complete the ESL Flows we need:1. Behavioral Modeling standards 2. A Concurrent Software Compiler3. A non-proprietary language ESL Control Logic Synthesizer