Dr. Pranav Ashar
Dr. Pranav Ashar is chief technology officer at Real Intent. He previously worked at NEC Labs developing formal verification technologies for VLSI design. With 35 patents granted and pending, he has authored about 70 papers and co-authored the book ‘Sequential Logic Synthesis’.
Executive Insight: On the Convergence of Design and Verification
August 7th, 2014 by Dr. Pranav Ashar
This article was originally published on TechDesignForums and is reproduced here by permission.
Sometimes it’s useful to take an ongoing debate and flip it on its head. Recent discussion around the future of simulation has tended to concentrate on aspects best understood – and acted upon – by a verification engineer. Similarly, the debate surrounding hardware-software flow convergence has focused on differences between the two.
Pranav Ashar, CTO of Real Intent, has a good position from which to look across these silos. His company is seen as a verification specialist, particularly in areas such as lint, X-propagation and clock domain crossing. But talk to some of its users and you find they can be either design or verification engineers.
How Real Intent addresses some of today’s challenges – and how it got there – offer useful pointers on how to improve your own flow and meet emerging or increasingly complex tasks.
“We’ve seen this and said this before, but for today’s big systems, you don’t want to do a lot of separate design and verification,” Ashar says. “Each represents a major project in itself and until now each has required its own process. When things become as complex as they have, you have to interweave them.
“This isn’t just because it is inherently more efficient. The level of complexity is such that it becomes predictable that the boundary between the two will blur. That’s happening and it will continue to happen. It’s critical to understand that it is almost a natural evolution.”
The next issue is how to communicate this and the flow changes it requires on both sides of the D&V divide. In some cases, you don’t. Instead, you present information to different communities in the way they most easily understand given existing working practices.
In Real Intent’s latest update to Ascent XV (its X-verification and reset suite), the company worked from the assumption that different disciplines look at things in different ways. The verification engineer concentrates on X-related issues; the design engineer wants detail on resets, power management schemes and proliferating clocks. The company tailored the tool’s interfaces and outputs accordingly.
Real Intent is not alone in adopting this approach. But perhaps it is only a beginning.
Fuzzy verification boundaries
Ashar draws a useful comparison with the ongoing debate over hardware-software co-design, and the similar tailoring of tools to users that it has seen.
“The underlying technologies for hardware and software are in many respects very similar. For example, execution paths are important on both sides. Having said that, though, the computational paradigms are different as are the data management procedures. Aspects like that, right now, explain why debug tools have different flavors, why they are presented to the user in different ways,” he notes.
“But, in terms of this whole hardware/software debate, we still seem to talk more about two separate worlds. Where there seems to be less discussion is, again, in terms of these fuzzy boundaries. So, we don’t talk much about how the hardware is increasingly looking like the software. Yet, the abstraction layers above RTL do look more and more like software algorithms, and they are becoming a lot more important in terms of how a system is assembled.”
Coming back to the world of verification, Ashar suggests an approach that, while it may not define two different disciplines, could more closely align them.
“Simulation,” he says, “is a last resort. It largely comes about because of things that we do not understand. It is a back stop.”