Posts Tagged ‘Synopsys Lynx’

The Missing Lynx - The ASIC Cloud

Friday, April 3rd, 2009

My last blog post, entitled The Weakest Lynx, got a lot of attention from the Synopsys Lynx CAEs and Synopsys marketing. Please go see the comments on that post for a response from Chris Smith, the lead support person for Lynx at Synopsys. Meanwhile, the final part of this series … The Missing Lynx.

About 7 months ago, I wrote a blog post entitled Birth of an EDA Revolution in which I first shared my growing excitement over the potential for cloud computing and Software-as-a-Service (SaaS) to transform EDA. About a week later, Cadence announced a SaaS offering that provides their reference flows, their software, and their hardware for rent to projects on a short-term basis. About a week after that, I wrote a third post on this topic, asking WWSD (what will Synopsys do) in response to Cadence.

In that last post, I wrote the following:

Synopsys could probably go one better and offer a superior solution if it wanted to, combining their DesignSphere infrastructure and Pilot Design Environment.  If fact, they have done this for select customers already, but not as a standard offering. There is some legwork that they’d need to do, but the real barrier is Synopsys itself. They’ve got to decide to go after this market and put together a standard offering like Cadence has … And while they are at it, if they host it on a secure cloud to make it universally accessible and scalable, and if they offer on-demand licensing, and if they make it truly open by allowing third party tools to plug into their flow, they can own the high ground in the upcoming revolution.

Although I wrote this over 6 months ago, I don’t think I could have written it better today. The only difference is that Pilot has now become Lynx. “The ASIC Cloud”, as I call it, would look something like this:

The ASIC Cloud

As I envision it, Synopsys Lynx will be the heart of The ASIC Cloud and will serve to provide the overall production design flow. The Runtime Manager will manage the resources including provisioning of additional hardware (CPU and storage) and licenses, as needed. The management cockpit will provide real-time statistics on resource utilization so the number of CPUs and licenses can be scaled on-the-go. Since The ASIC Cloud is accessible through any web browser, this virtual design center is accessible to large corporate customers and to smaller startups and consultants. It’s also available to run through portable devices such as netbooks and smartphones.

If you think I’m insane, you may be right, I may be crazy. But it just might be a lunatic you’re looking for. To show you that this whole cloud computing thing is not just my fever (I have been sick this past week), take a look at what this one guy in Greece did with Xilinx tools. He basically pays < $1 per hour to access hardware to run Xilinx synthesis tools on the Amazon Elastic Compute Cloud. Now, this is nothing like running an entire RTL2GDSII design flow, but he IS running EDA tools on the cloud, taking advantage of pay-as-you go CPU and storage resources, and taking advantage of multiple processors to speed up his turnaround time. The ASIC Cloud will be similar and on a much greater scale.

It may take some time for Synopsys to warm up to this idea, especially since it is a whole new business model for licensing software. But for a certain class of customers (startups, design services providers) it has definite immediate benefits. And many of these customers are also potential Lynx customers.

So, Synopsys, if you want to talk, you know where to find me.


That wraps up my 5-part series on Synopsys Lynx. If you want to find the other 4 parts, here they are:

Part 1 - Synopsys Lynx Design System Debuts at SNUG

Part 2 - Lynx Design System? - It’s The Flow, Stupid!

Part 3 - Strongest Lynx

Part 4 - The Weakest Lynx

harry the ASIC guy

The Weakest Lynx

Thursday, March 26th, 2009

Earlier this week I wrote about the strengths of the new Synopsys Lynx flow offering. Today, the weakest Lynx.

1. Limited 3rd-Party Tool Support.

Synopsys states that Lynx is “flexible and inherently configurable to readily incorporate 3rd-party technology”. And it is true that they have done nothing to prevent you from incorporating 3rd-party tools. They also have done little to help you incorporate these tools. In most cases, incorporating 3rd party tools means digging in to understand the guts of how Lynx works. That means getting down and dirty with makefiles and tcl scripts and mimicking all the special behavior of the standard Lynx scripts for Synopsys tools. For instance, here are a few of the things you might need to do:

  • Break up your tcl scripts into several tcl scripts in separate directories for the project and block
  • Access special Lynx environmental variables by name in your makefiles and TCL scripts
  • Have your tool output special SNPS_INFO messages formatted for the metrics GUI to parse out of the log file
  • Update your scripts for new versions of Lynx if any of these formats have changed.

If you are motivated, I’m sure you can hack through the scripts and figure it out. However, to my knowledge (I looked in Solvnet, correct me if I am wrong) there is no application note that clearly documents the steps needed and the relevant files, variables, and message formats to use.

It’s not surprising that Synopsys does not want to make this too easy. One goal of offering the Lynx flow is to encourage the use of an all Synopsys tool flow. If it were truly a wide open flow with easy addition of 3rd-party tools, then there would be less of a hook to use Synopsys tools. (Personally, I disagree with this approach and think Synopsys would be better off offering a truly open flow, but that’s the next post).

As a result, Lynx will be used only by customers using a predominantly Synopsys tool flow. I think that is OK by Synopsys. They’d rather sell a few less Lynx licenses rather than support the use of 3rd-party tools. Unfortunately for designers using other tools, Lynx does not currently have that much to offer.

2. Lynx Is Difficult To Upgrade

One of the complaints of Lynx’s predecessors is that it is not easy to upgrade from version to version. That is because it is a set of template scripts, not an installed flow. What do I mean?

When you create a project using Lynx, a set of template scripts are copied from a central area and configured for you based on your input. Let’s call this V1.0. As you go through the design process, you customize the flow by changing settings in the GUI, which in turn changes the local scripts that you copied from the central area. Now, let’s say that you want to upgrade to V1.1 because there are some bug fixes or new capabilities you need to use. You can’t do that easily. You have 2 alternatives:

  1. Create a new project using v1.1 and try to replicate any customizations from the v1.0 project in the v1.1 project. I hope you kept good notes.
  2. Diff the new scripts and the old scripts and then update your version 1.0 scripts to manually upgrade to v1.1.

Admittedly, Synopsys provides release notes that identify what has changed and that will help with approach #2. And they try to avoid making gratuitous variable name changes. Even then, the upgrade process is error-prone and manual. In most cases, for any one project, customers will just stick with the version of Lynx that they started with in order to avoid this mess. Then they’ll upgrade between projects. That negates the benefit of having a flow that is always “up-to-date”.

In my humble opinion, a better way to architect the flow would have been to have a set of global scripts that are untouchable and a set of local scripts that can be customized to override or supplement the global scripts. In that case, a new version of Lynx would replace the global scripts, but the local scripts, where all the customization is done, could remain unchanged.

3. Debugging Is Difficult

Have you ever tried to debug a set of scripts that someone else wrote? Even worse, scripts that are broken up into multiple scripts in multiple directories. Even worse, by looking at log files that do not echo directly what commands were executed. Even worse, you were told you never had to worry about the scripts in the first place. And worst of all, when you called for support, nobody knew what you were talking about.

That is what debugging was like in Pilot, Lynx’s most recent predecessor.

I’ve been told that Synopsys has tried to address these issues in Lynx. They now have a switch that will echo the commands to the log files. The Runtime Manager can supposedly locate the errors in the log files and correlate them to the scripts. And now that Lynx is a supported product, Support Center and ACs should know how to help. Still, I’d like to see it to believe it. From what I understand, many of these features are still a bit flakey and almost all the Synopsys consultants, the largest user base for the flow, do not use the new GUIs yet.


In summary, Lynx’s main weakness is that it was not originally architected as a forward compatible, open flow for novice tools users, which is what it is being positioned as. In fact, it started out as a set of scripts written by Avanti tool experts for Avanti tool experts to use with Avanti tools. Synopsys has done a lot to try to morph the flow into something that allows 3rd-party tools, upgrades more easily, and eases debug, but the inherent architecture limits what can be done.

So, what should have been added to make Lynx better? You’ll want to read the next in the series: The Missing Lynx.

Part 1 - Synopsys Lynx Design System Debuts at SNUG

Part 2 -  Lynx Design System? - It’s The Flow, Stupid!

Part 3 -  Strongest Lynx

Part 5 - The Mising Lynx - The ASIC Cloud

harry the ASIC guy

Strongest Lynx

Monday, March 23rd, 2009

I know. I know. I know.

I said that I was going to publish the final post in a 3-part series on Synopsys Lynx last Friday. However, as I put my notes together, I realized how much there is to say. So, I’m breaking up the last post into 3 separate posts: The Strongest Lynx, The Weakest Lynx, and The Missing Lynx (clever, huh?).  First, the Strongest Lynx.

I think that the best way to understand the strengths of Lynx is to consider who is Synopsys’ intended customer for this flow offering. After all, the offering is designed for them. In that regard, since adopting Synopsys Lynx is such a big change in methodology, Synopsys is looking for customers who are already planning some sort of major transition, including:

  • Startup companies who have no design flow to begin with
  • Companies making a significant transition to a new technology node or process (e.g. 90nm => 45nm)
  • Companies expanding their existing design capabilities (e.g. ASIC => COT)
  • Companies moving towards an all Synopsys flow (e.g. vendor consolidation)
  • Companies downsizing their in-house CAD teams

These companies are already committed to some sort of change in design flow, so Synopsys offers them a “buy” alternative to making it in-house. Synopsys Lynx is attractive to the extent that it accelerates that transition process and allows the design teams to be productive faster. In that light, the 3 greatest strength of Lynx seem to be:

1. 75-90% of a working design flow out-of-the-box.

I’m sure methodology experts and tool experts, if given a chance to dig into the Lynx scripts, would find areas to make improvements to the flow.  Nonetheless, I can say from experience managing teams using earlier versions (Tiger, Pilot), that Lynx provides a complete design flow that requires very little customization “out-of-the-box”. It is the same design flow that has evolved from almost 10 years of delivering design services and is being used by Synopsys’ own design services organization, so indeed they “eat their own dog food“. Synopsys says that they are doing more regression testing, which should increase quality. There is documentation and training, and Synopsys offers 1 week of on-site assistance to install and start customizing it.

2. A design flow that optimizes across the various tools.

It’s well understood that smaller process geometries require the various tools in the flow to work together more closely, exchanging data and anticipating what the other tools will do downstream. Synopsys claims to have implemented several such flows in Lynx, particularly highlighting their low-power flow. If this is true, that should result in better results than a point-tool approach.

3.  Ease-of-use features that help average tool users be productive more easily.

Design flows for very small geometries (65nm, 45nm, 32nm) are extremely complex and demand a depth of expertise across all the tools that is difficult to find. As a result, there is a need to simplify the design process and tool usage so “average” design teams can still implement these chips effectively. The Runtime Manager supposedly frees the designer from having to edit makefiles or tcl scripts, allowing control over all the appropriate variables through GUI settings and menus and debug of script errors through the GUI. Similarly, the Management Cockpit promises to provide valuable metrics without digging through log files and reports. If they deliver on these promises, the Runtime Manager and Management Cockpit will make average designers more productive more quickly. I have some doubts, though, especially since these GUIs are brand new and have not had extensive testing. I’d be interested to know if these run as smoothly as advertised or if there are issues getting them to deliver.

In summary, Lynx’s strength is in providing a 75-90% complete Synopsys design flow that optimizes across the tools to increase the design quality and provides graphical capabilities to make the flow easier to use for the average non-tool-expert designer. To my knowledge, none of the other major EDA vendors offer anything similar, either in scope or maturity.

If this sounds like an endorsement, you’ll want to read the next in the series : The Weakest Lynx.

Part 1 - Synopsys Lynx Design System Debuts at SNUG

Part 2 -  Lynx Design System? - It’s The Flow, Stupid!

Part 4 -  The Weakest Lynx

Part 5 - The Mising Lynx - The ASIC Cloud

harry the ASIC guy