Posts Tagged ‘Synplify’

Synopsys Synphony Synopsis

Monday, October 12th, 2009

sheet_music.jpgI was contacted a few weeks ago by Synopsys’ PR agency to see if I’d be interested in covering an upcoming product announcement. I usually ignore these “opportunities” since the information provided is usually carefully wordsmithed marketing gobbledygook and not enough for me to really form an opinion. However, it turned out that this announcement was on a subject I know a little bit about, so I took them up on their offer.

The announcement was “embargoed“, that is, I was not to make it public until today. Embargoes are a vestige of the days when traditional journalism ruled the roost and when PR departments thought they could control the timing of their message. I don’t think embargoes benefit companies anymore since news is reported at light speed (literally) and people will write what they want when they want. Still, I consider it a sort of gentleman’s agreement so I’m not writing about it until today.

I also waited a little bit until the “mainstream press” wrote their articles. That let’s me point you to the best of them and conserve the space here for my own views, rather that regurgitating the press release and nuts and bolts.

(Update: Here is a very good description of the Synphony flow from Ron Wilson).

Today, Synopsys announced a new product called Synphony High Level Synthesis. You can read about this here. Basically, Synopsys is introducing a high level synthesis (aka behavioral synthesis) product that takes as its input Matlab M-Code and produces RTL Code, a cycle accurate C-model, and a testbench for simulation. Since I have not used the tool, I cannot comment on the capabilities or the quality of results or compare it to other tools on the market. However, I have had some past experience with tools like Matlab (specifically SPW) and Synphony (specifically Behavioral Compiler). So, here are my thoughts, observations, opinions that come to mind.

  1. Synopsys, once the leader in behavioral synthesis, is now the follower - When Synopsys introduced Behavioral Compiler over a decade ago they were the first to preach the gospel of high-level synthesis and all the associated benefits. Architectural optimization. Faster simulation. Bridging the gap between system design and ASIC design. Smaller and easier to understand code. Dogs and cats living together. The promises never fully materialized and Synopsys seemingly moved out of the market. Meanwhile, Mentor introduced Catapult C, Cadence introduced C-to-Silicon, and several others including Forte, Agility, Bluespec, Synfora, ChipVision, and AutoESL introduced their own high-level synthesis tools. Now, after acquiring Synplify DSP through Synplicity, Synopsys is finally re-entering the market (at least for ASIC design) with Synphony. The hunted have become the hunters.
  2. Synphony takes M-code from Matlab as its only source - Whereas most (but not all) other high-level synthesis tools input C like languages, Synopsys has chosen to input M-code only, at least for now. According to Chris Eddington, who is Director of Product Marketing for System-Level Products at Synopsys (according to his LinkedIn profile), approximately 60% of those who say they do “high-level design” are using M-code or some form of C (ANSI C, C++, System-C) for some portion of their design activities. Of those, slightly more use the C variants than M-code, which means that somewhere close to 25% of all ASIC designers could be a possible market for this tool.
  3. Synopsys can try to leverage the Matlab installed base - As mentioned above, Synopsys estimates that 25% of high-level designers could use the Synphony tool which is a pretty big market. By targeting mainly algorithmic design, not control logic, Synopsys can try to serve the Matlab installed base with a more narrowly targeted offering which should make it easier to support. It also allows Synopsys to avoid a bloody battle over C dominance and to pursue a blue ocean strategy with Matlab’s installed base. Interestingly though, there is no partnership with MathWorks implied by this announcement.
  4. Synphony leverages existing IP libraries - Libraries already exist for many common functions that were available for the Synplify DSP tool. The library elements are available as well for Synphony, allowing the designer to specify his functionality using this library or using M-code as the source.
  5. An FPGA tool is being adapted for ASIC - This is probably one of the first times that a tool initially developed for FPGAs (Synplify DSP) is being adapted for ASICs. It’s usually the other way around (e.g. FPGA Compiler grew out of Design Compiler). It should be interesting to see if the FPGA tool can “cut-it” in the ASIC world.
  6. Ties to implementation are seemingly tenuous - A tool that can take M-code as its input and produce RTL and C and do all the other things is all fine and good. But for Synphony to become more than an experimentation tool, it has to produce results (speed, area, power) as good or better than hand-coded RTL. However, the ties to the implementation tool (Design Compiler) are not as direct as even Behavioral Compiler was a decade ago. It seems that Synphony takes an approach where it pre-compiles and estimates timing for various blocks (kind of like building DesignWare libraries), but it assembles the design outside of DesignCompiler without all the associated timing views and engines necessary for true design and timing closure. It’s hard to understand how this can reliably produce results that consistently meet timing, but perhaps there is something that I am not aware of?
  7. Focus on “algorithmic design”, not control - As mentioned above, Synopsys is going after the folks using Matlab. And those designers are developing algorithms, not state machines. In essence, Synphony can focus on the fairly straightforward problem of scheduling mathematical operations to hit throughput and latency goals and not deal with more complex control logic. Much simpler.
  8. Conversion from Floating Point to Fixed Point - Anyone who has designed a filter or any DSP function knows that the devil is in the details, specifically the details of fixed point bit width. One choice of bit width affects downstream choices. You have to decide whether to round or truncate and these decisions can introduce unexpected artifacts into your signal. Synphony converts the floating point Matlab model into a fixed point implementation. Supposedly, it then allows you to easily fiddle with the bit widths to tweak the performance. Some earlier Synopsys products did this (Cossap, System Studio) and it’s a nice feature that can save time. We’ll see how useful it really is over time.
  9. Synphony produces real RTL, as well as C-code and a testbench - One of the drawbacks of Behavioral Compiler is that it never produced a human readable form of RTL code. This made it hard to simulate and debug the RTL. Synphony supplies readable RTL (or so I am told) as well as cycle accurate C-code for system simulation and a testbench for block simulation. This should help facilitate full chip simulations for chip integration, since Synphony will probably only be used on blocks, not entire chips.
  10. Couldn’t Synopsys come up with a better reference than Toyon Research Corporation - No offense to Toyon, but they are hardly a household name. It makes me wonder how many partners Synopsys has engaged in this development and how well tested this flow is. Not saying it isn’t well tested, just that Synopsys is making me wonder. Gimme a name I’ve heard of, please.

Only time will tell if Synphony is truly music to our ears, or if it is just SYNthesis that is PHONY.

harry the ASIC guy