Numbers don't lie: there is virtually no interest in high level synthesis

I finally read enough articles about high level synthesis (HLS) that give a sense of hype that just didn't seem to be matched by what I've heard. Now hype is pretty subjective, but numbers are not. For example, the High Level Synthesis group on LinkedIn only has 66 members (including myself!); compare that to the FPGA - Field Programmable Gate Array group which has 22,931 members (also including myself). If we were to suppose that HLS tools target FPGA users - which most tools (such as Vivado HLS, NEC CyberWorkbench, ImpulseC, etc.) do, and assuming that both FPGA users and HLS users have a LinkedIn account, then we might conclude from these numbers that less than 0.3% of FPGA users are interested in HLS.

These numbers are just an indication that there may be a different picture than painted by the various articles about HLS. Of course, you might argue that not everybody who's interested in a particular technology is necessarily a member on a group about this technology on a given social network, and you would be right. However, I think we can agree that pretty much everybody who's interested in a technology will search for it at some point. Let's see what we can dig about search patterns regarding HLS.

The graph below is a screenshot of Google Trends that plots the searches for FPGA (red and decreasing) and the searches for high level synthesis (blue, constant at just above zero). You can verify these results yourself, here is the query I used. Note how there is not enough search volume for Google to show us geographical information about these searches.

Interestingly, this seems to match the observation that there is virtually no interest among FPGA users about HLS. Results vary ever so slightly if you look for ASIC (use the "Application-Specific Integrated Circuit" topic rather than the "asic" keyword that matches a lot of things).

But perhaps this is because high level synthesis is such a new and innovative technology that we are still at the beginning of its adoption? But how can it be, when they claim 15 of the 20 top semiconductor companies rely on HLS? Enter the Diffusion of Innovations.

Diffusion of innovations

Diffusion of innovations is a framework that explains how innovations get adopted, and what makes the difference between the succesful adoption and failed adoption of an innovation.

Diffusion time

An important metric about the diffusion of an innovation is time. For example, the eponymous book shows how corn farmers in Iowa adopted hybrid seeds in the 1930s in nine years. Switching from a variety of corn to another variety requires experimentation, so the first farmers who wanted to adopt these new seeds planted them and had to wait for corn to grow, and probably repeated that experiment for a year or two. At this point you probably wonder where I'm going with this?

Well... High level synthesis (its modern form at least) is about 25 years old. You can check for it yourself, there was a tutorial on high level synthesis at EDAC 1991. Now if farmers have adopted new seeds in 9 years, but designers haven't adopted HLS in 25 years, there's little chance they will...

By the way, history shows that it is not until the innovators and early adopters have adopted an innovation that the real growth starts, see Crossing the Chasm for more details on how to move from early adoption to the mainstream. Now this crowd represents 16% of the total public, so there's room for growth from 0.3%!

So what about those 15 out of 20 top semiconductor companies?

First, it is a vendor of HLS software that claims that. This is the word used by the article I linked to above, not my own choice of word. Second, there are no numbers of how many designers in these companies actually use it in their daily lives. It has been known that some EDA companies have offered HLS licenses as part of larger deals to ease the adoption, counting these clients as adopters even if they don't use it.

Last but not least, big companies are seldom innovators/early adopters (for reasons that should be obvious). It could be a case of authoritative adoption, in other words management decides to adopt it, even if the designers themselves do not perceive any advantage in the technology!


Please comment below! Feel free to share numbers that you may have that corroborate this post; I also welcome numbers that contradict this post, good luck finding them though! :-)