Posts Tagged ‘functional verification’

7 May, 2014

My Feb. 4 post introduced Mentor Graphics’ three-step FPGA verification process intended to help design teams get out of the reprogrammable lab more effectively. Since then, I’ve engaged FPGA vendors, design managers and engineers to explain the process, paying special attention to the merits and technical detail for injecting automation into any FPGA verification environment, the hallmark of Mentor’s process. The feedback from these conversations helped me to develop a series of technical webinars, now available for free and on-demand. Check them out and let us know what you think in the comments below. My hope is the webinars might serve as a starting point for your own conversations on verification of FPGAs, demand for which seems to continue to grow as process nodes shrink.

Injecting Automation into Verification – FPGA Market Trends

Injecting Automation into Verification – Code Coverage

Injecting Automation into Verification – Assertions

Injecting Automation into Verification – Improved Throughput

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25 April, 2014

DVCon 2014 Conference Proceedings Published

2014DVCon_logoWith record attendance announced for DVCon 2014, one might wonder if there is really a need to put some of the “Accellera Day” tutorial videos online.  With more than 1,000 professionals attending in some capacity, it would be easy to conclude that everyone that needs to know about UVM and the developments on the updated version to it, probably know.  Looking at just the LinkedIn design and verification forums one will realize there are 10’s of thousands who would have benefited if they had attended DVCon.  Thus, sharing this information more broadly is in order.

UVM Tutorial Video

UVM – What’s Now and What’s Next” is the tittle of the DVCon 2014 tutorial on UVM.  It covered use cases and pragmatic topics of the current UVM 1.1 standard as well as advanced topics for the next update, UVM 1.2.  The presenters covered sequence creation, register layer use, TLM-based communication, test execution, run-time phases and messaging enhancements.

The tutorial was split into five separate sections delivered by five speakers as follows:

  • Working Group Update: Adam Sherer, Accellera (7 min.)
  • Overview and Library Concepts: John Aynsley, Doulos (36 min.)
  • Stimulus Generation: Shawn Honess, Synopsys (21 min.)
  • UVM Register Layer: Tom Fitzpatrick, Mentor Graphics (36 min.)
  • UVM 1.2 Introduction: Uwe Simm, Cadence Design Systems (25 min.)

You can find out more information about the online tutorial videos hereRegistration is required, but there is no charge for access.  Once you have registered, you will get links to each of the five sections.  You can stream them or download them for offline access as you wish.  They are suitable for viewing on your computer or mobile devices.

DVCon 2014 Proceedings

DVCon 2014 was a full conference; it was more than just the the Accellera Day UVM Tutorial.  And in keeping with DVCon tradition, the conference proceedings are made available to all several months after the conference without charge.  If you visit the DVCon history area, you will find the 2014 proceedings have been published.  What I like about the DVCon proceedings it not only are the papers published, but the slides that were presented at the conference will often accompany the paper.

As an example, if you were interested in the DVCon 2014 Best Oral Presentation paper and presentation (Kelly D. Larson from NVIDIA on , “Determining Test Quality through Dynamic Runtime Monitoring of SystemVerilog Assertions” by the way), you will now find both the paper and presentation available online here.

For all those who did not make it to DVCon 2014, or who were there and could not see everything, the proceedings are now online and the first of the Accellera Day tutorials videos is published. Accellera is busy readying its other tutorial videos.  I’ll share information on their availability as they appear in the weeks and months ahead.

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4 February, 2014

Marketing teams at FPGA vendors have been busy as the silicon nanometer geometry race escalates. Altera is “delivering the unimaginable” while Xilinx is offering “all programmable SoCs” to design centers. It’s clear that the SoC has become more accessible to a broader market today and that FPGA vendors have staked out a solid technology roadmap for the near future. Do marketing messages surrounding the geometry race effect day to day life of engineers, and if so, how – especially when it comes to verification?
An excellent whitepaper from Altera, “The Breakthrough Advantage for FPGAs with Tri-Gate Technology,” covers Altera’s Stratix 10 FPGAs and SoCs. The paper describes verification challenges in this new expanded market this way: “Although current generation FPGAs require a rigorous simulation verification methodology rivaling ASICs, the additional lab testing and ability to reprogram FPGAs save substantial manpower investment. The overall cost of ownership must be considered when comparing an FPGA whose component price is higher than an ASIC of similar complexity.” I believe you can use this statement to engage your management in a discussion about better verification processes.

Xilinx also has excellent published technical resources. Its recent UltraScale backgrounder describes how they are solving the challenges in implementing a design with their reprogrammable silicon. Clearly Xilinx has made an impressive investment to make it easier to implement a design with its FPGA UltraScale products. Improvements include ASIC-like clocking and annealing dataflow bottlenecks without compromising performance. Xilinx also describes improvements when using its Vivado design suite, particularly when it comes to in-lab design bring up.

For other FPGA insights, it’s also worth checking out Electronics Engineering Journal’s recent article “Proliferating Programmability in 2014,” which claims that the long-term future of FPGAs tool flows even though, as Kevin Morris sees it, EDA seems to have abandoned the market. (Kevin, I’m here to tell you you’re wrong.)

Do you think it’s inevitable that your FPGA team will first struggle to make it across the verification finish line before adopting a more process-oriented verification flow like the ASIC market demands? It’s not. I base this conclusion on the many conversations I’ve had with FPGA designers, their managers, sales engineers and many other talented people in this market over the years. Yes, there are significant challenges in FPGA design, but not all of them are technology related. With some emotion, one engineer remarked that debugging the same type of issue over and over in the hardware lab and expecting a different outcome was insane. (He’s right.) Others say they need specific ROI information for their management to even accept their need for change. Still others state that had they only known the solutions I talked about in my seminar a year ago, they would have not spent months and months bringing up their design in the lab.
With my peers here at Mentor Graphics, I have developed a three-step verification flow that includes coverage, assertions and improved throughput. I’ll write about this flow and related issues in the weeks ahead here on this blog. The flow is built on fundamental verification technologies that benefit the broad FPGA market. The goal, in developing the technology and writing about it here, has been to provide practical solutions and help more FPGA teams cross the verification gap.

In the meantime, what are your stories? Are you able to influence your management into adopting advanced technology to aid lab bring-up? Is your management’s bias towards lower cost and faster implementation (at the expense of verification)? Let me know in the comments or, if you prefer, by e-mail: joe_rodriguez@mentor.com.

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30 October, 2013

MENTOR GRAPHICS AT ARM TECHCON

This week ARM® TechCon® 2013 is being held at the Santa Clara Convention Center from Tuesday October 29 through Thursday October 31st, but don’t worry, there’s nothing to be scared about.  The theme is “Where Intelligence Counts”, and in fact as a platinum sponsor of the event, Mentor Graphics is excited to present no less than ten technical and training sessions about using intelligent technology to design and verify ARM-based designs.

My personal favorite is scheduled for Halloween Day at 1:30pm, where I’ll tell you about a trick that Altera used to shave several months off their schedule, while verifying the functionality and performance of an ARM AXI™ fabric interconnect subsystem.  And the real treat is that they achieved first silicon success as well.  In keeping with the event’s theme, they used something called “intelligent” testbench automation.

And whether you’re designing multi-core designs with AXI fabrics, wireless designs with AMBA® 4 ACE™ extensions, or even enterprise computing systems with ARM’s latest AMBA® 5 CHI™ architecture, these sessions show you how to take advantage of the very latest simulation and formal technology to verify SoC connectivity, ensure correct interconnect functional operation, and even analyze on-chip network performance.

On Tuesday at 10:30am, Gordon Allan described how an intelligent performance analysis solution can leverage the power of an SQL database to analyze and verify interconnect performance in ways that traditional verification techniques cannot.  He showed a wide range of dynamic visual representations produced by SoC regressions that can be quickly and easily manipulated by engineers to verify performance to avoid expensive overdesign.

Right after Gordon’s session, Ping Yeung discussed using intelligent formal verification to automate SoC connectivity, overcoming observability and controllability challenges faced by simulation-only solutions.  Formal verification can examine all possible scenarios exhaustively, verifying on-chip bus connectivity, pin multiplexing of constrained interfaces, connectivity of clock and reset signals, as well as power control and scan test signal connectivity.

On Wednesday, Mark Peryer shows how to verify AMBA interconnect performance using intelligent database analysis and intelligent testbench automation for traffic scenario generation.  These techniques enable automatic testbench instrumentation for configurable ARM-based interconnect subsystems, as well as highly-efficient dense, medium, sparse, and varied bus traffic generation that covers even the most difficult to achieve corner-case conditions.

And finally also on Halloween, Andy Meyer offers an intelligent workshop for those that are designing high performance systems with hierarchical and distributed caches, using either ARM’s AMBA 5 CHI architecture or ARM’s AMBA 4 ACE architecture.  He’ll cover topics including how caching works, how to improve caching performance, and how to verify cache coherency.

For more information about these sessions, be sure to visit the ARM TechCon program website.  Or if you miss any of them, and would like to learn about how this intelligent technology can help you verify your ARM designs, don’t be afraid to email me at mark_olen@mentor.com.   Happy Halloween!

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19 August, 2013

Verification Techniques & Technologies Adoption Trends

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (for background on the study, click here).

In my previous blog (Part 9 click here), I focused on some of the 2012 Wilson Research Group findings related to design and verification language and library trends. In this blog, I present verification techniques and technologies adoption trends, as identified by the 2012 Wilson Research Group study.

An interesting trend we are starting to see is that the electronic industry is maturing its functional verification processes, whether they are targeting their designs at IC/ASIC or FPGA implementations. This blog provides data to support this claim. An interesting question you might ask is, “What is driving this trend?” In some of my earlier blogs (click here for Part 1 and Part 2) I showed an that design complexity is increasing in terms design sizes and number of embedded processors. In addition, I’ve presented trend data that showed an increase in total project time and effort spent in verification (click here for Part 5 and Part 6). My belief is that the industry is being forced to mature its functional verification processes to address increasing complexity and effort.

Simulation Techniques Adoption Trends

Let’s begin by comparing  non-FPGA adoption trends related to various simulation techniques from the 2007 Far West Research study  (in blue) with the 2012 Wilson Research Group study  (in green), as shown in Figure 1.

Figure 1. Simulation-based technique adoption trends for non-FPGA designs

You can see that the study finds the industry increasing its adoption of various functional verification techniques for non-FPGA targeted designs. Clearly the industry is maturing its processes as I previously claimed.

For example, in 2007, the Far West Research Group found that only 48 percent of the industry performed code coverage. This surprised me. After all, HDL-based code coverage is a technology that has been around since the early 1990’s. However, I did informally verify the 2007 results through numerous customer visits and discussions. In 2012, we see that the industry adoption of code coverage has increased to 70 percent.

In 2007, the Far West Research Group study found that 37 percent of the industry had adopted assertions for use in simulation. In 2012, we find that industry adoption of assertions had increased to 63 percent. I believe that the maturing of the various assertion language standards has contributed to this increased adoption.

In 2007, the Far West Research Group study found that 40 percent of the industry had adopted functional coverage for use in simulation. In 2010, the industry adoption of functional coverage had increased to 66 percent. Part of this increase in functional coverage adoption has been driven by the increased adoption of constrained-random simulation, since you really can’t effectively do constrained-random simulation without doing functional coverage.

Now let’s look at  FPGA adoption trends related to various simulation techniques from the 2010 Far West Research study  (in pink) with the 2012 Wilson Research Group study  (in red).

Figure 2. Simulation-based technique adoption trends for non-FPGA designs

Again, you can clearly see that the industry is increasing its adoption of various functional verification techniques for FPGA targeted designs. This past year I have spent a significant amount of time in discussions with FPGA project managers around the world. During these discussions, most mangers mention the drive to improve verification process within their projects due to  rising complexity of this class of designs. The Wilson Research Group data supports these claims.

In fact, Figure 3 illustrates this maturing trend in the FPGA space, where we saw a 15 percent increase in the adoption of RTL simulation and an 8.5 percent increase in the adoption of code coverage. For complex FPGA designs, the traditional approach of “burn and churn” and debug in the lab is no longer a viable option. Nonetheless, it is still somewhat alarming that 31 percent of the FPGA study participants work on projects that perform no RTL simulation.

Figure 3. FPGA projects maturing their verification processes

Signoff Criteria Trends

We saw earlier in this blog the increased adoption of coverage techniques in the industry. Coverage has become a major component of a project’s verification signoff criteria. In Figure 4, we see how coverage has increased in importance in verification signoff criteria within the past five years, while other decision attributes have declined in terms of importance.

Figure 4. Non-FPGA functional verification signoff criteria trends

We see the same trends for FPGA designs, as shown in Figure 5.

Figure 5. FPGA functional verification signoff criteria trends

In my next blog (click here), I plan to continue the discussion related to adoption of various verification technologies and techniques as identified by the 2012 Wilson Research Group study.

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12 August, 2013

Language and Library Trends (Continued)

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (for a background on the study, click here).

In my previous blog (Part 8 click here), I focused on design and verification language trends, as identified by the Wilson Research Group study. This blog presents additional trends related to verification language and library adoption trends.

You might note that for some of the language and library data I present, the percentage sums to more than 100 percent. The reason for this is that some participants’ projects use multiple languages or multiple testbench methodologies.

Testbench Methodology Class Library Adoption

Now let’s look at testbench methodology and class library adoption for IC/ASIC designs. Figure 1 shows the trends in terms of methodology and class library adoption by comparing the 2010 Wilson Research Group study (in blue) with the 2012 study (in green). Today, we see a downward trend in terms of adoption of all testbench methodologies and class libraries with the exception of UVM, which has increased by 486 percent since the fall of 2010. The study participants were also asked what they plan to use within the next 12 months, and based on the responses, UVM is projected to increase an additional 46 percent.

Figure 1. Methodology and class library trends

Figure 2 show the adoption of testbench methodologies and class libraries for FPGA designs (in red). We do not have sufficient data to show prior adoption trends in the FPGA space, but we anticipate that our future studies will enable us to do this. However, we did ask the FPGA study participants which testbench methodologies and class libraries they were planning to adopt within the next 12 months. Based on these responses, we anticipate that UVM adoption will increase by 40 percent, and OVM increase by 24 percent in the FPGA space.

Figure 2. Methodology and class library trends

Assertion Languages and Libraries

Finally, let’s examine assertion language and library adoption for IC/ASIC designs. The Wilson Research Group study found that 63 percent of all the IC/ASIC participants have adopted assertion-based verification (ABV) as part of their verification strategy. The data presented in this section shows the assertion language and library adoption trend related to those participants who have adopted ABV.

Figure 3 shows the trends in terms of assertion language and library adoption by comparing the 2010 Wilson Research Group study (in blue), the 2012 Wilson Research Group study (in green), and the projected adoption trends within the next 12 months (in purple). The adoption of SVA continues to increase, while other assertion languages and libraries either remain flat or decline.

Figure 3. Assertion language and library adoption for Non-FPGA designs

Figure 4 shows the adoption of assertion language trends for FPGA designs (in red). Again, we do not have sufficient data to show prior adoption trends in the FPGA space, but we anticipate that our future studies will enable us to do this. We did ask the FPGA study participants which assertion languages and libraries they planned to adopt within the next 12 months. Based on these responses, we anticipate an increase in adoption for OVL, SVA, and PSL in the FPGA space within the next 12 months.

Figure 4. Trends in assertion language and library adoption for FPGA designs

In my next blog (click here), I plan to focus on the adoption of various verification technologies and techniques used in the industry, as identified by the 2012 Wilson Research Group study.

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5 August, 2013

Language and Library Trends

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (for a background on the study, click here).

In my previous blog (Part 7 click here), I focused on some of the 2012 Wilson Research Group findings related to testbench characteristics and simulation strategies. In this blog, I present design and verification language trends, as identified by the Wilson Research Group study.

You might note that for some of the language and library data I present, the percentage sums to more than one hundred percent. The reason for this is that some participants’ projects use multiple languages.

RTL Design Languages

Let’s begin by examining the languages used for RTL design. Figure 1 shows the trends in terms of languages used for design, by comparing the 2007 Far West Research study (in gray), the 2010 Wilson Research Group study (in blue), the 2012 Wilson Research Group study (in green), as well as the projected design language adoption trends within the next twelve months (in purple) as identified by the study participants. Note that the design language adoption is declining for most of the languages with the exception of SystemVerilog whose adoption continues to increase.

Also, it’s important to note that this study focused on languages used for RTL design. We have conducted a few informal studies related to languages used for architectural modeling—and it’s not too big of a surprise that we see increased adoption of C/C++ and SystemC in that space. However, since those studies have (thus far) been informal and not as rigorously executed as the Wilson Research Group study, I have decided to withhold that data until a more formal blind study can be executed related to architectural modeling and virtual prototyping.

Figure 1. Trends in languages used for Non-FPGA design

Let’s now look at the languages used specifically for FPGA RTL design. Figure 2 shows the trends in terms of languages used for FPGA design, by comparing the 2012 Wilson Research Group study (in red) with the projected design language adoption trends within the next twelve months (in purple).

Figure 2. Languages used for Non-FPGA design

It’s not too big of a surprise that VHDL is the predominant language used for FPGA RTL design, although we are starting to see increased interest in SystemVerilog.

Verification Languages

Next, let’s look at the languages used to verify Non-FPGA designs (that is, languages used to create simulation testbenches). Figure 3 shows the trends in terms of languages used to create simulation testbenches by comparing the 2007 Far West Research study (in gray), the 2010 Wilson Research Group study (in blue), and the 2012 Wilson Research Group study (in green).

Figure 3. Trends in languages used in verification to create Non-FPGA simulation testbenches

The study revealed that verification language adoption is declining for most of the languages with the exception of SystemVerilog whose adoption is increasing. In fact, SystemVerilog adoption increased by 8.3 percent between 2010 and 2012.

Figure 4 provides a different analysis of the data by partitioning the projects by design size, and then calculating the adoption of SystemVerilog for creating testbenches by size. The design size partitions are represented as: less than 5M gates, 5M to 20M gates, and greater than 20M gates. Obviously, we find that the larger the design size, the greater the adoption of SystemVerilog for creating testbenches. Yet, probably the most interesting observation we can make from examining Figure 4 is related to smaller designs that are less than 5M gates. Here we see that 58.8 percent of the industry has adopted SystemVerilog for verification. In other words, it is safe to say that SystemVerilog for verification has become mainstream today and not just limited to early adopters or leading-edge design projects.

Figure 4. SystemVerilog (for verification) adoption by design size

Let’s now look at the languages used specifically for FPGA RTL design. Figure 5 shows the trends in terms of languages used for FPGA design, by comparing the 2012 Wilson Research Group study (in red) with the projected design language adoption trends within the next twelve months (in purple).

Figure 5. Trends in languages used in verification to create FPGA simulation testbenches

In my next blog (click here), I’ll continue the discussion on design and verification language trends as revealed by the 2012 Wilson Research Group Functional Verification Study.

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29 July, 2013

Testbench Characteristics and Simulation Strategies

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (for background on the study, click here).

In my previous blog (click here), I focused on the controversial topic of effort spent in verification. In this blog, I focus on some of the 2012 Wilson Research Group findings related to testbench characteristics and simulation strategies. Although I am shifting the focus away from verification effort, I believe that the data I present in this blog is related to my previous blog and really needs to be considered when calculating effort.

Time Spent in full-chip versus Subsystem-Level Simulation

Let’s begin by looking at Figure 1, which shows the percentage of time (on average) that a project spends in full-chip or SoC integration-level verification versus subsystem and IP block-level verification. The mean time performing full chip verification is represented by the dark green bar, while the mean time performing subsystem verification is represented by the light green bar. Keep in mind that this graph represents the industry average. Some projects spend more time in full-chip verification, while other projects spend less time.

Figure 1. Mean time spent in full chip versus subsystem simulation

Number of Tests Created to Verify the Design in Simulation

Next, let’s look at Figure 2, which shows the number of tests various projects create to verify their designs using simulation. The graph represents the findings from the 2007 Far West Research study (in gray), the 2010 Wilson Research Group study (in blue), and the 2012 Wilson Research Group study (in green). Note that the curves look remarkably similar over the past five years. The median number of tests created to verify the design is within the range of (>200 – 500) tests. It is interesting to see a sharp percentage increase in the number of participants who claimed that fewer tests (1 – 100) were created to verify a design in 2012. It’s hard to determine exactly why this was the case—perhaps it is due to the increased use of constrained random (which I will talk about shortly). Or perhaps there has been an increased use of legacy tests. The study was not design to go deeper into this issue and try to uncover the root cause. This is something I intend to informally study this next year through discussions with various industry thought leaders.

Figure 2. Number of tests created to verify a design in simulation

Percentage of Directed Tests versus Constrained-Random Tests

Now let’s compare the percentage of directed testing that is performed on a project to the percentage of constrained-random testing. Of course, in reality there is a wide range in the amount of directed and constrained-random testing that is actually performed on various projects. For example, some projects spend all of their time doing directed testing, while other projects combine techniques and spend part of their time doing directed testing—and the other part doing constrained-random. For our comparison, we will look at the industry average, as shown in Figure 3. The average percentage of tests that were directed is represented by the dark green bar, while the average percentage of tests that are constrained-random is represented by the light green bar.

Figure 3. Mean directed versus constrained-random testing performed on a project

Notice how the percentage mix of directed versus constrained-random testing has changed over the past two years.Today we see that, on average, a project performs more constrained-random simulation. In fact, between 2010 and 2012 there has been a 39 percent increase in the use of constrained-random simulation on a project. One driving force behind this increase has been the maturing and acceptance of both the SystemVerilog and UVM standards—since two standards facilitate an easier implementation of a constrained-random testbench. In addition, today we find that an entire ecosystem has emerged around both the SystemVerilog and UVM standards. This ecosystem consists of tools, verification IP, and industry expertise, such as consulting and training.

Nonetheless, even with the increased adoption of constrained-random simulation on a project, you will find that constrained-random simulation is generally only performed at the IP block or subsystem level. For the full SoC level simulation, directed testing and processor-driven verification are the prominent simulation-based techniques in use today.

Simulation Regression Time

Now let’s look at the time that various projects spend in a simulation regression. Figure 4 shows the trends in terms of simulation regression time by comparing the 2007 Far West Research study (in gray) with the 2010 Wilson Research Group study (in blue), and the 2012 Wilson Research Group study (in green). There really hasn’t been a significant change in the time spent in a simulation regression within the past three years. You will find that some teams spend days or even weeks in a regression. Yet today, the industry median is between 8 and 16 hours, and for many projects, there has been a decrease in regression time over the past few years. Of course, this is another example of where deeper analysis is required to truly understand what is going on. To begin with, these questions should probably be refined to better understand simulation times related to IP versus SoC integration-level regressions. We will likely do that in future studies—with the understanding that we will not be able to show trends (or at least not initially).

Figure 4. Simulation regression time trends

In my next blog (click here), I’ll focus on design and verification language trends, as identified by the 2012 Wilson Research Group study.

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22 July, 2013

Effort Spent On Verification (Continued)

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (for a background on the study, click here).

In my previous blog (click here), I focused on the controversial topic of effort spent in verification. This blog continues that discussion.

I stated in my previous blog that I don’t believe there is a simple answer to the question, “how much effort was spent on verification in your last project?” I believe that it is necessary to look at multiple data points to truly get a sense of the real effort involved in verification today. So, let’s look at a few additional findings from the study.

Time designers spend in verification

It’s important to note that verification engineers are not the only project members involved in functional verification. Design engineers spend a significant amount of their time in verification too, as shown in Figure 1.

Figure 1. Average (mean) time design engineers spend in design vs. verification

In fact, you might note that design engineers now actually spend more time doing verification than design. This time expenditure has shifted in the last five years. In fact, the amount of time that design engineers spend doing verification has increased by 15 percent since 2007, while the amount of time they spend doing design has decreased by about 13 percent.

The designer’s involvement in verification ranges from:

  • Small sandbox testing to explore various aspects of the implementation
  • Full functional testing of IP blocks and SoC integration
  • Debugging verification problems identified by a separate verification team

Percentage of time verification engineers spends in various task

Next, let’s look at the mean time verification engineers spend in performing various tasks related to their specific project. You might note that verification engineers spend most of their time in debugging. Ideally, if all the tasks were optimized, then you would expect this. Yet, unfortunately, the time spent in debugging can vary significantly from project-to-project, which presents scheduling challenges for managers during a project’s verification planning process.

Figure 2. Average (mean) time verification engineers spend in various task

Number of formal analysis, FPGA prototyping, and emulation Engineers

Functional verification is not limited to simulation-based techniques. Hence, it’s important to gather data related to other functional verification techniques, such as the number of verification engineers involved in formal analysis, FPGA prototyping, and emulation.

Figure 3 presents the trends in terms of the number of verification engineers focused on formal analysis on a project. In 2007, the mean number of verification engineers focused on formal analysis on a project was 1.68, while in 2010 the mean number increased to 1.84. For some reason, we did see a slight decreased in the mean number of verification engineers who focus on formal in 2012. Regardless, the curve is remarkably consistent for the past five years.

Figure 3. Median number of verification engineers focused on formal analysis

Although FPGA prototyping is a common technique used to create platforms for software development, it is also sometimes used by projects for SoC integration verification and system validation. Figure 4 presents the trends in terms of the number of verification engineers focused on FPGA prototyping. In 2007, the mean number of verification engineers focused on FPGA prototyping on a project was 1.42, while in 2010 the mean number was 1.86. In 2012 we saw a slight decline in mean number of verification engineers focused on FPGA prototyping. However, the curve has been remarkably similar for the past five years.

Figure 4. Number of verification engineers focused on FPGA prototyping

Figure 5 presents the trends in terms of the number of verification engineers focused on hardware-assisted acceleration and emulation. In 2007, the mean number of verification engineers focused on hardware-assisted acceleration and emulation on a project was 1.31, while in 2010 the mean number was 1.86. In 2012, we see a slight decrease in the mean number of verification engineers who focus on hardware-assisted acceleration and emulation.

Figure 5. Number of verification engineers focused on emulation

Again, noticed how the curve has been consistent over the past five years. In other words, we are not seeing any big trends in terms of increased verification engineers focused predominately on formal, FPGA prototyping, and hardware-assisted acceleration and emulation. This trend was certainly not true for general verification engineers who focus on simulation-based techniques, as I presented in my previous blog, where we saw a 75 percent increase in the peak number verification engineers involved on a project within the past five years.

A few more thoughts on verification effort

So, can I conclusively state that 70 percent of a project’s effort is spent in verification today as some people have claimed? No. In fact, even after reviewing the data on different aspects of today’s verification process, I would still find it difficult to state quantitatively what the effort is. Yet, the data that I’ve presented so far seems to indicate that the effort (whatever it is) is increasing. And there is still additional data relevant to the verification effort discussion that I plan to present in upcoming blogs. However, in my next blog (click here), I shift the discussion from verification effort, and focus on some of the 2012 Wilson Research Group findings related to testbench characteristics and simulation strategies.

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15 July, 2013

 

Effort Spent in Verification

This blog is a continuation of a series of blogs that present the highlights from the 2012 Wilson Research Group Functional Verification Study (click here). In my previous blog (click here), I focused on design and verification reuse trends. In this blog, I focus on the controversial topic of the amount of effort spent in verification.

Directly asking study participants how much effort they spend in verification will not work. The reason is that it’s hard to find a paper or article on verification that doesn’t start with the phrase: “Seventy percent of a project’s effort is spent in verification…” In other words, the industry is already biased to respond with this effort value. Yet, there are really no creditable references to quantify this value.

I don’t believe that there is a simple answer to the question, “How much effort was spent on verification in your last project?” In fact, I believe that it is necessary to look at multiple data points derived from multiple questions to truly get a sense of effort spent in verification. And that’s what we did in our functional verification study.

Total Project Time Spent in Verification

To try to assess the effort spent in verification, let’s begin by looking at one data point, which is the total project time spent in verification. Figure 1 shows the trends in total percentage of project time spent in verification for non-FPGA designs by comparing the 2007 Far West Research study (in gray), the 2010 Wilson Research Group study (in blue), and the 2012 Wilson Research Group study (in green). 

Figure 1. Percentage of total project time spent in verification for Non-FPGA designs

The graph clearly shows that there are some projects that spend a significant percentage of project time in verification (>80%), while other projects spend significantly less time. Notice that in 2007, the average (mean) project time spent in verification was 49 percent, while the average increased to 56 percent in 2010 and remained the same in 2012.

Figure 2 shows the trends in total percentage of project time spent in verification for FPGA designs by comparing the 2010 Wilson Research Group study (in pink) and the 2012 Wilson Research Group study (in red).

 

Figure 2. Percentage of total project time spent in verification for FPGA designs

You might note that many FPGA projects tend to spend less time in verification than non-FPGA projects. Traditionally, the strategy for FPGA designs has been to get to the lab as soon as possible and debug issues in the lab. In a future blog I’ll show data that indicates this strategy does not necessarily yield good results in terms of meeting project schedule or quality objectives.

Peak Number of Design and Verification Engineers

Next, let’s look at another data point, the average (mean) peak number of engineers involved on a project. Figure 4 compares the growth in recent years for the average peak number of design engineers (in light green) and verification engineers (in dark green) working on a typical non-FPGA project.

 

Figure 3. Peak number of design vs. verification engineer trends for non-FPGA projects

Note that there has not been a significant increase in design engineers in the past five years, although design sizes have continued to increase at a Moore’s Law rate. This is partially due to increased adoption of internal and external IP (as I discussed in my previous blog) as well as continued productivity improvements due to automation.

However, the mean peak number of verification engineers working on non-FPGA projects has increased by 75% within the last five years. In fact, today we see (on average) a one-to-one ratio for a project’s peak number of design and verification engineers.

Figure 4 provides a different analysis of the data by partitioning the projects by design sizes, and then calculating the mean peak number of verification engineers by project design. The design size partitions are represented as: less than 5M gates, 5M to 20M gates, and greater than 20M gates.

 

Figure 4. Mean peak number of verification engineer trends by design size for non-FPGA projects

Figure 5 shows the average (mean) peak number of design engineers (in red) and verification engineers (in pink) working on a typical FPGA project.

 

Figure 5. Peak number of design vs. verification engineer trends for non-FPGA projects 

Also, note that the ratio of design engineers versus verification engineers hasn’t changed within the last two years for FPGA projects. Typically, design engineers on FPGA projects are responsible for verification too, and you will find many projects that do not have verification engineers. This trend, however, will likely change as FPGA designs become more complex. We are already seeing this on some very complex FPGA projects today.

In my next blog (click here), I’ll continue the discussion on effort spent in verification as revealed by the 2012 Wilson Research Group Functional Verification Study.

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