A Portable Stimulus tool can do much of the work and allow many tests to be created based on the defined verification objectives.
For those who want all the answers now, Accellera recorded this DVCon training session that goes over the basics of the language and how tools work. I use many of the same examples for continuity purposes, but I will present the material in a different manner.
The Accellera tutorial starts off by defining the syntax of the language. I will concentrate on the abstract notions first and then get into syntax later. You will also read new or unfamiliar terms being thrown around such as declarative, partial specification, inference. I will get to all of that in due course; just don’t worry about the terms to start off with.
With the release of the 1.0 version of the Portable Stimulus Standard (PSS), the industry now has a solid base on which to build solutions and to ensure that the time and investment made by users to create verification intent models is portable. This should allow them to assess tools and decide which one fits their requirements best and which ones will fulfill their roadmap into the future. Unfortunately, it is not quite as easy as that, because many users have already moved beyond the basics as represented in the standard.
Committee members are taking a well-earned rest after working on this for three years. But we cannot afford to rest too long. The 1.0 release was not the end of the road –– it was merely the on-ramp toward a long road ahead. A lot is missing from the standard.
The industry waits with bated breath for the Accellera board to approve the Portable Stimulus 1.0 specification. It has been a long and arduous process over the past four years to get to this point, a process that most people never get to experience. This was my first standard, and to say it was an eye opener is somewhat of an understatement. In this blog, I am not going to dwell on the many bruises I suffered or the technical discussions that often seemed like personal attacks. Instead, I want to make the industry aware of some of the difficulties associated with bringing a new and somewhat revolutionary standard to market.
Breker has been making tools in this space for more than a decade and that presents the first, and very scary, hurdle for a startup company. For most of the period, before the creation of the standards group and throughout its development, we only had one major competitor and they were a much larger company than we were. Would getting the standards process going help us or hinder us?
https://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.png00Adnan Hamidhttps://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.pngAdnan Hamid2018-06-21 10:40:192020-02-07 21:05:26The Making of a Standard
Listening to users is never a bad thing. Users are the people who set Breker along its current direction and during the process of standardizing Portable Stimulus (PS), the ability to talk to an expanded group of users allowed Breker to see a larger portion of the total available market. We learned a lot.
Another group of people are starting to get interested in Portable Stimulus. These are industry consultants who help with methodology insertion and getting the industry up to speed. While not huge in number, these people have something that few others have to offer – a broad view of the market. They have seen more design styles and types of design than would exist within a single company.
DVCon is a great place to talk to design and verification engineers. As the Accellera Portable Stimulus Standard (PSS) gets closer to reality, we were able to share with them during the conference the progress made and the ways in which it may impact their task. Most of them are as excited about PSS as we are. While we have been working in this field for more than a decade and have received a lot of feedback, there are now many more people becoming aware of it and the potential that it has. This provides us with the opportunity to learn as well.
https://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.png00Adnan Hamidhttps://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.pngAdnan Hamid2018-03-15 20:38:032020-02-06 02:53:27Industry Struggles with System Coverage
When the forebears of SystemVerilog and UVM were being created, the world was a different place. Verification was primarily directed testing and code coverage was good enough to signal completion. Development of directed tests was getting to be slow, cumbersome and difficult to maintain. Languages and tools were created that added the ability to randomize stimulus but that created two problems. First, you had no idea what a test had accomplished and second, you had no idea that the design had actually reacted in the right manner. Thus, two additional models became necessary: a combination of checkers and scoreboard and the coverage model. The big problem was, and remains, that the three models are independent models only unified by a thin layer of syntax.
https://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.png00Adnan Hamidhttps://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.pngAdnan Hamid2018-02-22 20:42:042020-10-28 22:57:36UVM is Dead! Long live UVM+PS!
One of the great things associated with the development of a standard, such as the Portable Stimulus Standard (PSS), is that it brings together various stakeholders – often a broader selection of people than any single company did business with. When you initially develop a product you gear it toward a particular problem, one that you have some familiarity with. The resulting product attracts engineers who resonate with the product and they provide valuable feedback. This in turn helps to make the product more attractive to engineers with a similar need. If you are not careful, you can have a product that targets a narrow part of the market and that is all you learn to explore. It is the Innovators Dilemma, and can stop a company from developing a general purpose product.
https://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.png00Adnan Hamidhttps://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.pngAdnan Hamid2018-01-31 20:45:372020-02-06 02:39:57Dual Focus Will Help Adoption
Solutions are what users need and the existence of a standard gives them the assurance that models they create will be portable between tools. Put another way, the standard creates a level playing field on which vendors can create tools that provide solutions. When the standard is lacking, deficiencies can be made up for in the tools. One example is path constraints that can be used to constrain the sequence of actions used to create a scenario, rather than combinatorial constraints which constrain numerical values. An example could be that after a burst write, you cannot have another write.
Accellera has just extended the review period for the Portable Stimulus Standard. The committee is now seeking comments up until the end of October. Breker would like to join the committee and say how important it is for users to get involved with this standard. While we, as vendors, have some experience in this area, we are not doing this day in and day out. We need your guidance and feedback.
https://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.png00Adnan Hamidhttps://brekersystems.com/wp-content/uploads/2018/02/breker-logo4.pngAdnan Hamid2017-10-02 00:00:042020-02-06 01:36:06Time To Be Heard
When people talk about the Portable Stimulus Standard (“PSS”) they throw around the term “graph based” as if that somehow clarifies everything. They usually don’t bother to describe what it means, beyond it being some simple mathematical model. Some vendors even confuse it with the term “graphical”. To simplify this confusion, for this blog we will use the term “visual”. This blog will answer questions about how PSS relates to graphs and how those graphs relate to other similar graph-based models already used within the industry.
Inside Portable Stimulus: Filling in the Blanks
/by Leigh BradyA Portable Stimulus tool can do much of the work and allow many tests to be created based on the defined verification objectives.
For those who want all the answers now, Accellera recorded this DVCon training session that goes over the basics of the language and how tools work. I use many of the same examples for continuity purposes, but I will present the material in a different manner.
The Accellera tutorial starts off by defining the syntax of the language. I will concentrate on the abstract notions first and then get into syntax later. You will also read new or unfamiliar terms being thrown around such as declarative, partial specification, inference. I will get to all of that in due course; just don’t worry about the terms to start off with.
Read more
Beyond Portable Stimulus 1.0
/by Adnan HamidWith the release of the 1.0 version of the Portable Stimulus Standard (PSS), the industry now has a solid base on which to build solutions and to ensure that the time and investment made by users to create verification intent models is portable. This should allow them to assess tools and decide which one fits their requirements best and which ones will fulfill their roadmap into the future. Unfortunately, it is not quite as easy as that, because many users have already moved beyond the basics as represented in the standard.
Committee members are taking a well-earned rest after working on this for three years. But we cannot afford to rest too long. The 1.0 release was not the end of the road –– it was merely the on-ramp toward a long road ahead. A lot is missing from the standard.
Read more
The Making of a Standard
/by Adnan HamidThe industry waits with bated breath for the Accellera board to approve the Portable Stimulus 1.0 specification. It has been a long and arduous process over the past four years to get to this point, a process that most people never get to experience. This was my first standard, and to say it was an eye opener is somewhat of an understatement. In this blog, I am not going to dwell on the many bruises I suffered or the technical discussions that often seemed like personal attacks. Instead, I want to make the industry aware of some of the difficulties associated with bringing a new and somewhat revolutionary standard to market.
Breker has been making tools in this space for more than a decade and that presents the first, and very scary, hurdle for a startup company. For most of the period, before the creation of the standards group and throughout its development, we only had one major competitor and they were a much larger company than we were. Would getting the standards process going help us or hinder us?
Read more
System Functionality Includes Software
/by Adnan HamidListening to users is never a bad thing. Users are the people who set Breker along its current direction and during the process of standardizing Portable Stimulus (PS), the ability to talk to an expanded group of users allowed Breker to see a larger portion of the total available market. We learned a lot.
Another group of people are starting to get interested in Portable Stimulus. These are industry consultants who help with methodology insertion and getting the industry up to speed. While not huge in number, these people have something that few others have to offer – a broad view of the market. They have seen more design styles and types of design than would exist within a single company.
Read more
Industry Struggles with System Coverage
/by Adnan HamidDVCon is a great place to talk to design and verification engineers. As the Accellera Portable Stimulus Standard (PSS) gets closer to reality, we were able to share with them during the conference the progress made and the ways in which it may impact their task. Most of them are as excited about PSS as we are. While we have been working in this field for more than a decade and have received a lot of feedback, there are now many more people becoming aware of it and the potential that it has. This provides us with the opportunity to learn as well.
Read more
UVM is Dead! Long live UVM+PS!
/by Adnan HamidWhen the forebears of SystemVerilog and UVM were being created, the world was a different place. Verification was primarily directed testing and code coverage was good enough to signal completion. Development of directed tests was getting to be slow, cumbersome and difficult to maintain. Languages and tools were created that added the ability to randomize stimulus but that created two problems. First, you had no idea what a test had accomplished and second, you had no idea that the design had actually reacted in the right manner. Thus, two additional models became necessary: a combination of checkers and scoreboard and the coverage model. The big problem was, and remains, that the three models are independent models only unified by a thin layer of syntax.
Read more
Dual Focus Will Help Adoption
/by Adnan HamidOne of the great things associated with the development of a standard, such as the Portable Stimulus Standard (PSS), is that it brings together various stakeholders – often a broader selection of people than any single company did business with. When you initially develop a product you gear it toward a particular problem, one that you have some familiarity with. The resulting product attracts engineers who resonate with the product and they provide valuable feedback. This in turn helps to make the product more attractive to engineers with a similar need. If you are not careful, you can have a product that targets a narrow part of the market and that is all you learn to explore. It is the Innovators Dilemma, and can stop a company from developing a general purpose product.
Read more
Solution = Standard + Tool
/by Adnan HamidSolutions are what users need and the existence of a standard gives them the assurance that models they create will be portable between tools. Put another way, the standard creates a level playing field on which vendors can create tools that provide solutions. When the standard is lacking, deficiencies can be made up for in the tools. One example is path constraints that can be used to constrain the sequence of actions used to create a scenario, rather than combinatorial constraints which constrain numerical values. An example could be that after a burst write, you cannot have another write.
Read more
Time To Be Heard
/by Adnan HamidAccellera has just extended the review period for the Portable Stimulus Standard. The committee is now seeking comments up until the end of October. Breker would like to join the committee and say how important it is for users to get involved with this standard. While we, as vendors, have some experience in this area, we are not doing this day in and day out. We need your guidance and feedback.
Read more
Understanding Portable Stimulus Graphs
/by Adnan HamidWhen people talk about the Portable Stimulus Standard (“PSS”) they throw around the term “graph based” as if that somehow clarifies everything. They usually don’t bother to describe what it means, beyond it being some simple mathematical model. Some vendors even confuse it with the term “graphical”. To simplify this confusion, for this blog we will use the term “visual”. This blog will answer questions about how PSS relates to graphs and how those graphs relate to other similar graph-based models already used within the industry.
Read more