Verification in the trenches: an end user’s viewpoint on VMM1.2
Posted by Shankar Hemmady on November 11th, 2009
Dr. Ambar Sarkar, Chief Verification Technologist, Paradigm Works Inc.
As a soup-to-nuts functional verification consultant, I always find myself as an integral member of my client’s verification team, be it during the project planning stage or during the mad rush end of the tape-out. The roles include everything; being an individual test writer, a verification architect, or even as the verification lead for a globally dispersed large verification team. And yes, the schedules are invariably aggressive, and the budgets tight.
So how does having a sound verification methodology such as VMM help? Broadly speaking, it offers a framework within which the verification engineer can get the job done efficiently. Instead of spending time on environment and methodology issues such as wondering about how to configure all the verification components to the same setting, he or she can focus more on identifying the application specific scenarios and easily configuring the environment to generate those. The challenge, of course, is being able to understand exactly how the methodology helps within the context of a given project.
Given this challenge, I often find myself explaining to teams, in terms of their existing verification environments, how a methodology or a feature can help and the corresponding trade-offs involved. Of course, not every feature is applicable to the needs of a given team, so I pay extra attention in explaining how a feature helps, its pros-and-cons, and how to best integrate it with the current verification environment.
In this series of blog posts, I will share my opinions on how the features newly introduced with the VMM1.2 release can help or could have helped the projects I have been directly involved with so far. Of course, I will not share the gory details, but I hope to share enough so that anyone looking at these new features can evaluate them from an end-user’s perspective.
So what’s new with VMM1.2? And how does it help? Check out the table below where it identifies some of the key features, and a “one-line” description for each. This table reflects how I see these features potentially benefit the projects I have worked with; your mileage may vary.
|
Feature |
Description |
|
vmm_object
|
A base class for all object types, making it easy to traverse hierarchies and locate objects by name |
|
vmm_unit
|
A base class for all structural elements such as generators, transactors etc, making it easier to synchronize their actions when executing the phases of a test |
|
vmm_timeline
|
Allows users to coordinate and even define custom phases |
|
vmm_test
|
Adds support for multi-test management |
|
`vmm_unit_config_xxx
|
Macros to configure and build verification environment structure in a top-down manner |
|
vmm_opts
|
Flexible options handling, command-line or otherwise |
|
vmm_rtl_config
|
Facilitates covering cases where a number of structural configurations for the RTL exist |
|
vmm_tlm
|
Making sure your components can really connect to each other and foreign objects in a “plug and play” manner |
|
regular expressions
|
A very convenient way to access objects by name and set specific properties to them |
|
`vmm_class_factory
|
Macros to replace and extend object functionality anywhere in the code hierarchy conveniently, and support top-down build process |
Table 1. VMM 1.2 Features
While the “one-liner”s above help get an overall idea about the feature, the Verification in the trenches series of blog posts will describe each in further detail starting with their motivation, pros and cons, and how to incorporate them quickly. The hope is that you will be able to judge for yourself how some of the features described can help your current and future project needs.
Feel free to comment/share your opinions and experiences. I will be very interested in hearing from folks in the trenches. How are these features working out for you? Are you getting the benefits as you had hoped? Which one of these features you can use today? Drop me a line! Share!
