10 Myths About Verification

Every verification engineer should remember this list by heart so that they can educate their managers. The list is so true that I print a copy and pin it to my cube

“This is legacy code no need to verify it”
– Hold your horses! are you 100% sure that you’re dealing with silicon proven code? are you sure that nobody’s touched it since it last worked?

“I can come up with a patch in 5 minutes” – That’s OK as long as you make sure you don’t end up with a verification environment that looks like a bunch of patches hooked together. Ask yourself how easily it would be to modify or fix your environment a week from today? Isn’t it worth it to take a couple of more minutes and write a robust code?

“Start checking and plan as you go”
– A big no no! Don’t be tempted into this. Even if your task looks like a piece of cake, always plan in advance. You’ll be amazed to see how many problems can be completely avoided… With that being said – I know that some engineers out there prefer to get started and only then stop and plan ahead.

“This is really simple, no need for a test plan” – Consider your test plan document as your working contract. Whatever you put in it defines the requirements for your current work. If it’s a simple task then just write a test plan on half a page.

“Verification is not the product, no need to keep software standards” – True, verification is not the product but still – when you’re dealing with thousands lines of code, you’d better make sure there is a certain level of consistency, let alone programming errors.

“Don’t have time to add comments”
– Remember the last time you spent half a day on reverse engineering somebody else’s code? How about your own code?

“Oh I know! Let’s just force the signal from outside”
– Forced wires have this tendency to get forgotten along the way and then reappear at a later stage, usually a week before tapeout… So be extra careful.

“Must have regression running in the background all the time” – Regression runs alone can’t do the job. You must have a “Regression Sitter” to monitor and analyze the results or else – you’re just wearing out your servers.

“We have reached 100% coverage there’s no point in running more tests” – Not really. Your coverage model can only capture what you thought about in advance . Obviously a random test bench is capable of generating additional scenarios that might reveal a bug, so don’t stop at 100%. Instead – enhance the functional coverage model.

“Verifiers should be looking for bugs” – This is a common misconception of what verification is all about. Verifiers should be focused on building a well constructed, robust and complete test bench. Bugs will come out on their own.

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