Home > Community > Forums > Functional Verification > FSM_NoDeadlock - Explored (IFV)

Email

* Required Fields

Recipients email * (separate multiple addresses with commas)

Your name *

Your email *

Message *

Contact Us

* Required Fields
First Name *

Last Name *

Email *

Company / Institution *

Comments: *

 FSM_NoDeadlock - Explored (IFV) 

Last post Mon, Jul 15 2013 6:03 AM by JoergM. 3 replies.
Started by Buvna 14 Jul 2013 09:06 PM. Topic has 3 replies and 503 views
Page 1 of 1 (4 items)
Sort Posts:
  • Sun, Jul 14 2013 9:06 PM

    • Buvna
    • Top 500 Contributor
    • Joined on Fri, May 31 2013
    • Posts 19
    • Points 245
    FSM_NoDeadlock - Explored (IFV) Reply

    Hello,

    I've been using the IFV tool for quite sometime now and I notice that when I run FSM assertions under AFA, No deadlock assertions remain explored while the others pass easily. Is there anyway to improve this?

    Thanks 

    Filed under:
    • Post Points: 20
  • Sun, Jul 14 2013 11:44 PM

    • JoergM
    • Top 500 Contributor
    • Joined on Thu, Jul 17 2008
    • Munich, Bavaria
    • Posts 28
    • Points 550
    Re: FSM_NoDeadlock - Explored (IFV) Reply

    Hi,

    besides increasing the effort and partitioning the design there is not much you can do. Note that the FSM NoDeadlock check is a very complicated check that has to verify the FSM in context of all other state bits as well as excluding unfairness on all inputs.

    There is a change in FSM NoDeadlock checks starting in 13.1 that will improve performance significantly, at the cost of failures due to unfair input behavior. I recommend to try that and share the experience.

    Jörg.

    Filed under:
    • Post Points: 20
  • Mon, Jul 15 2013 1:29 AM

    • Buvna
    • Top 500 Contributor
    • Joined on Fri, May 31 2013
    • Posts 19
    • Points 245
    Re: FSM_NoDeadlock - Explored (IFV) Reply

    Hello,

    Thanks for the immediate response.

    I tried the same RTL with the 13th version. All these deadcode checks failed as Fail (Inf). What do you mean by unfair input behavior?

    Thanks 

    Filed under:
    • Post Points: 20
  • Mon, Jul 15 2013 6:03 AM

    • JoergM
    • Top 500 Contributor
    • Joined on Thu, Jul 17 2008
    • Munich, Bavaria
    • Posts 28
    • Points 550
    Re: FSM_NoDeadlock - Explored (IFV) Reply

    Hi,

    from the IFV "Whats New":

    Updates to deadlock state

    In this release, the deadlock state property has been enhanced to check that the FSM cannot take any transition to the same state under any possible input combination.

    This deadlock state is supported by all engines and results in an improved performance.

    For complete information, see the section titled, "FSM Checks" in Chapter 10 of the Formal Verifier User Guide.

    What is implicitly explained here is the fact, that any input, that can control the outgoing transition of a FSM state, is now allowed to stall the FSM in 13.1, resulting in a noDeadlock failure. It is now required from the user to analyze and decide if that scenario is possible in the intended system context or not. If not, the user may add a fairness constraint like "eventually! !stable(<input>) and reduce unfairness manually.

    Joerg.

    Filed under:
    • Post Points: 5
Page 1 of 1 (4 items)
Sort Posts:
Started by Buvna at 14 Jul 2013 09:06 PM. Topic has 3 replies.