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Contradiction only without collect gen

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Helle there,

I'm currently having a hard time figuring out some odd behaviour.

when I run a test in a certain configuration, specman throws a contradiction and request a rerun with collect gen. When running with collect gen on, the whole test runs flawlessly as it should.

I'm fresh out of ideas after battling the for some time now. The irritating thing is:

when I constrain a struct in two bool flags as true, a method randomly picks one and resets it. 

If I manually reset all of them in the function, everything works as well.
Having both on true also works out fine.

resetting one of them in the method with the code below breaks a list somewhere in a completely different struct of the environment with a contradiction I cannot see. So using the "random resetter" I coded below, Specman goes nuts.

while list_of_desired_errors.count(it == TRUE) > 1
{
    message(FULL,"list_of_desired_errors.size() is still > 1, randomly resetting desired errors");
    var tmp_err_index_list : list of uint;
    tmp_err_index_list.clear();
    for each (err) using index (i) in list_of_desired_errors
    { 
        if err == TRUE
        { 
            tmp_err_index_list.add(i); 
        }; 
    };
    message(FULL,"tmp_err_index_list is: ",tmp_err_index_list);
    var t_uint : uint;
    message(FULL,"t_uint before random assignment is ",t_uint);
    gen t_uint keeping { it in tmp_err_index_list; };
    message(FULL,"t_uint after random assignment is ",t_uint);
    list_of_desired_errors[t_uint] = FALSE;
    message(FULL, "SINGLE_FRAME_ERR resetting error index ",t_uint); };
};

Ideas, anyone?

regards


Originally posted in cdnusers.org by SomeDude
Parents

  • thx for your reply!

    I'll try to clarify a bit more. The frame is driven over different interfaces and has various formats. Depending on those interfaces and formats, some errors are valid and some are not. As the testwriters want it very easy, they constrain for example three errors to true and all the others to false. Additionally they set the error_mode to single_error (as opposed to no_error and multi_error). So the model has to check if the picked errors are even possible, if not it resets them. The remaining errors are randomly reset resulting in only one set error flag. So much for directed testing.

    In random unconstrained mode all flags are completely randomly generated. Then again, the impossible ones will be reset and the remaining possible flags considered. In multi-error-mode at least 2 random/valid flags will be set, in single-err-mode at least one will be set and if more than one are set, they will randomly be reset.

    The reason to jump through all these hoops is the goal to get the most possible random distribution of errors depending on interface and frame_type.

    The generator based approach works fine if the test writer knows what the interface and/or frame_type can do. Unfortunatley I cannot rely on that. You how how it works: As soon as the eVC throws a constraint-contradiction it's not the user's but the eVC's fault. :/

    I'm still waiting for Spm 6.20.003 to be installed, it's moving up in the admin's pipeline. IF the problem still shows in the newer version, I will file a bug report. Till then, the ugly (Option 2), but working version has not failed me once over hundreds of frames. I presume it's a false memory handling that influences something it shouldn't influence. But that's pure speculation, unfortunately Specman is not Open-Source or we could debug all the way. The fact that is works flawlessly in Collect-Gen Mode is indicator enough that it might be a tool problem.

    by the way, the code tags here suck whole lemons. If one could edit own posts, one could post by try and error, but it really discourages posting code snippets.

    Will keep you updated


    Originally posted in cdnusers.org by SomeDude
Reply

  • thx for your reply!

    I'll try to clarify a bit more. The frame is driven over different interfaces and has various formats. Depending on those interfaces and formats, some errors are valid and some are not. As the testwriters want it very easy, they constrain for example three errors to true and all the others to false. Additionally they set the error_mode to single_error (as opposed to no_error and multi_error). So the model has to check if the picked errors are even possible, if not it resets them. The remaining errors are randomly reset resulting in only one set error flag. So much for directed testing.

    In random unconstrained mode all flags are completely randomly generated. Then again, the impossible ones will be reset and the remaining possible flags considered. In multi-error-mode at least 2 random/valid flags will be set, in single-err-mode at least one will be set and if more than one are set, they will randomly be reset.

    The reason to jump through all these hoops is the goal to get the most possible random distribution of errors depending on interface and frame_type.

    The generator based approach works fine if the test writer knows what the interface and/or frame_type can do. Unfortunatley I cannot rely on that. You how how it works: As soon as the eVC throws a constraint-contradiction it's not the user's but the eVC's fault. :/

    I'm still waiting for Spm 6.20.003 to be installed, it's moving up in the admin's pipeline. IF the problem still shows in the newer version, I will file a bug report. Till then, the ugly (Option 2), but working version has not failed me once over hundreds of frames. I presume it's a false memory handling that influences something it shouldn't influence. But that's pure speculation, unfortunately Specman is not Open-Source or we could debug all the way. The fact that is works flawlessly in Collect-Gen Mode is indicator enough that it might be a tool problem.

    by the way, the code tags here suck whole lemons. If one could edit own posts, one could post by try and error, but it really discourages posting code snippets.

    Will keep you updated


    Originally posted in cdnusers.org by SomeDude
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