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TCM versus TCM race conditoin

lalit123

Hi,

This is regarding a race condition (happens at different seed) in one of my sim between 2 different TCMs.

 The scenario is something like this:

The test is implented as a subsequence which contains a do action in its body() @driver.clock {..., the driver.clock is connected to bfm clock as follows:

event a_clock is rise ('clk_from_vhd_tb') @sim;

on a_clock {emit driver.clock};

where driver is the one associated with original sequence.

 In bfm there is a TCM called execute_items()... which is started in its run() is also{... block.

The issue:

In few seeds it is seen that when execute_items() is started there is a garbage struct which is generated.

The bfm interaction mode is PULL_MODE. As per my understanding of get_next_item(), the call is blocked unless a "do" action is seen this avoiding any garbage struct generation.

Thanks in advance for any help.

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  • StephenH

    In your BFM, do you wait for the reset to finish before starting into execute_items()?

    I don't see where get_next_item() could be getting any struct from, unless you do have some sequence that's running.

    Did you use the trace command to see what sequences run, just to sure that only your empty MAIN is run?

    Are you sure that pre_body() and post_body() are not sending anything to the BFM?

    execute_items() won't itself generate a struct unless you explicitly "gen" one yourself.

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  • StephenH

    In your BFM, do you wait for the reset to finish before starting into execute_items()?

    I don't see where get_next_item() could be getting any struct from, unless you do have some sequence that's running.

    Did you use the trace command to see what sequences run, just to sure that only your empty MAIN is run?

    Are you sure that pre_body() and post_body() are not sending anything to the BFM?

    execute_items() won't itself generate a struct unless you explicitly "gen" one yourself.

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