UVM_ERROR: did not produce an item within an NBA delay

[dmq0420]

Does anyone meet this UVM_ERROR? The full log infomation is:

UVM_ERROR @ 89000: did not produce an item within an NBA delay. Sequences should not consume time between calls to start_item and finish_item. Returning null item.

UVM_ERROR @ 90000: get_next_item/try_next_item called twice without item_done or get in between

In fact, the test not always failed. But only failed for some seeds and the error message is always like above when failed.

In my sequence, I'm using lots of "fork join_any" and "fork join". In the top sequence, it instantiate several sub-sequences and there are many "fork" in each sequences.

What I want to know is why UVM report such error? And how to debug this error?

[uwes]

the error is because you indicated to send an item, you got granted but failed to deliver the item without a delay. typical issues are:

- a delay between grant and delivery of an item (this can only happen if you utilize the "fine grained" sequence control. for instance between start_item+finish_item)

- your process asking for the grant has been terminated. as a result the terminated process cannot deliver the item anymore. this could be due to a process::kill,suspend; disable fork, the end of a phase (terminating the process),...

/uwe

[dmq0420]

Thanks uwe.

It seems that most probably the issue disable fork. So how to use the "disable fork" or ".kill()" safely after we already start a sequence?

[dmq0420]

Does anyone have ideas about this error?

[uwes]

did you try to stop the sequence using sequence.kill() before you kill the thread with "disable fork" ?

[dmq0420]

No. I used the sequence.kill() after I killed the thread by "diable fork". Here is my code.

fork

begin

...

end

begin

...

end

begin

fork

begin

`uvm_do(seq0);

end

begin

`uvm_do(seq1);

end

join_any

disable fork;

seq0.kill();

seq1.kill();

end

join

disable fork;

[uwes]

hi,

did you use a module or program block for your issue and is this a cadence simulator?