Sequence interview bank.
[INT][SENIOR][UVM-CODE]
Q: start_item vs start_item(req)?
A:
start_item(req, -1, parent) for child seq; default for inline item.
FOLLOW-UP TRAP: Wrong parent — sequencer resolution fails.[INT][SENIOR][UVM-CODE]
Q: Objection in sequence vs test?
A:
raise in test main or seq pre_start; drop in seq post_body or test — match pairs.
FOLLOW-UP TRAP: Objection leak hang.[INT][SENIOR][UVM-CODE]
Q: Virtual sequence layering?
A:
vseq starts child seq on sub-sequencers via `uvm_do_on macros or start on p_sequencer.
FOLLOW-UP TRAP: Starting on wrong sequencer.[INT][SENIOR][UVM-CODE]
Q: grab vs lock?
A:
grab: exclusive access with ungrab. lock: simpler exclusive — know team style.
FOLLOW-UP TRAP: Deadlock two virtual seqs grabbing.[INT][SENIOR][UVM-CODE]
Q: Sequence library arbitration?
A:
uvm_sequence_library rand pick weighted sequences.
FOLLOW-UP TRAP: No weights — uniform unwanted.[INT][SENIOR][UVM-CODE]
Q: pre_body post_body use?
A:
Hooks for objection, delay, logging — keep body focused on items.
FOLLOW-UP TRAP: Heavy logic only in body.[INT][SENIOR][UVM-CODE]
Q: Rand stability in seq?
A:
set_rand_seed from test plusarg; same seed replay.
FOLLOW-UP TRAP: Different seeds each run — debug hard.[INT][SENIOR][UVM-CODE]
Q: Constraint on seq item?
A:
Inside item class — seq randomizes before start_item.
FOLLOW-UP TRAP: Constraining in seq body on non-rand fields.[INT][SENIOR][UVM-CODE]
Q: Response handler in seq?
A:
get_response(rsp) after start_item with rsp enabled.
FOLLOW-UP TRAP: Blocking rsp on pipelined driver.[INT][SENIOR][UVM-CODE]
Q: Default sequence type?
A:
uvm_config_db set default_sequence on sequencer.
FOLLOW-UP TRAP: Hardcoded seq in driver.[INT][SENIOR][UVM-CODE]
Q: Sequence on null sequencer?
A:
p_sequencer cast fails — check factory create path.
FOLLOW-UP TRAP: m_sequencer not set.[INT][SENIOR][UVM-CODE]
Q: Layered seq objection count?
A:
One objection per top virtual seq or per child — pick policy.
FOLLOW-UP TRAP: Double raise from child and parent.[INT][SENIOR][UVM-CODE]
Q: Sequence item clone?
A:
Clone before randomize for unique items per iteration.
FOLLOW-UP TRAP: Reuse same item object.[INT][SENIOR][UVM-CODE]
Q: Kill sequence mid-flight?
A:
seq.kill() — driver must handle item_done or hang.
FOLLOW-UP TRAP: Kill without driver cleanup.[INT][SENIOR][UVM-CODE]
Q: uvm_do macro pitfalls?
A:
Hidden create/randomize — prefer explicit in interviews for clarity.
FOLLOW-UP TRAP: Can't explain what uvm_do does.[INT][SENIOR][UVM-CODE]
Q: Sequence timeout?
A:
wait fork or timeout in parallel with body.
FOLLOW-UP TRAP: Infinite body on stuck bus.[INT][SENIOR][UVM-CODE]
Q: Seq item field automation?
A:
`uvm_field_* for print/compare — interview may ask compare in scoreboard.
FOLLOW-UP TRAP: Manual compare all fields.[INT][SENIOR][UVM-CODE]
Q: Virtual seq env access?
A:
Cast p_sequencer to virtual_sequencer; get sub sequencer handles.
FOLLOW-UP TRAP: Direct agent lookup from seq.[INT][SENIOR][UVM-CODE]
Q: Sequence arbitration UVM_MAX_QUIT?
A:
Separate from seq — test level quit count.
FOLLOW-UP TRAP: Confusing seq errors with test quit.[INT][SENIOR][UVM-CODE]
Q: Whiteboard basic seq 8 min?
A:
item class + seq body start_item/finish_item + objection mention.
FOLLOW-UP TRAP: Full env before seq body.