Architecture & Closure Interview Hub: Block to Sign-Off

Architecture interviews test judgment, not trivia

Senior architecture questions ask you to design under constraints — reuse a block VIP at chip, structure env/test for regression scale, merge coverage across seeds, sign off with evidence, triage nightly reds, and answer 'are we done?' with a plan-backed package.

Sub-lessons in this topic

1. block-to-soc-qa — passive flip, virtual sequences, integration scoreboard.

2. env-test-structure-qa — test base, config distribution, virtual sequencer wiring.

3. coverage-merge-closure-qa — UCDB merge, hole triage, directed closure.

4. regression-signoff-qa — metrics dashboard, waivers, trend lines.

5. night-triage-qa — bucket classification, seed repro, owner assignment.

6. verification-done-qa — plan compliance, P0 holes, risk communication.

[INT][SENIOR][UVM] architecture answer chain

1. MECHANISM   — what changes at each hierarchy level
2. MOTIVATION  — reuse economics and sign-off evidence
3. WHEN-TO-USE — block vs subsystem vs chip patterns
4. PITFALL     — double-drive, orphan coverage, premature sign-off
5. EXAMPLE     — one concrete SoC integration story

[INT][SENIOR][UVM] reuse ladder (whiteboard every time)

  BLOCK:      active agents, block SB, block coverage plan
  SUBSYSTEM:  mix active/passive, integration SB, scenario vseqs
  CHIP/SoC:   mostly passive monitors, chip SB, SW-like vseqs
              merge block + chip UCDB before closure review

Key takeaways

• Clarify scope: block, subsystem, or chip — before answering architecture.

• Reuse ladder + check pipeline are the two whiteboard drills for this hub.

• Closure answers cite merged func cov and P0 holes — not feelings.

Common pitfalls

• Rebuilding agents per level instead of config-driven reuse.

• Quoting code coverage % as sole sign-off metric.

• Night triage by rerunning the farm without seed repro.

Interview delivery for architecture scenarios

Offer a trade-off unprompted — e.g. passive reuse vs re-stimulus cost — then sketch the env tree and monitor→check pipeline on the whiteboard while narrating.

// architecture principle interviewers expect you to cite
class bus_agent extends uvm_agent;
  bus_cfg cfg;
  bus_monitor mon;
  bus_driver drv;
  bus_sequencer sqr;

  function void build_phase(uvm_phase phase);
    super.build_phase(phase);
    mon = bus_monitor::type_id::create("mon", this);
    if (cfg.is_active == UVM_ACTIVE) begin
      sqr = bus_sequencer::type_id::create("sqr", this);
      drv = bus_driver::type_id::create("drv", this);
    end
  endfunction
endclass

• Pause: 'Do you want block-level detail or chip integration overview?'

• Name published VIP API: cfg + seq library + analysis port.

• Sign-off story: merged bins, open P0 list, waiver audit, trend.