`uvm_info("SCB", "matched id=0x42", UVM_HIGH) // verbosity-gated
`uvm_warning("CFG", "default timeout used") // always prints, no count
`uvm_error("SCB_MISMATCH", "addr 0x1000 exp=FF act=00") // always prints, counts
`uvm_fatal("NOVIF_APB", "vif not set in config_db") // prints, counts, stops simLegend: [UVM]
SEVERITY DECISION TREE — which macro to use?
Is the condition a test failure?
│
├─ NO ── Is it informational debug output?
│ ├─ YES → `uvm_info("ID", msg, UVM_HIGH)
│ └─ NO → `uvm_warning("ID", msg)
│
└─ YES ── Can simulation continue meaningfully?
├─ YES → `uvm_error("ID", msg) ← counts toward FAIL
└─ NO → `uvm_fatal("ID", msg) ← counts + stops sim
Rule of thumb:
• uvm_info — debug visibility, no impact on PASS/FAIL
• uvm_warning — unexpected but non-fatal (missing config default)
• uvm_error — check failure, sim continues, test will FAIL
• uvm_fatal — unrecoverable (no vif, null pointer), sim stopsAction Flag Effect
──────────────────────────────────────────────────────
UVM_DISPLAY Print message to stdout (sim log)
UVM_LOG Write message to report log file
UVM_COUNT Increment severity counter on report server
UVM_EXIT Stop simulation immediately (fatal default)
UVM_STOP Stop simulation after current delta cycle
Default actions by severity:
uvm_info → DISPLAY | LOG
uvm_warning → DISPLAY | LOG | COUNT (warning count tracked)
uvm_error → DISPLAY | LOG | COUNT
uvm_fatal → DISPLAY | LOG | COUNT | EXITSeverity Verbosity-gated? Counts? Stops sim? Use for
──────────────────────────────────────────────────────────────────────
UVM_INFO YES NO NO debug visibility
UVM_WARNING NO YES* NO unexpected non-fatal
UVM_ERROR NO YES NO check failures
UVM_FATAL NO YES YES unrecoverable errors
* warning count tracked but typically not used for PASS/FAIL// Override action for a component — suppress display, keep count
set_report_severity_action(UVM_ERROR, UVM_LOG | UVM_COUNT);
// Max quit count — stop after N errors (avoid log explosion)
set_report_max_quit_count(50);
// Or via plusarg: simv +UVM_MAX_QUIT_COUNT=100Only uvm_info is verbosity-gated; errors and fatals always print and count.
Use uvm_error for check failures; uvm_fatal only when sim cannot continue.
set_report_max_quit_count prevents runaway error loops in broken tests.
uvm_info for check failures — test passes even when condition is wrong.
uvm_fatal for recoverable mismatches — stops sim before check_phase drain.
uvm_warning for real bugs — warnings do not fail the test.