Ocean run() Reliability & Netlist Regeneration

Find the canonical resultsDir from the runSimulation script:

cat <netlist_dir>/runSimulation | grep "\-raw"
# → -raw ../../../../../../../../tmp/opt_5t_ota/psf
# Canonical path = /tmp/opt_5t_ota

Fix in virtuoso-cli: sim run no longer auto-sets resultsDir to a temp dir (that was overriding the ADE session path). If resultsDir is nil, sim run now returns a clear error message.

Root Cause 2: sim setup Disrupts Active Session

Calling virtuoso sim setup sends design("lib" "cell" "view") which can reset the Ocean session state. After this, run() returns nil.

Symptom: run() worked → called sim setup → run() now returns nil.

Fix: Don't call sim setup again if a working session exists. Check:

virtuoso skill exec 'asiGetSession(hiGetCurrentWindow())'
# → stdobj@0x... means session is alive

Root Cause 3: OSSHNL-109 — Extraction Timestamp Stale

Symptom: createNetlist returns nil. si.foregnd.log contains:

ERROR (OSSHNL-109): The cellview '…/schematic' has been modified since the last extraction.
Run Check and Save.

artSimEnvLog shows: generate netlist... ...unsuccessful.

Root cause: dbSave(cv) writes the OA file but does NOT update the extraction timestamp. schCheck(cv) is what updates it. Calling dbSave without schCheck leaves the timestamp stale; the next incremental createNetlist sees a mismatch.

Fix: Run schCheck(cv) before dbSave(cv). Or use vcli sim netlist — it auto-recovers by running schCheck + dbSave and retrying when createNetlist returns nil.

# vcli handles OSSHNL-109 automatically (v0.1.7+)
vcli sim netlist --lib FT0001A_SH --cell ota5t

Manual fix in SKILL:

; Get the cv (3-arg form opens "a" mode in IC23; fallback for Ocean-held cv)
cv = dbOpenCellViewByType("lib" "cell" "view")
unless(cv
  cv = car(setof(ocv dbGetOpenCellViews()
                 and(ocv~>libName=="lib" ocv~>cellName=="cell" ocv~>mode=="a"))))
chk = schCheck(cv)
when(car(chk)==0 dbSave(cv))   ; only save if no check errors

Also note: dbReplaceProp(inst "w" ...) sets the display parameter, NOT the netlisted simW. For SMIC PDK n12/p12 width changes, use:

cdfFindParamByName(cdfGetInstCDF(inst) "simW")~>value = "1.3u"

Root Cause 4: Stale or Missing Netlist

After editing a schematic (e.g., adding desVar variables), the netlist becomes stale. createNetlist() requires an ADE L window open for that cell — without it, returns nil.

Root Cause 5: Library Not Registered in Virtuoso Session

Symptom: vcli sim netlist returns an error like:

Library 'FT0001A_SH' is not registered in the current Virtuoso session.
Virtuoso was started from '/home/meow/git/virtuoso-cli'.

Or ddGetObj("FT0001A_SH") returns nil from the bridge.

Root cause: Virtuoso was started from a directory that has no cds.lib including the target library. The DD database is populated at startup from cds.lib files found via CDSHOME, site, and user paths — but NOT automatically from arbitrary directories.

Diagnosis: Check Virtuoso's working directory in CDS.log:

grep "Working Directory" ~/CDS.log
# Expected: meowu:/home/meow/projects/ft0001
# Wrong:    meowu:/home/meow/git/virtuoso-cli

Fix: Start Virtuoso from the project directory:

cd /home/meow/projects/ft0001 && virtuoso &

Distinguish from OSSHNL-109 (both produce err_count == -1 in vcli):

; Returns "found" if library is registered, nil if not
when(car(setof(l ddGetLibList() l~>name=="FT0001A_SH")) "found")

vcli v0.1.7+ runs this probe automatically and returns an actionable error message.

Solution A: vcli sim netlist (handles OSSHNL-109 automatically, v0.1.7+)

# Regenerate netlist — auto-recovers from OSSHNL-109 via schCheck+dbSave retry
vcli sim netlist --lib <lib> --cell <cell>
vcli sim netlist --lib <lib> --cell <cell> --recreate   # force full recreation

Solution B: Restore resultsDir (for Root Cause 1)

virtuoso skill exec 'resultsDir("/tmp/opt_5t_ota")'
virtuoso sim run --analysis dc --timeout 60

Solution B: Direct Spectre Invocation (most reliable, bypasses Ocean)

⚠️ Run from the schematic/ directory, NOT from netlist/ — relative paths inside the netlist resolve from schematic/. Running from netlist/ causes CMI-2011 (cannot open input file).

SCHEMATIC_DIR="/path/to/simulation/cell/spectre/schematic"
PSF_DIR="/tmp/my_results/psf"
mkdir -p "$PSF_DIR"

cd "$SCHEMATIC_DIR" && spectre netlist/input.scs \
  +escchars \
  +log "$PSF_DIR/spectre.out" \
  -format psfxl -raw "$PSF_DIR" \
  +mt -maxw 5 -maxn 5

Then read results:

virtuoso skill exec 'openResults("/tmp/my_results/psf")'
virtuoso sim measure --analysis dcOp \
  --expr 'getData("I0.NM0:gm" ?result "dcOpInfo")'

Advantages: ~200–300ms, no ADE session dependency, works even when Ocean is broken.

Solution C: Add Analyses to Netlist Directly

The ADE-generated input.scs may only have DC. Add AC without opening ADE:

sed -i 's/^dcOpInfo info what=oppoint where=rawfile$/dcOpInfo info what=oppoint where=rawfile\nacSweep ac start=1 stop=10G dec=20 annotate=status/' input.scs

Solution D: Regenerate via ADE GUI (for missing netlist)

1. Open testbench in Virtuoso → Launch ADE L
2. Simulation → Netlist and Run (or Netlist → Create)
3. Confirm input.scs is updated, then virtuoso sim run works again

PSF Signal Naming

Instances inside a subcircuit instantiated as I0 in the testbench:

Find actual signal names:

strings /tmp/results/psf/acSweep.ac | grep "^I0\."

Or in SKILL: openResults("/psf/path") selectResult('acSweep) VF("net1") — if it returns srrWave:0x..., the signal name is correct.

Diagnostic Checklist

1. grep "Working Directory" ~/CDS.log → is Virtuoso's CWD the project directory?
2. ddGetLibList() from bridge → does it include the target library?
3. cat runSimulation | grep -raw → what is the canonical resultsDir?
4. resultsDir() → does it match the canonical path?
5. run() → returns path (OK) or nil (broken)?
6. PSF dir has .dc/.ac files → simulation produced data
7. PSF dir only has simRunData, artistLogFile, variables_file → simulation failed
8. cat <netlist_dir>/si.foregnd.log → contains OSSHNL-109? → use vcli sim netlist to auto-fix

Key Files

<project>/simulation/<cell>/spectre/schematic/netlist/
├── input.scs       # Top-level: parameters, model includes, analyses
├── netlist          # Subcircuit from schematic
├── runSimulation    # Actual spectre command ADE uses (shows original PSF path)
└── netlistFooter    # Testbench instances and stimuli

Notes

• design("lib" "cell" "view") returns nil when no ADE window is open for that cell
• sim setup should only be called once per ADE session
• system("find / ...") hangs the SKILL daemon — blocked by virtuoso-cli bridge
• After bridge hang, restart: Ctrl+C in CIW, reload bridge.il + RBStart

See also: SKILL bridge scoping rules in ~/.claude/projects/.../memory/feedback_skill_bridge_scoping.md