Codex v26.318.11754 pegs CPU to 70%+ immediately on launch (macOS ARM64)

Codex v26.318.11754 pegs CPU to 70%+ immediately on launch (macOS ARM64)

Environment:

• Codex version: 26.318.11754 (Electron 40.0.0)
• macOS: 26.3.1 (25D2128) — Apple Silicon (ARM64)
• RAM: 48GB (30GB in use at time of observation)

Description:
Codex consumes 50-70% CPU immediately upon launch and never settles to an idle state. The issue is 100% reproducible —
quitting and relaunching triggers it every time. No projects are open; this happens on bare startup.

Observed behavior:

• PID shows state R (actively running, not sleeping) continuously
• Physical memory footprint: ~271MB (peak ~275MB)
• CPU usage does not decrease over time — sustained at 50-70% indefinitely

Stack trace analysis (via /usr/bin/sample):
All 2,316 samples across a 3-second capture land in the V8 engine on the main thread:

ScriptCompiler::StartConsumingCodeCacheOnBackground
→ V8 Isolate::RequestInterrupt
→ node::PrincipalRealm::http2session_on_origin_function

Multiple background threads (ThreadPoolForegroundWorker, ThreadPoolServiceThread, PerfettoTrace) are also stuck in V8
allocation paths, with repeated frames through rust_png::Reader::try_get_gama (Chromium PNG gamma decoding),
suggesting an image asset decode loop or recompilation cycle during startup.

Impact:

• System load average climbs from ~2 to ~18 with Codex open
• CPU idle drops to <1%
• Triggers thermal throttling (kernel_task CPU spike) on sustained runs

Diagnostic files:
Full sample output attached: Codex_2026-03-21_113731_Xluv.sample.txt

Workaround:
None found. Clearing ~/Library/Application Support/Codex/{Cache,Code Cache,GPUCache} has not been tested yet.