perf(serve): cache the /api/status profile-gateway topology scan (salvage #71396) - #76969
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kshitijk4poor merged 1 commit intoAug 2, 2026
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/api/status is the desktop's boot liveness probe (polled ~1/s) but since NousResearch#60537 every call ran a full topology scan — per-profile yaml.safe_load (pure-Python loader), psutil process probes, realpath walks — in the default executor. On multi-profile installs concurrent polls pile up and hold the GIL 14-16s, starving the event loop: the WS sidecar cannot flush gateway.ready, the desktop times out into the next stall, and boot escalates to the 'Hermes couldn't start' overlay (NousResearch#60800). Memoize the scan behind a 10s TTL with a collapse lock so concurrent polls share one scan. Topology only changes on gateway start/stop, so a <=10s stale badge is an acceptable trade for not starving the loop. The cache also keys on the collector's identity: tests monkeypatch _collect_profile_gateway_topology per case, and the identity check keeps them hermetic (a swapped collector is a miss) without a reset hook. py-spy captures during a failing boot land in _profile_platform_ports -> yaml.safe_load on executor threads (7 profiles, Windows). After: one cold-start scan, zero recurring stalls, desktop boots.
kshitijk4poor
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August 2, 2026 17:37
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Salvages #71396 by @lost9999 — commit cherry-picked to preserve authorship. Merges clean; no changes to the contribution.
Context — honest premise update
The PR was written against a desktop-boot GIL-starvation symptom: the desktop polled
/api/status~1/s during boot, each uncached_collect_profile_gateway_topologycall walks 7+ profile homes (yaml.safe_load + psutil + realpath) in the executor, and concurrent polls piled up holding the GIL for 14-16s, starvinggateway.ready. Since then, 23cb26c moved desktop boot readiness to/api/health, so the boot symptom itself no longer occurs on current desktops.The cache still carries real value, which is why we're landing it:
/api/statusremains polled by the web sidebar every 10s, the statusbar every 60s, Hermes Cloud Portal, multiple desktop windows, and the legacy boot-fallback for pre-0.19.0 backends. The topology scan is genuinely expensive and identical across concurrent callers — a 10s TTL with a collapse lock deduplicates all of it.What the fix does
10s-TTL double-checked-locking cache around the topology scan, with a function-identity guard that makes monkeypatched collectors an automatic cache miss (test hermeticity without reset hooks).
Verification
Closes #71396 (superseded by this salvage — original author credited via cherry-pick authorship).