Running a multiplexed 4-digit 7-segment clock on ESP32/QEMU froze the
browser for minutes after Run — evaluate probes waited 40-90 s, and before
the first fixes the sim WebSocket eventually died (code 1006) with the page
never recovering. CPU-profiled on staging; four compounding per-GPIO-edge
costs, in profile order:
updateComponentState minted a new components array per edge
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The store setter rebuilt `components` (and one properties object) on EVERY
edge even when the state didn't change. The breadboard is direct-wired to
13 board pins, so segment toggles produced thousands of store sets per
second; every subscriber re-rendered each time, and the canvas subscription
effect (deps: [components, ...]) re-subscribed all pin listeners in a loop.
Now a no-op guard returns prevState unchanged, and breadboards are treated
as self-managed (they have no visual on/off state to echo).
CompilationConsole re-rendered every log line per editor render
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The post-compile console holds hundreds of lines; each render called
Date.toLocaleTimeString per line (~0.2 ms each — it builds a fresh Intl
formatter every call). Profile: 162 s of self time in LogLine over a 337 s
window, in ~150 ms tasks. LogLine is now memoized (entries are immutable),
timestamps go through one shared Intl.DateTimeFormat, and the console
itself is React.memo'd against parent re-renders.
Per-edge full SPICE re-solves
------------------------------
PinManager requested a FULL netlist rebuild+solve on every 'mcu' edge.
Now only the edge that newly classifies a pin as MCU-output triggers the
rebuild (that's what emits the pin's V-source); steady-state updates flow
through connectMcuEdgesToService's per-pin coalesced alterSource path.
The start.ts resolve hook is trailing-throttled (33 ms) for the other
per-edge callers (RP2040, custom chips), the service's pending-edge queue
drains on a 33 ms gap timer instead of replaying back-to-back, and new
edges arriving inside the gap queue instead of soloing a solve.
STM32 / Pi reverse pin-name mappings added to connectMcuEdgesToService so
those boards keep fine-grained updates now that the full-tick storm is
gone (PA0/PC13-style and GPIO-style names never matched before).
wokwi-7segment re-rendered per segment write
---------------------------------------------
element.values now flushes at most every 8 ms per display (trailing write
guaranteed), instead of re-rendering the 32-shape SVG per edge.
Also: CLN (colon) pin support for 7-segment clock faces — wired CLN now
drives colon/colonValue in both the attachEvents path and the QEMU
onPinStateChange path; it was silently ignored, so clock colons never lit.
Verified on staging with the failing project: main-thread probes drop from
40-90 s waits (324 long tasks, 52.6 s blocked in 150 s) to 5-11 ms
(2 long tasks, 179 ms), display shows 12:00 with the colon blinking at
1 Hz from the first seconds after Run.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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