v3.3.97 (UV_THREADPOOL_SIZE 64→8) was a decisive win — mean event-loop-delay at
70 active uploads dropped 200ms→~11ms (18×), rss 577→287MB, renderer healthy in
14/15 windows. But the user reports it is still not perfectly smooth. A focused
multi-agent investigation plus an adversarial review localized the residual to
TWO distinct, separately-measured spike sources:
1. Read-bursts. In the tail windows the file-read histogram inverts: FSReqCallback
climbs to 66-70 against threadpool=8 (~8.75× queue depth) while SimpleWriteWrap
(socket writes) collapses to 4-24 and mean delay rises to 30-42ms. GC is ruled
out (gcMax ≤27ms in every window). The clean inversion at a stable active=70 /
pending=1287 shows the reads are causal, not a symptom of a block elsewhere.
2. A suspected synchronous config-persist stall. save() → load() reparses the whole
electron-config.json — which now carries the 1287-job pending queue nested in
globalSettings plus full history — on every persist (because _atomicWrite nulls
the read cache), then _serializeForDisk JSON.stringify(…, null, 2) of all of it.
One tail sample (max 1021ms, heap spiking to 142MB) fits a large synchronous
structuredClone+stringify, but it is a single confounded point, so this build
only INSTRUMENTS the path rather than asserting the cause.
This release ships one behavioral change (kept to a single variable so the next
log attributes cleanly) plus measurement:
- highWaterMark 256KB→1MB in all five streaming read loops (lib/hosters.js,
doodstream/voe/vidmoly CHUNK_SIZE consts, and the inline value in
clouddrop-upload.js:108 — NOT the 16MB server chunk at clouddrop-upload.js:12).
UV_THREADPOOL_SIZE stays 8. This deepens each stream's read-ahead cushion from
~0.43s to ~1.7s at the per-stream rate, so a stream tolerates the threadpool
queue without starving its socket write, and cuts read-completion callbacks and
per-chunk Buffer allocations ~4×. Byte-correctness is unaffected: Content-Length
is preamble+fileSize+epilogue, independent of chunk size, and the chunk size
never touches the multipart boundaries. Fully reversible; a dedicated read-
concurrency semaphore is held in reserve if 1MB does not clear the bursts.
- config-store.js now times load() (the full reparse, which the account-failed
handler also hits per failure) and the _commit serialize, logging
`config-load …` / `config-serialize wall=…ms bytes=… hist=… queue=…` when the
synchronous work exceeds 20ms. load() is split into a timing wrapper + _loadImpl;
the timer is a no-op until main.js wires configStore.setPerfLog → logInfo.
The renderer batch-drain fix for the one observed 243ms longtask is intentionally
deferred: that jank is downstream of the main-thread read-burst flooding IPC, so
fix#1 should make it self-heal; bundling it would confound the measurement and
touch the progress hot path. All 397 tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The v3.3.96 eventloop-delay logs from a real 70-connection run pinpointed the
high-concurrency lag to the file-read path. At a CONSTANT active-job count the
process flips between two clean regimes:
HEALTHY ELD ~11ms, rss 268-308MB: SimpleWriteWrap ≈ active, FSReqCallback ≈ 0-1
BLOCKED ELD 49-217ms, rss 540-610MB: FSReqCallback ≈ active (62-71 reads in
flight), SimpleWriteWrap ≈ 0-4
Both the ELD spike and the rss balloon track FSReqCallback (libuv-threadpool file
reads) exactly — not crypto, not the renderer, not GC alone. All five uploaders
read identically via fs.createReadStream({highWaterMark: 256KB}); byse/doodstream/
voe run through the generic uploadFile in hosters.js (no dedicated module).
This build is both a candidate fix and a discriminator, per advisor review:
- UV_THREADPOOL_SIZE 64→8 (main.js:1). One reversible line, NOT an upload cap —
70 uploads still run. 8 concurrent 256KB reads sustain ~100MB/s, far above the
41MB/s aggregate, so it cannot bottleneck throughput even on the slow VM disk.
Strong suspicion that tp=64 made it worse: it removed the natural read-
serialization (default 4 threads) and let all 70 streams' reads fire at once,
flooding the loop with completion callbacks in lock-step bursts.
- ELD line now also logs heap=heapUsed ext=external ab=arrayBuffers and
gc=/gcTotal=/gcMax=ms (PerformanceObserver entryTypes:['gc'], reset per window).
The 70×256KB ≈ 18MB of read buffers cannot account for the ~300MB rss swing —
that is heap/object churn, so GC must be measured directly.
Decision rule for the next real-run log:
- ELD drops with tp=8 → read over-parallelism confirmed (keep 8 or add
a dedicated read-semaphore).
- ELD high + GC pauses align → heap churn, hunt the allocator.
- ELD high + GC flat → causation was reversed, pivot.
No upload-behavior change; the concurrency cap the user explicitly rejected is
untouched.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The v3.3.94 measurement computed the main-process event-loop delay, CPU%, per-hoster connection distribution and transient error counts, but logged only '[INFO ] perf': logInfo(ctx, msg) treats a string first arg as the whole message and discards the second, so the payload was thrown away (confirmed in the user's upload-debug.log). Pass the line as a single argument so the real numbers reach the log.
Also: assets/ was missing from the electron-builder files list, so app_icon.ico was never packaged into the asar — new Tray() threw an unhandled rejection on every startup and left no tray icon. Package the icons and wrap createTray in try/catch with a nativeImage fallback so a missing/invalid icon can never crash tray creation.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
