The Mac/iOS client's wall around ~380 Mbps on a 2.5 G path is the receive
drain, not the transport: a loopback speed-test pushes 380/600/1000 Mbps at
0.0% loss, but Darwin has no recvmmsg(2), so the macOS client was doing one
recv() syscall per packet — ~40-90k syscalls/s on one core. When the recv loop
can't drain fast enough the kernel socket buffer backs up and drops, which the
client sees as a sustained stream stalling/freezing in the 300-400 Mbps range
(and an immediate "session ended" when a 500 Mbps+ first keyframe bursts in).
- core/transport: flip recvmsg_x (the batched Darwin recv, ~30x fewer syscalls)
from opt-in to default ON, opt-out via PUNKTFUNK_RECVMSG_X=0. Keeps the
auto-fallback to the scalar loop on any unexpected syscall error. The Apple CI
swift-test loopback now exercises this path by default.
- packaging/kde host.env: enable PUNKTFUNK_GSO=1 — UDP segmentation offload on
the host send path (one sendmsg per ~64 packets), the dominant lever above
~1 Gbps. Already wired (send_sealed -> send_gso) with sendmmsg auto-fallback.
- apple SpeedTestSheet: lengthen the bandwidth probe 2 s -> 5 s so the measured
number stops swinging wildly (50 vs 900 Mbps on the same link) — long enough
for steady-state send + recv drain to settle. Matches host MAX_PROBE_MS.
- host capture: PUNKTFUNK_SYNTH_NOISE synthetic high-entropy source for
reproducible throughput testing of the encode->FEC->send->recv path.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
A 6-agent adversarial audit of the client (11 confirmed of 39 findings, the rest
filtered) drove these:
- fix: SessionAudio ring buffer — guard a write larger than the ring (would push
readIdx past writeIdx and corrupt the buffer; never happens, but guard not corrupt).
- fix: CADisplayLink retain cycle (stage-2 presenter) — a weak-target DisplayLinkProxy
so the view can deallocate (the link retains its target); stage-2 teardown added to
both StreamView/StreamViewController deinits as a safety net.
- fix: GamepadFeedback deinit { flag.stop() } — the drain thread holds the connection
strongly and self weakly, so an abrupt teardown without stop() would leak it.
- refactor: centralize the 12 UserDefaults/@AppStorage key literals (scattered across
8 files) into one DefaultsKey enum — a typo silently splits a setting's reader from
its writer.
- docs: RumbleRenderer @unchecked Sendable invariant; the HID digit-row table; the
stage-2 layer compositing.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The Apple speed test asked for only 400 Mbps, capping the measured throughput
there and hiding the link's real headroom. Request the host's full
MAX_PROBE_KBPS (3 Gbps) instead, and raise the recommended-bitrate clamp from
500 Mbps to the host's 2 Gbps session ceiling so a fast measurement yields a
usable recommendation.
Also fix the stale caps left when the host clamps were raised (0cd02e7): the
resolved-bitrate range and the probe doc comments (abi.rs, client.rs,
regenerated header), plus the section 9 roadmap copy, now read 3 Gbps probe /
2 Gbps session.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler