joule-contrib: an SRT sender probes a stalled tail, so a lost newest packet is recovered #503

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dcharlot merged 2 commits from fix/srt-close-after-drain into main 2026-10-26 22:57:27 -04:00

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dcharlot commented 2026-10-26 20:56:10 -04:00

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An SRT sender now probes a stalled tail. Live-contribution §4.1 and the changelog say so.

A receiver finds a gap only when a later packet arrives. So if the newest packet is lost, nothing asks for it, and the sender held it until it expired. CI's linux-arm64 leg failed an_srt_publisher_reaches_a_relay_subscriber_with_every_receipt on #499 this way.

When the acknowledged position has not moved for 2 × RTT + 20 ms, and the newest packet held went out that long ago, the sender sends that packet again with the R flag set. The wait doubles with each probe, to at most 16 times the first, and resets when an ACK removes a packet.

SendCounts gains two fields:

• probes, counted separately from retransmitted, which still means retransmissions in answer to requests;
• unacknowledged, for SRT only.

The test now closes the publisher once nothing is unacknowledged. It also requires expired == 0, and its end-code assertion prints the code it read.

Evidence (Framework box, x86_64 Linux)

Run	Result
main, four instances at once on two cores	4 of 32 failed: the gateway's parts covered 107 of the 108 sequence numbers sent, and the sender read expired: 1
main, alone or four at once without pinning	60 of 60 passed
this branch, four at once on two cores	48 of 48 passed
this branch with the probe disabled (falsification)	2 of 24 failed with the same signature

The job's own commands all pass:

Command	Tests
cargo test -p joule-contrib --all-targets	30
the same with --features rist	43
cargo test -p joule-moq-ingest --all-targets	73
the same with --features rist	75

The link-vector corpus check passes (101 files). Clippy reports nothing in the changed files. The comparative-prose, vanity, spec-refs and section-refs checks pass.

🤖 Generated with Claude Code

## What An SRT sender now probes a stalled tail. Live-contribution §4.1 and the changelog say so. A receiver finds a gap only when a later packet arrives. So if the newest packet is lost, nothing asks for it, and the sender held it until it expired. CI's linux-arm64 leg failed `an_srt_publisher_reaches_a_relay_subscriber_with_every_receipt` on #499 this way. When the acknowledged position has not moved for 2 × RTT + 20 ms, and the newest packet held went out that long ago, the sender sends that packet again with the R flag set. The wait doubles with each probe, to at most 16 times the first, and resets when an ACK removes a packet. `SendCounts` gains two fields: - `probes`, counted separately from `retransmitted`, which still means retransmissions in answer to requests; - `unacknowledged`, for SRT only. The test now closes the publisher once nothing is unacknowledged. It also requires `expired == 0`, and its end-code assertion prints the code it read. ## Evidence (Framework box, x86_64 Linux) | Run | Result | |---|---| | main, four instances at once on two cores | 4 of 32 failed: the gateway's parts covered 107 of the 108 sequence numbers sent, and the sender read `expired: 1` | | main, alone or four at once without pinning | 60 of 60 passed | | this branch, four at once on two cores | 48 of 48 passed | | this branch with the probe disabled (falsification) | 2 of 24 failed with the same signature | The job's own commands all pass: | Command | Tests | |---|---| | `cargo test -p joule-contrib --all-targets` | 30 | | the same with `--features rist` | 43 | | `cargo test -p joule-moq-ingest --all-targets` | 73 | | the same with `--features rist` | 75 | The link-vector corpus check passes (101 files). Clippy reports nothing in the changed files. The comparative-prose, vanity, spec-refs and section-refs checks pass. 🤖 Generated with [Claude Code](https://claude.com/claude-code)

dcharlot added 2 commits 2026-10-26 20:56:10 -04:00

joule-contrib: count what an SRT sender holds unacknowledged; the SRT ingest test closes after the drain ... 260566dce1

an_srt_publisher_reaches_a_relay_subscriber_with_every_receipt closed the
publisher a fixed 800 ms after its last frame. On a loaded host a loss on the
3%-lossy path was still unrecovered then: the gateway counted 107 of 108
payloads delivered and one outstanding (4 failures in 32 runs, four at a time
on two cores; CI's linux-arm64 leg failed it on #499). The sender now keeps
`SendCounts::unacknowledged` (SRT; RIST acknowledges nothing and leaves it 0),
and the test closes once it is 0. The end-code assertion now says which code
it read.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

joule-contrib: an SRT sender probes a stalled tail; live-contribution §4.1 says so ... 1fd0322436

A receiver finds a gap only behind a later arrival, so a lost newest packet
went unrecovered until the sender expired it. Under contention (four at a
time on two cores) an_srt_publisher_reaches_a_relay_subscriber_with_every_receipt
failed 4 of 32 and 17 of 48: the sender's counts read expired=1 and the
gateway's parts covered 107 of the 108 sequence numbers sent. CI's
linux-arm64 leg failed the same test on #499.

When the acknowledged position has not moved for 2 x RTT + 20 ms and the
newest packet held went out that long ago, the sender sends it again with
the R flag, the wait doubling per probe to 16 times the first, reset when an
ACK takes a packet. SendCounts::probes counts them apart from retransmitted,
which answers requests. The test now also requires that the publisher gave
nothing up (expired == 0).

Co-Authored-By: Claude Opus 5.5 <[email protected]>

dcharlot merged commit 7a7edc58d0 into main 2026-10-26 22:57:27 -04:00

dcharlot referenced this pull request from a commit 2026-10-26 22:57:28 -04:00

Merge pull request 'joule-contrib: an SRT sender probes a stalled tail, so a lost newest packet is recovered' (#503) from fix/srt-close-after-drain into main

dcharlot referenced this pull request 2026-10-26 23:00:08 -04:00

wai: the developer's path (hello, create, dev, verify), the floor with no system library, nine examples, and the quickstart archive #504

dcharlot referenced this pull request 2026-10-26 23:00:18 -04:00

wai: the developer's path (hello, create, dev, verify), the floor with no system library, nine examples, and the quickstart archive #502

dcharlot referenced this pull request 2026-10-27 07:39:04 -04:00

joule-contrib: a retransmission of a packet not yet seen is recovered; the SRT tests count the first sends lost #510

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Transaction-Science/open-standards!503

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