nx_linkqual.nx

buildroot/runtime/nx_linkqual.nx

12417 B305 linesdepth 2pulls 2 transitivereach 7 importersview sourcekind librarytopic linkqual

docs dependencies structs consts functions

about

nx_linkqual.nx -- ONE sovereign real-time LINK-QUALITY substrate that improves GAME MULTIPLAYER, VIDEO ROOMS, and STREAMING from a single per-flow metrics core. Integer-only (no float), pure/deterministic (fed timestamped sample events -> KAT-able offline), raw-syscall-only (imports only nx_syscalls), zero external/licensed deps. Research-grounded (workflow wf_5c50a76d) in the canonical RFCs, all re-implemented from the SPEC (concepts, not code): - RTT smoothing: RFC 6298 / Jacobson-Karels (SRTT*8, RTTVAR*4, RTO). - Interarrival jitter: RFC 3550 A.8 (J += (|D|-J)/16, pre-scaled *16). - Loss fraction: RFC 3550 A.3 (expected-vs-received, Q16.16 fraction). - Throughput EWMA (BBR-style delivery-rate, gain 1/8). - Latency quantiles: HDR-style power-of-two magnitude buckets + a first-class max (Tene: never discard the tail -- that IS the signal). SUPERSEDES nx_bandwidth_meter for real-time use (adds jitter, quantiles, proper RTTVAR/RTO it lacks); pairs with nx_adaptive_bitrate for tiers. Consumers (the products): lq_game_advise (rollback input-delay frames), lq_jitter_buffer_ms (video-room NetEQ-style target), lq_bitrate_decision (streaming ABR up/hold/down), lq_score + lq_verdict_band (easy-for- anyone Excellent/Good/Fair/Poor + one number). Constants are bootstrap defaults destined for svc-config (CLAUDE.md 11). license_tier: ORIGINAL

dependencies 1 imports · 4 importers

imports: nx_syscalls.nx

imported by: nx_linkqual_bench.nxnx_linkqual_cycles.nxnx_linkqual_test.nxnx_mediapath.nx

structs

40	struct LinkFlow
72	struct GameAdvice { delay_frames: i64, score: i64, verdict: i64 }

consts

27	const LQ_MAGIC_32768: i64 = 32768
28	const LQ_MAGIC_65536: i64 = 65536
30	const LQ_NBUCKETS: i64 = 32
31	const LQ_SRTT_SH: i64 = 3 // SRTT stored *8
32	const LQ_RTTVAR_SH: i64 = 2 // RTTVAR stored *4
33	const LQ_JIT_SH: i64 = 4 // jitter stored *16 (RFC 3550 A.8)
34	const LQ_RATE_SH: i64 = 3 // throughput EWMA gain 1/8
35	const LQ_Q16: i64 = 16 // Q16.16 fixed-point shift (loss fraction)
36	const LQ_RTO_MIN_MS: i64 = 200 // (RFC6298 says 1000; 200 fits real-time UDP)
37	const LQ_RTO_MAX_MS: i64 = 60000
58	const LQ_FLOW_HDR_BYTES: i64 = 128
59	const LQ_FLOW_BYTES: i64 = 384
62	const LQ_EXCELLENT: i64 = 0
63	const LQ_GOOD: i64 = 1
64	const LQ_FAIR: i64 = 2
65	const LQ_POOR: i64 = 3
68	const LQ_PROD_GAME: i64 = 0
69	const LQ_PROD_VIDEO: i64 = 1
70	const LQ_PROD_STREAM: i64 = 2
73	const LQ_GAME_ADVICE_BYTES: i64 = 24

functions

75	func lq_flow_new() -> *LinkFlow called by 5: main main main mpt_flow mk_flow calls 1: sys_mmap
83	func lq_on_rtt(f: *LinkFlow, r_ms: i64) -> i64 called by 3: main main main
103	func lq_srtt_ms(f: *LinkFlow) -> i64 { return f.srtt_x8 >> LQ_SRTT_SH } called by 5: lq_score lq_game_advise lq_bitrate_decision lq_render main
104	func lq_rttvar_ms(f: *LinkFlow) -> i64 { return f.rttvar_x4 >> LQ_RTTVAR_SH } called by 1: main
107	func lq_on_arrival(f: *LinkFlow, send_ts: i64, recv_ts: i64) -> i64 called by 3: main main main
124	func lq_jitter_ms(f: *LinkFlow) -> i64 { return f.jitter_x16 >> LQ_JIT_SH } called by 5: lq_score lq_game_advise lq_jitter_buffer_ms lq_render main
127	func lq_on_seq(f: *LinkFlow, seq: i64) -> i64 called by 3: main main main
134	func lq_loss_tick(f: *LinkFlow) -> i64 called by 1: main
148	func lq_loss_pct(f: LinkFlow) -> i64 { return (f.loss_frac_q16 100 + LQ_MAGIC_32768) >> LQ_Q16 } called by 5: lq_score lq_jitter_buffer_ms lq_bitrate_decision lq_render main
151	func lq_on_delivery(f: *LinkFlow, bytes: i64, interval_ms: i64) -> i64
160	func lq_buckets(f: LinkFlow) -> i64 { return ((f as i64) + LQ_FLOW_HDR_BYTES) as *i64 } called by 2: lq_record_latency lq_quantile_ms
164	func lq_bucket_of(lat_ms: i64) -> i64 called by 1: lq_record_latency
173	func lq_record_latency(f: *LinkFlow, lat_ms: i64) -> i64 called by 3: main main main calls 2: lq_buckets lq_bucket_of
182	func lq_quantile_ms(f: *LinkFlow, p: i64) -> i64 called by 2: lq_bitrate_decision main calls 1: lq_buckets
198	func lq_score(f: *LinkFlow) -> i64 called by 7: lq_game_advise lq_render main mp_select_best mp_decide main+1 calls 3: lq_srtt_ms lq_jitter_ms lq_loss_pct
215	func lq_verdict_band(score: i64) -> i64 called by 4: lq_game_advise lq_render main mp_render
225	func lq_game_advise(f: LinkFlow, fps: i64, out: GameAdvice) -> i64 called by 2: lq_render main calls 4: lq_srtt_ms lq_jitter_ms lq_score lq_verdict_band
241	func lq_jitter_buffer_ms(f: *LinkFlow) -> i64 called by 2: lq_render main calls 2: lq_jitter_ms lq_loss_pct
254	func lq_bitrate_decision(f: *LinkFlow) -> i64 called by 2: lq_render main calls 3: lq_loss_pct lq_quantile_ms lq_srtt_ms
265	func lq_band_word(b: i64) -> i64 called by 2: lq_render mp_render calls 1: sys_write
272	func lq_dec(n: i64) -> i64 called by 2: lq_render mp_render calls 2: sys_write sys_mmap
283	func lq_render(f: *LinkFlow, product: i64) -> i64 called by 1: main calls 12: lq_score sys_write lq_band_word lq_verdict_band lq_dec lq_srtt_ms+6