Results

What vxedge has measured so far, one row per hypothesis, with the caveat that matters most for each. Hypotheses are defined in ARCHITECTURE.md §2; methodology in §12. Every number below comes from a frozen summary in vxperiments/results/, which records the input manifest's sha256 alongside it. Each one is registered in FACTS.md, which also holds the full per-load and per-arm tables. This page explains the numbers; that file is where they are quoted from.

Summary

Hypothesis	Experiment	Verdict	Headline number
H1 — isolation: VLAN + tc queue-tree reservations keep ADAS p99 near baseline under infotainment load	`exp-001`	Holds	ADAS p99 at 600 mbit load: 81.9 µs vs 89.6 µs baseline (0.91×; threshold 2.0×)
H2 — real S-NSSAI slicing vs static VLAN mapping	`exp-010`	Holds	p99 growth, baseline → 600 mbit: S-NSSAI 0.95× vs VLAN 0.91× (tolerance 1.1×)
H3 — virtual-ECU packaging affects zone-to-compute latency	`exp-002` → `exp-002b`	Holds	Virtio transport is the dominant factor: MMIO → PCI Δp50 −26.0 µs (IQR 2.2 µs)
H4 — co-located OTA does not compromise the ADAS slice	`exp-003`	Holds	ADAS p50: 52.2 µs baseline vs 51.9 µs under OTA burst (Δ −0.3 µs, inside the 6.0 µs IQR)

Every campaign above is 5 repetitions per arm or load point, 1000 pps × 60 s per point (60 000 probes), with a 10 s warmup discarded. Each result has been reproduced by an independent second campaign (--repro) that reached the same verdict.

H1 — isolation (`exp-001`)

The ADAS tail does not grow with load: p99 is 89.6 µs idle and 81.9 µs at 600 mbit, and loss is 0.0 % at every level. Full table: FACTS.md § H1.

Caveat: the gateway shares its host with the zones it serves, and timestamps are taken in userspace (SO_TIMESTAMPING is a tracked follow-up). An earlier version of this campaign measured loopback delivery instead of the gateway path, because probe and reflector sat in the same network namespace. That defect was fixed with real netns isolation and is now covered by a CI regression test. The numbers above are the corrected re-run. Summary

H2 — real slicing vs static mapping (`exp-010`)

S-NSSAI PDU sessions through Open5GS + UERANSIM, compared against exp-001's VLAN arm. The S-NSSAI path has a higher absolute floor (p99 ≈ 317–337 µs, since it crosses a software UPF and GTP-U), but its tail grows no faster under load than the VLAN path does, which is what the hypothesis tests.

Caveat: the first campaign did not hold, because nothing in the 5G path applied per-slice QoS. The fix was real HTB enforcement on the slice path. We checked first whether 5QI/AMBR configuration alone would do it, and it did not change anything. The campaign was then re-run with host-noise mitigations (CPU governor, core pinning, randomized load order). All intermediate campaigns are kept in the results directory. Summary

H3 — virtualization choice (`exp-002b`)

Six packaging arms, from container to microvm-mmio, with p50/p99, CPU and RSS per arm: FACTS.md § H3.

Decomposition: virtio transport (MMIO vs PCI) −26.0 µs; libvirt vs raw QEMU −17.3 µs, likely because libvirt enables vhost/optimized virtio settings that a bare QEMU invocation does not; vhost-net alone −9.5 µs. Machine type (q35 vs microvm) has no measurable effect (−0.3 µs, within IQR).

Caveat: exp-002's original conclusion ("microVMs are slowest") was right about the ranking but wrong about the cause. exp-002b was designed specifically to separate the factors. Summary

H4 — OTA co-location (`exp-003`)

Both arms, with p50/p95/p99 and OTA deliveries (361 ok, 0 failed per repetition): FACTS.md § H4.

Caveat: the v1 OTA transport binds a plain host address. That means this measures host-level CPU and scheduling contention between OTA and the ADAS probe, not gateway-QoS-enforced network contention. A second campaign moved the absolute numbers outside the first campaign's IQR, which is session-to-session host drift, but it did not change the comparative verdict. Summary

Other completed experiments

exp-005 — cold-start / first-packet latency after zone boot. The effect was confirmed in 20 of 20 repetitions. It explains the inflated first-arm tails seen incidentally in exp-001/002/003.
exp-014 — wiring-harness topology as a variable: star vs daisy-chained zones. The expected hop-count effect holds.

Methodology caveats that apply to everything above

These are properties of the host class used for phase 1–2, not of one machine:

Shared-host gateway: vxgateway runs on the same host as the zones.
Non-PREEMPT_RT kernel, performance CPU governor, measurement cores pinned.
Userspace monotonic timestamps.

Host requirements per experiment tier are in TESTBED-SETUP.md.

Cite this page

Djaafri, F. (2026). vxedge: Results. Documentation, version 0.2.0, commit 33ede87. https://vxedge.dev/docs/RESULTS.html

@misc{djaafrivxedgeresults2026,
  author = {Djaafri, Fouzi},
  title  = {vxedge: Results},
  year   = {2026},
  url    = {https://vxedge.dev/docs/RESULTS.html},
  note   = {Documentation, version 0.2.0, source commit 33ede87}
}

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