Surfaces four boot-race latency metrics as a structured JSON
endpoint at /scheme/driver-manager/timing, plus a per-bucket
p50/p95/p99 summary line appended to /tmp/redbear-boot-timeline.json.
The four metric buckets:
- claim-spawn: time from probe to child daemon ready (wraps the
config.rs::probe() spawn path).
- firmware-ready: time from NEED_FIRMWARE quirk consultation to
/scheme/firmware/ registering the needed blob. Also: devices
with firmware now bind immediately when the scheme is present
(previously always deferred) - correct behavior, not a workaround.
- governor-switch: time from thermald writing /scheme/cpufreq/governor
to cpufreqd applying the new governor (v5.1 wired this path;
bucket is defined but population is in cpufreqd's scope).
- aer-event: pcid->consumer latency parsed from pcid's
'ts=<rfc3339>' field embedded in each event line.
Architecture:
- timing.rs (NEW): LatencyMetric, Bucket with lock-free AtomicU64
counters (fetch_min/fetch_max/fetch_update), percentile samples
in Mutex<Vec<u64>> capped at 4096 per bucket, RFC3339 parser
that handles epoch seconds, fractional seconds, trailing Z, and
colon-collision with pcid's key=value field separators.
- config.rs: wraps spawn path with Instant::now()/elapsed timing
guard; firmware-available scheme check before deferring.
- unified_events.rs: AER consumer records pcid->consumer latency
by parsing ts= field from the event line.
- scheme.rs: new Timing handle kind, /scheme/driver-manager/timing
path returns JSON snapshot on every read, root listing updated.
- main.rs: log_timing_snapshot() appends per-bucket p50/p95/p99 to
boot timeline after enumeration completes (skipped in initfs).
Output format (read via 'cat /scheme/driver-manager/timing'):
{
"version": 1,
"buckets": {
"claim-spawn": { "count": 17, "min_us": ..., ... },
"firmware-ready": { ... },
"governor-switch": { ... },
"aer-event": { ... }
}
}
Tests: 24 new (single record, 100-record percentile ordering,
empty bucket, 8-thread × 500 concurrent records, JSON golden
snapshots, ring buffer capping, percentile index math, RFC3339
parsing variants, civil-to-days algorithm, firmware-defer
lifecycle). Total 112 tests pass, 0 failed.
Compile: cargo check --target x86_64-unknown-redox - zero new
warnings (only pre-existing libredox FFI warnings remain).
Constraints per local/AGENTS.md:
- No new branches (work on 0.3.1)
- No new Cargo dependencies (std-only: AtomicU64, Mutex, Vec, etc.)
- No stubs, no todo!/unimplemented!
- Cat 1 in-house recipe - source IS the durable location
Closes v5.5 of the v5.x work program.
kellito
045aaa4579