AdGuard Home on port 5457, both forwarding via DoH. Cached queries
tied at 0.1ms. On degraded networks hedging hurts p99 (28ms vs 10ms
without) — both requests pay the same high RTT with no random spikes
to rescue. On clean networks hedging wins.
With ROUNDS=10, only the first query per domain was truly cold — the
other 9 hit cached NS delegations at <1ms, diluting the median to
0.4ms. Now cold mode uses 1 round so every sample is a real cold
resolve. Also extracted compare_two_rounds to support per-mode rounds.
Re-runs of --vs-unbound-cold were hitting stale cache entries from
prior runs. The static COUNTER reset to 0 each process, generating
the same c0.example.com subdomains. With the 1-hour stale window,
entries from 10 minutes ago served as stale hits.
Fix: prefix with PID (r{pid}-c{n}.domain) and flush Numa's cache
before cold benchmarks.
- --vs-nextdns: Numa local cache vs NextDNS cloud (45.90.28.0)
- --vs-unbound-cold: unique random subdomains, no record cache hits
- check_numa_mode validates forward/recursive mode before running
- numa-bench-recursive.toml config for cold benchmarks
Wire-level forwarding path skips DnsPacket parse/serialize on the hot
path. Cache stores raw wire bytes with pre-scanned TTL offsets — patches
ID + TTLs in-place on lookup instead of cloning parsed packets.
Request hedging (Dean & Barroso "Tail at Scale") fires a second
parallel request after a configurable delay (default 10ms) when
the primary upstream stalls. DoH keepalive loop prevents idle
HTTP/2 + TLS connection teardown.
Recursive resolver now hedges across multiple NS addresses and
caches NS delegation records to skip TLD re-queries.
Integration test harness polls /blocking/stats instead of fixed
sleep, eliminating the blocklist-download race condition.
