--policy leastwork_kappa + --kappa (default 2.5e-6, derived from KV ~100KB/tok
/ HBM 4TB/s / TPOT 10ms on H20+Qwen3-30B-A3B): score = prefill_work * (1 +
kappa * ongoing_decode_tokens), modelling decode as a fractional throughput tax
on a new prefill.
Result on the 600s trace: NET-NEGATIVE vs plain leastwork — TTFT p90 +18%,
E2E p90 +14%, balance 1.55x->1.97x, and it does NOT fix the E2E-p99 it targeted.
Decode is too cheap in agentic (output p50~80) for the term to help; it just
bounces heavy reqs off their cache-owner into cold re-prefill. The E2E-p99 tail
is the structural HEAVY+>50k floor (per-class p99 ~51-52k for ALL policies), not
decode interference. Kept in-tree as a documented ablation justifying LPWL's
omission of any decode term; do not revive without a decode-heavy regime.
See analysis/lpwl_5policy_600s.md.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
traces/w600_r0.0015_st30_first600s.jsonl: first-600s cut of the shipped w600
trace (807 reqs, 274 sessions, all turn-1s + early later-turns; theoretical
APC ceiling ~70% vs 80% full). Faster iteration (~18 min/arm) but a colder,
lower-locality regime; whitelisted alongside the parent anonymized trace.
analysis/lpwl_5policy_600s.md: LPWL vs LMetric/sticky/unified/unified+A+B on
the 600s trace (dash1 8xH20, cold APC, n=1). LPWL is overall best with zero
knobs — TTFT p90 7983ms vs tuned A+B 11562 (-31%), E2E p90 -16%, best request
balance; APC 0.648 (emergent affinity, far above LMetric 0.507); only loss is
E2E p99 from heavy-class decode concentration. Demonstrates anti-overfit: A+B
was tuned on full w600 yet is beaten by the knob-free policy on this regime.
Includes the run_5policy_600s.sh repro driver.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
