Gahow Wang
54de78eb11
The prior write-up presented one specific reading of the data as the headline without flagging methodology gaps. Three corrections: 1. The "0% low-concurrency tax" comes from a single back-to-back mooncake_both_v2/plain_v2 rerun. The original Phase A pair showed TTFT p90 +29%, TPOT p90 +54%, E2E p90 +55% at rate=2 — a 40 percentage-point swing between two consecutive runs that the original write-up did not call out. The run-to-run noise floor is too high to claim "0%" at low concurrency. 2. get_finished() was never instrumented. The patch only times step_duration_us and build_meta_us. "100% of per-step cost is build_meta" is an upper bound on what was timed, not a true decomposition. 3. H5 (cache-size dependence) was the central hypothesis but was never tested in the prior run; random content kept APC near empty. The +7-9% high-concurrency (single instance, 512x64, rate=8-16) and +17% 8-instance-saturated numbers are kept; they were measured with adequate sample sizes and are reproducible. The follow-up sweep in cache_sweep/ tests H5 directly and revises the decomposition. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>