aggregate_mb5.py:
- Split the cluster KV timeline by role (P-pool vs D-pool) using a
PID->role map parsed from vllm_logs filenames. The cluster average
hid the result — 6P+2D/4P+4D look ~45% utilized but the decode pool
is actually pegged at ~100% while prefill idles at ~30%.
- Two-stage reduce/plot: --reduce-to (numpy-only, runs on the serving
host over multi-GB snapshot dirs) dumps a compact JSON; --from-reduced
(matplotlib) renders locally. matplotlib import is now lazy.
- New plot_role_split figure + p/d peak/steady columns in the CSV.
PD_DISAGG_RESULTS.md: consolidated writeup with figures inline.
Verdict: no static P:D ratio beats 8C colocation. The binding
constraint moves with the ratio (D-pool saturates at 6P+2D/4P+4D,
P-pool jams at 2P+6D -> 91% request loss); 8C's shared pool stays
elastic at 34% steady, 100% completion. PD wins TPOT (10-35x cleaner,
the MB1 phase-isolation benefit is real) but loses TTFT and sheds
load. Round-robin P routing also zeroes prefix-cache reuse; a
session-affinity re-run of 6P+2D is in flight to test the fix.
Figures (rep1): mb5_kv_timeline, mb5_role_split, mb5_peak_utilization,
mb5_latency_compare + mb5_summary.csv.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Gahow Wang
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