c9d350b372
Document the iterative debugging from v1 (broken KVC) through v4
(routing fixed + session cap raised), with code-level analysis of
the two main bugs encountered:
1. v2 root cause (mis-diagnosed previously as `allow_local_prefill`):
`--policy default` for KVC mechanism caused replay's round-robin
policy and the PD router's round-robin to diverge, sending requests
with `session_params` to a D worker that did not have the session
open. Resulted in 56-61% truncation with finish_reason
"session id X does not exist".
Fix: use `--policy kv-aware` (sweep_tp1_v3_kvaware.sh) so replay
emits `x-smg-target-worker` and PD router uses consistent_hashing.
2. v3 new bottleneck: `pd-router-fallback-large-append-session-cap`
dominated 52-65% of requests. Root cause was hardcoded
`min(4, ...)` in `_decode_session_soft_cap`. With 7 D workers x 4
sessions = 28 slots for 52 trace sessions, ~24 sessions starved
permanently (bimodal direct-to-D rate of 0% or 99%).
Fix: raise the cap to 16 (replay.py).
Also includes the v3 finding that direct-to-d-session path P50=0.495s
and TTFT P50=0.043s already beats the 8-way DP baseline (0.65s/0.093s)
- the KVC core mechanism works when fallback paths are avoided.
Files:
- docs/KVC_DEBUG_JOURNEY_V1_TO_V4.md: full journey + code location index
- docs/SWEBENCH_EXPERIMENT_{PROGRESS,RESULTS}.md: prior session notes
- scripts/sweep_tp1_v{2,3,4}*.sh: experiment driver scripts
- src/agentic_pd_hybrid/replay.py: cap 4 -> 16, audit fields
- src/agentic_pd_hybrid/pd_router.py: strip session_params from prefill
- src/agentic_pd_hybrid/metrics.py: truncated_request_count
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
25 lines
805 B
Bash
Executable File
25 lines
805 B
Bash
Executable File
#!/bin/bash
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# Experiment A: pd-disaggregation baseline
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# 1P(GPU 0-3) + 1D(GPU 4-7), TP4, mooncake TCP
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# Full 39K trace from SWE-Bench 500 instances
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set -euo pipefail
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cd "$(dirname "$0")/.."
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uv run agentic-pd-hybrid benchmark-live \
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--trace outputs/qwen35-swebench-500.jsonl \
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--output-root outputs/swebench-exps \
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--mechanism pd-disaggregation \
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--policy default \
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--model-path /mnt/kzlin/workflow/pd-hybrid/simm-swe-bench/models/Qwen3.5-35B-A3B \
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--prefill-workers 1 --decode-workers 1 \
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--prefill-tp-size 4 --decode-tp-size 4 \
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--prefill-gpu-ids 0,1,2,3 --decode-gpu-ids 4,5,6,7 \
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--transfer-backend mooncake \
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--gpu-budget 8 \
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--time-scale 10 \
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--session-sample-rate 1.0 \
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--target-duration-s 100000 \
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--concurrency-limit 64 \
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--timeout-s 900 \
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--request-timeout-s 300
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