Files
agentic-pd-hybrid/scripts/sweep_tp1_v3_kvaware.sh
kzlin c9d350b372 docs: KVC v1-v4 debug journey + raise session soft_cap to 16
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>
2026-04-28 21:10:41 +08:00

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#!/bin/bash
# TP1 v3 sweep — KVC with kv-aware policy (fix routing mismatch)
# v2 used --policy default for KVC experiments, causing session routing
# mismatch: replay round-robin ≠ router round-robin → "session not found".
# v3 uses --policy kv-aware for KVC to ensure session affinity.
set -euo pipefail
cd "$(dirname "$0")/.."
MODEL=/mnt/kzlin/workflow/pd-hybrid/simm-swe-bench/models/Qwen3-30B-A3B-Instruct-2507
TRACE=outputs/qwen35-swebench-50sess.jsonl
OUTPUT=outputs/qwen3-30b-tp1-v3-kvaware
VENV_PYTHON=.venv/bin/python
RESULTS_FILE=$OUTPUT/sweep_results.txt
mkdir -p $OUTPUT
log() {
echo "[$(date '+%Y-%m-%d %H:%M:%S')] $*" | tee -a $RESULTS_FILE
}
save_result() {
local label=$1
local run_dir=$2
log "=== $label COMPLETED ==="
if [ -f "$run_dir/request-metrics.jsonl.summary.json" ]; then
log "Summary:"
cat "$run_dir/request-metrics.jsonl.summary.json" >> $RESULTS_FILE
echo "" >> $RESULTS_FILE
cp "$run_dir/request-metrics.jsonl.summary.json" "$OUTPUT/${label}_summary.json"
cp "$run_dir/request-metrics.jsonl" "$OUTPUT/${label}_metrics.jsonl"
log "Saved to $OUTPUT/${label}_summary.json + ${label}_metrics.jsonl"
else
log "WARNING: No summary file found in $run_dir"
fi
}
log "Starting TP1 v3 sweep (KVC with kv-aware policy)"
log "Model: $MODEL"
log "Trace: $TRACE (4449 requests, 52 sessions)"
log "Key change: --policy kv-aware for KVC (was --policy default in v2)"
########################################
# Experiment 1: 1P + 7D KVC kv-aware
########################################
log ""
log "=== [EXP1] 1P7D KVC kv-aware ==="
PYTHONPATH=src:third_party/sglang/python \
$VENV_PYTHON -m agentic_pd_hybrid.cli benchmark-live \
--trace $TRACE \
--output-root $OUTPUT \
--mechanism kvcache-centric \
--policy kv-aware \
--model-path $MODEL \
--prefill-workers 1 --decode-workers 7 \
--prefill-tp-size 1 --decode-tp-size 1 \
--prefill-gpu-ids 0 --decode-gpu-ids 1,2,3,4,5,6,7 \
--transfer-backend mooncake \
--gpu-budget 8 \
--time-scale 10 \
--session-sample-rate 1.0 \
--target-duration-s 100000 \
--concurrency-limit 32 \
--timeout-s 900 \
--request-timeout-s 300 \
--kvcache-admission-mode worker \
--kvcache-seed-min-turn-id 1 \
--kvcache-seed-max-inflight-decode -1 \
--kvcache-prefill-backup-policy release-after-transfer \
--kvcache-prefill-priority-eviction
EXP1_DIR=$(ls -td $OUTPUT/kvcache-centric-*/ 2>/dev/null | head -1)
save_result "exp1_1p7d_kvc_kvaware" "$EXP1_DIR"
########################################
# Experiment 2: 2P + 6D KVC kv-aware
########################################
log ""
log "=== [EXP2] 2P6D KVC kv-aware ==="
PYTHONPATH=src:third_party/sglang/python \
$VENV_PYTHON -m agentic_pd_hybrid.cli benchmark-live \
--trace $TRACE \
--output-root $OUTPUT \
--mechanism kvcache-centric \
--policy kv-aware \
--model-path $MODEL \
--prefill-workers 2 --decode-workers 6 \
--prefill-tp-size 1 --decode-tp-size 1 \
--prefill-gpu-ids 0,1 --decode-gpu-ids 2,3,4,5,6,7 \
--transfer-backend mooncake \
--gpu-budget 8 \
--time-scale 10 \
--session-sample-rate 1.0 \
--target-duration-s 100000 \
--concurrency-limit 32 \
--timeout-s 900 \
--request-timeout-s 300 \
--kvcache-admission-mode worker \
--kvcache-seed-min-turn-id 1 \
--kvcache-seed-max-inflight-decode -1 \
--kvcache-prefill-backup-policy release-after-transfer \
--kvcache-prefill-priority-eviction
EXP2_DIR=$(ls -td $OUTPUT/kvcache-centric-*/ 2>/dev/null | head -1)
save_result "exp2_2p6d_kvc_kvaware" "$EXP2_DIR"
########################################
log ""
log "=== ALL TP1 V3 SWEEP EXPERIMENTS DONE ==="