Files
agentic-kvc/scripts/launch_vllm.sh
Gahow Wang 05592e6adc Agentic workload PD separation analysis with trace-driven benchmarks
Systematic study of prefill-decode disaggregation for agentic LLM workloads
using production GLM-5.1 coder trace (2.1M requests, 71B input tokens).

Key findings:
- Cache-aware routing improves TPOT p90 by 15% and APC from 20.8% to 44.7%
  without PD separation, matching PD-Sep's decode isolation benefit
- PD separation adds +72% TTFT overhead (KV transfer) with no TPOT gain
  when using the same cache-aware scheduler
- Prefill remains compute-bound even at 95% KV cache reuse (AI >1000x
  vs decode AI <2), but absolute FLOPs drop 71% from cache hits
- For agentic MoE workloads, cache-aware routing > PD separation

Infrastructure:
- Trace sampler preserving session structure + hash_ids for prefix sharing
- Async trace replayer with streaming TTFT/TPOT/E2E measurement
- Unified cache-aware + token-level load-balanced global scheduler proxy
  supporting both PD-colocated and PD-disaggregated (Mooncake/RDMA) modes
- vLLM 0.18.1 scheduler patch for KV transfer abort race condition
- Roofline analysis tool for prefill/decode compute characterization

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-05-21 21:21:57 +08:00

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#!/bin/bash
# Launch vLLM 0.18.1 in PD-combined mode (TP=8, all GPUs).
#
# Usage: bash scripts/launch_vllm.sh
set -euo pipefail
SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
PROJECT_DIR="$(dirname "$SCRIPT_DIR")"
VLLM="$PROJECT_DIR/.venv/bin/vllm"
MODEL_PATH="${MODEL_PATH:-$HOME/models/Qwen/Qwen3-Coder-30B-A3B-Instruct}"
HOST="${HOST:-0.0.0.0}"
PORT="${PORT:-8000}"
echo "Starting vLLM 0.18.1 in PD-combined mode (TP=8) on port $PORT ..."
$VLLM serve "$MODEL_PATH" \
--trust-remote-code \
--enable-prefix-caching \
--dtype auto \
--tensor-parallel-size 8 \
--host "$HOST" \
--port "$PORT"