Commit Graph

3 Commits

Author SHA1 Message Date
2b0ac70ee7 Phase 1 milestone: system-level analysis + reproducible report
- REPORT.md: self-contained milestone report covering baseline vs elastic
  setup, exact launch commands, benchmark params, results, log locations,
  and repo structure — sufficient for anyone to reproduce
- analysis/pd_separation_analysis.md §5: elastic P2P system-level breakdown
  (KV cache hit ratio, per-class TTFT, GPU util paradox explanation)
- scripts/cache_aware_proxy.py: round-robin P-instance selection replacing
  argmin(ongoing_tokens) to fix GPU load imbalance (3.0x → expected ~2x)
- scripts/launch_elastic_p2p.sh: one-command launch for elastic P2P config

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-05-22 16:17:41 +08:00
efa70f05b5 Consolidate analysis into single report with appendix
Merged roofline_analysis.md into pd_separation_analysis.md.
Restructured as a self-contained research report:

1. TL;DR with key finding (KV cache memory wall)
2. Workload characterization (trace stats + cache reuse)
3. Experiment setup (hardware, software, configs, scripts)
4. Results (main comparison, GPU util, breakdown, ablations)
5. Analysis (DistServe assumptions, roofline, root cause)
6. Conclusions
7. Appendix: all experiment artifacts, data paths, reproducing steps

One document to read, with pointers to data for deeper analysis.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
2026-05-22 00:23:23 +08:00
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