gahow/aituner
0
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Record fixed PD pressure calibration result

Browse Source
This commit is contained in:
Gahow Wang
2026-07-19 01:45:17 +08:00
parent 33b73afe9b
commit 7ea9635878
1 changed files with 35 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

37
runs/frontier-fidelity-envelope-v1/fixed-pd-pressure-matching-card.md
View File

@@ -1,7 +1,7 @@
# EXP-SIMFID-Q30-FIXED-PD-PRESSURE: calibrate a nontrivial fixed-shape workload
> Status: planned. This is a real-only workload calibration; its measurements
> are not part of a Frontier-versus-vLLM winner comparison.
> Status: complete (2026-07-19). This is a real-only workload calibration; its
> measurements are not part of a Frontier-versus-vLLM winner comparison.
## Question
@@ -54,3 +54,36 @@ This selects a workload regime, not a simulator parameter and not a serving
capacity point. It may make Fixed-PD more comparable to Trace-PD in batching
pressure, but it deliberately continues to exclude trace-shaped arrivals and
prefix reuse; those are separately evaluated workload dimensions.
## Result
All 12 planned cells completed (`257` requests × `3` fresh-server trials per
rate, zero client failures). The raw artifact is
`dash0:/home/admin/cpfs/wjh/aituner/qwen30-fixed-pd-pressure-20260719-r5`;
it records the vLLM version, model/config checksums, H20 inventory, FlashInfer
workspace, and an artifact checksum manifest. Pooled results are:
| Global / per-GPU rps | TTFT mean / p90 (ms) | TPOT mean / p90 (ms) | E2E mean / p90 (ms) | In-flight proxy |
|---|---:|---:|---:|---:|
| 4 / 1 | 121.53 / 125.12 | 10.75 / 11.83 | 2862.42 / 3138.92 | 11.45 |
| 4.5 / 1.125 | 122.76 / 126.29 | 11.76 / 12.55 | 3122.32 / 3322.26 | 14.05 |
| 5 / 1.25 | 125.09 / 129.66 | 15.16 / 16.58 | 3989.73 / 4354.22 | 19.95 |
| 6 / 1.5 | 129.27 / 134.69 | 21.33 / 23.03 | 5569.14 / 6005.12 | 33.41 |
The predeclared two-metric rule picks `4.5` global rps (`1.125` rps/GPU), but
that is only the *least mismatched* tested point: TTFT is still 50.1% below
the Trace-PD target (122.76 vs 245.95 ms), while TPOT is 10.7% below it (11.76
vs 13.18 ms). Raising load to 5 global rps moves TPOT past target (+15.0%)
while TTFT barely changes (125.09 ms); at 6 global rps TPOT is +61.9% while
TTFT remains 47.4% below target. Trial-level mean standard deviations are at
most 0.78 ms for TTFT and 0.34 ms for TPOT, so this is not trial-order noise.
**Conclusion:** `4096 -> 256` with uniform no-prefix arrivals cannot be called
a pressure-matched Fixed-PD control simply by setting RPS. It has much shorter
request residence time (3.12 s versus 44.99 s) and lower concurrency (14.05
versus 38.69 by the same Little-law proxy) at its closest point. For the
paper's fixed-versus-trace comparison, retain this case only as a deliberately
different fixed-shape workload; do not interpret any simulator gap as being
caused solely by trace fidelity. A future pressure-matched fixed control must
also increase output length (or otherwise preserve residence time), then repeat
this real-only calibration before reopening the Frontier-versus-vLLM surface.