raphael
60fa164626
02 — The cast of characters: equipment, EAP, MES, fab planner, AMHS, operator. Who initiates which conversation, why the equipment is the passive side of HSMS by convention, how the AMHS handshake is out-of-band relative to SECS. Cross-references the relevant namespace and test files for each actor. 03 — Vocabulary + a wafer's journey: follows one 300 mm wafer end-to-end through a fab and labels every SECS message and acronym that fires. Introduces SVID / DVID / ECID / CEID / RPTID / ALID / PPID / MDLN / SOFTREV / HCACK / ALCD / OFLACK / CAACK / SMACK / etc. in context rather than as a list. Includes one-screen reference tables for the remaining acknowledge codes, T-timers in all four contexts (HSMS / SECS-I / E84 / E30 communication state), and a stream-by-stream summary. Part 1 (Foundations) of the guided tour is now complete — a reader who reads chapters 01–03 can describe the protocol stack, identify the actors, and recognise every acronym they'll meet in Part 2. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
70 lines
3.0 KiB
Markdown
70 lines
3.0 KiB
Markdown
# Performance baseline
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Numbers from `build/secs_bench --requests 20000 --concurrency 16` on
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Docker / Ubuntu 24.04 inside Docker Desktop on macOS (M-series), single
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io_context thread. Treat as **rough envelope for capacity planning**,
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not lab-grade benchmarks; re-run on your target hardware before
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sizing pods or VMs.
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## Round-trip throughput / latency
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| Scenario | Ops | Elapsed | Ops/sec | p50 µs | p95 µs | p99 µs |
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|----------------------------------|--------:|--------:|-----------:|--------:|--------:|--------:|
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| S1F1/F2 (header-only) | 20000 | 0.14 | ~140000 | 74 | 103 | 161 |
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| S1F3/F4 (32 SVIDs) | 20000 | 0.25 | ~79000 | 165 | 186 | 260 |
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| S6F11 push (W=0) | 20000 | 0.03 | ~572000 | n/a | n/a | n/a |
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**Read the table this way.** A real fab tool needs to handle tens to a
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few hundred S6F11 events/second sustained. We're three orders of
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magnitude above that on the push path, two orders above on synchronous
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round-trips. Throughput is not the bottleneck; latency tail under
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contention is.
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## Memory footprint
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A `ProcessJob` + `ControlJob` pair (no persistence enabled) is around
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**~450 bytes** of heap (1000 pairs ≈ 0.45 MiB, measured on a fresh
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process). With persistence enabled add ~200 bytes of in-memory journal
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path tracking per record.
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| Active entity | Approx bytes / instance |
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|----------------------|------------------------:|
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| PJ + CJ pair | ~450 |
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| Carrier (no slots) | ~80 |
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| Carrier slot | ~24 |
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| Substrate | ~120 |
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| Spool entry | ~40 + encoded body size |
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A busy fab tool tracking 50 carriers × 25 slots, 200 substrates, 20
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active PJ+CJ pairs comes in well under 1 MiB of model state. RSS will
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be dominated by the binary itself + asio's buffers (~10-20 MiB),
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not the model.
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## How to re-run
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```sh
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docker compose run --rm builder /app/build/secs_bench \
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--requests 50000 \
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--concurrency 32 \
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--svid-count 32 \
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--store-pairs 10000
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```
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Output is markdown — pipe to a file and commit it to your CI so
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regressions show up as diffs.
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## What this does NOT measure
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- **Real network**. Loopback TCP has no MTU fragmentation, no
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retransmits, no jitter. Production HSMS over a fab control LAN will
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see higher tail latency.
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- **Persistence write amplification**. The bench runs with persistence
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disabled. Each store mutation with persistence enabled is one
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atomic-rename to disk; on rotational media that limits you to a few
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hundred mutations/sec. SSD-backed deployments are fine.
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- **Concurrent S6F11 enable filtering**. Real CEID emission gates on
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the host's enable/disable list — this bench fires raw S6F11s.
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- **Multi-session HSMS-GS** dispatch overhead — single-session only.
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- **TLS-tunneled sockets** (via stunnel/sidecar) — these add ~50 µs
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per round-trip on modern hardware.
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