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36 lines
1.5 KiB
Markdown
36 lines
1.5 KiB
Markdown
# Ring Benchmark Results
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Generated by `lib/erlang/bench_ring.sh` against `sx_server.exe` on the
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synchronous Erlang-on-SX scheduler.
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| N (processes) | Hops | Wall-clock | Throughput |
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|---|---|---|---|
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| 10 | 10 | 907ms | 11 hops/s |
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| 50 | 50 | 2107ms | 24 hops/s |
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| 100 | 100 | 3827ms | 26 hops/s |
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| 500 | 500 | 17004ms | 29 hops/s |
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| 1000 | 1000 | 29832ms | 34 hops/s |
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(Each `Nm` row spawns N processes connected in a ring and passes a
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single token N hops total — i.e. the token completes one full lap.)
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## Status of the 1M-process target
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Phase 3's stretch goal in `plans/erlang-on-sx.md` is a million-process
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ring benchmark. **That target is not met** in the current synchronous
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scheduler; extrapolating from the table above, 1M hops would take
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~30 000 s. Correctness is fine — the program runs at every measured
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size — but throughput is bound by per-hop overhead.
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Per-hop cost is dominated by:
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- `er-env-copy` per fun clause attempt (whole-dict copy each time)
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- `call/cc` capture + `raise`/`guard` unwind on every `receive`
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- `er-q-delete-at!` rebuilds the mailbox backing list on every match
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- `dict-set!`/`dict-has?` lookups in the global processes table
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To reach 1M-process throughput in this architecture would need at
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least: persistent (path-copying) envs, an inline scheduler that
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doesn't call/cc on the common path (msg-already-in-mailbox), and a
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linked-list mailbox. None of those are in scope for the Phase 3
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checkbox — captured here as the floor we're starting from.
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