Index hierarchical machine configuration

[SandroMaglione]

Summary

• compile eligible compound and parallel machines into numeric topology and per-leaf event dispatch tables
• retain active values and completion metadata in a compact indexed configuration while draining, materializing public snapshots only at process boundaries
• preserve general-planner fallback semantics and add explicit compiled-hierarchy resume coverage

Changeset

• Added or updated for a library or package-metadata change
• Not required because this PR does not change src/ or package.json

Validation

• pnpm check
• Relevant example checks, when examples changed (not applicable)
• Reviewed the automated type-performance report, when the public TypeScript API or inference changed (no public type change; pnpm perf:types passes)
• Reviewed the automated runtime-performance report, when runtime behavior changed

Local five-process interleaved base-versus-branch validation found +21.5% compound throughput and +22.8% parallel throughput, with unchanged measured heap profiles and unrelated runtime metrics within noise.

[github-actions]

Type performance

Measured with TypeScript 6.0.3 and skipLibCheck=true.

Scenario	Base	PR	Difference
Effect only	55	55	0 (0.0%)
Import effect-machine	55	55	0 (0.0%)
Machine.defineStates (3 states)	2,965	2,965	0 (0.0%)
Machine.make (3 states, 2 events)	8,715	8,715	0 (0.0%)
machine.handle (3 states, 2 transitions)	23,492	23,492	0 (0.0%)
machine.handle (depth 8)	117,075	117,075	0 (0.0%)
machine.handle (depth 12)	129,713	129,713	0 (0.0%)
machine.handle (depth 16)	145,055	145,055	0 (0.0%)
machine.handle (depth 24)	183,851	183,851	0 (0.0%)
machine.handle (wide depth 16)	214,189	214,189	0 (0.0%)
machine.handle (parallel/history/choice)	132,667	132,667	0 (0.0%)
machine.handle (4 successive calls)	128,674	128,674	0 (0.0%)
machine exact input/output/error/services	110,584	110,584	0 (0.0%)
execution adapter readiness	127,854	127,854	0 (0.0%)

Marginal instantiations are measured against the matching setup without that API call:

Scenario	Base	PR	Difference
Import effect-machine	0	0	0
Machine.defineStates (3 states)	2,910	2,910	0 (0.0%)
Machine.make (3 states, 2 events)	5,742	5,742	0 (0.0%)
machine.handle (3 states, 2 transitions)	14,777	14,777	0 (0.0%)
machine.handle (depth 8)	109,601	109,601	0 (0.0%)
machine.handle (depth 12)	121,039	121,039	0 (0.0%)
machine.handle (depth 16)	135,181	135,181	0 (0.0%)
machine.handle (depth 24)	171,577	171,577	0 (0.0%)
machine.handle (wide depth 16)	202,224	202,224	0 (0.0%)
machine.handle (parallel/history/choice)	114,331	114,331	0 (0.0%)
machine.handle (4 successive calls)	113,703	113,703	0 (0.0%)
machine exact input/output/error/services	100,670	100,670	0 (0.0%)
execution adapter readiness	102,092	102,092	0 (0.0%)

Check times (informational)

Scenario	Base	PR
Effect only	0.03s	0.03s
Import effect-machine	0.03s	0.03s
Machine.defineStates (3 states)	0.10s	0.10s
Machine.make (3 states, 2 events)	0.16s	0.16s
machine.handle (3 states, 2 transitions)	0.22s	0.23s
machine.handle (depth 8)	0.51s	0.52s
machine.handle (depth 12)	0.57s	0.55s
machine.handle (depth 16)	0.60s	0.62s
machine.handle (depth 24)	0.70s	0.70s
machine.handle (wide depth 16)	0.76s	0.80s
machine.handle (parallel/history/choice)	0.63s	0.63s
machine.handle (4 successive calls)	0.60s	0.58s
machine exact input/output/error/services	0.53s	0.53s
execution adapter readiness	0.57s	0.56s

Type instantiations are the comparison metric. Check time varies with runner load and is informational only.

[github-actions]

Runtime performance

Median of 5 independent benchmark processes on AMD EPYC 7763 64-Core Processor with Node v24.18.0.

Pull request baseline

Scenario	Effect Machine	XState 5	XState 6 alpha
Plan counter transitions	119,077 transitions/s	132,933 transitions/s	121,080 transitions/s
Drain burst with terminal fence	231,993 increments/s	389,442 increments/s	110,684 increments/s
Drain burst with a change observer	152,323 increments/s	386,984 increments/s	110,058 increments/s
Lookup and send to one child	199,989 increments/s	384,544 increments/s	105,442 increments/s
Start and stop a machine	26,532 machines/s	186,220 machines/s	72,537 machines/s
Start and stop a parent with one child	9,351 families/s	69,314 families/s	26,617 families/s
Drain burst through a compound state	291,019 events/s	342,772 events/s	109,155 events/s
Drain burst through two parallel regions	273,549 events/s	259,159 events/s	91,694 events/s

Effect runtime reference points

Scenario	Effect Machine	Effect runtime primitives
Start and stop a raw compiled process	34,716 processes/s	—
Start and interrupt a suspended fiber	—	164,989 fibers/s
Start and stop a queue worker	—	114,077 workers/s
Start and stop an actor shell	—	106,530 actors/s
Start and stop two actor shells	—	60,676 families/s
Update an owner-only mutable snapshot	—	316,856,781 updates/s
Update a synchronized snapshot	—	1,527,774 updates/s
Create, resolve, and await a terminal latch	—	1,452,262 latches/s

Memory profile	Effect Machine	XState 5	XState 6 alpha	Effect runtime primitives
Idle machine	2.0 KiB	3.8 KiB	6.1 KiB	—
Raw generic managed process	12.3 KiB	—	—	—
Raw compiled process	2.7 KiB	—	—	—
Two independent idle machines	3.5 KiB	7.3 KiB	11.8 KiB	—
Idle parent with one child	5.8 KiB	5.5 KiB	8.8 KiB	—
Parent with observed child registry	10.0 KiB	—	—	—
Parent with observed invoked child snapshots	5.9 KiB	—	—	—
Suspended Effect fiber	—	—	—	0.7 KiB
Effect queue with waiting fiber	—	—	—	2.8 KiB
Effect mailbox actor shell	—	—	—	3.2 KiB
Two Effect actor shells	—	—	—	6.9 KiB

Effect Machine change from base

Metric	Base	Base variability	PR	PR variability	Difference
Plan counter transitions	116,587 transitions/s	3.0% MAD	119,077 transitions/s	1.0% MAD	+2.1%
Drain burst with terminal fence	234,487 increments/s	1.0% MAD	231,993 increments/s	2.8% MAD	-1.1%
Drain burst with a change observer	154,405 increments/s	1.3% MAD	152,323 increments/s	2.3% MAD	-1.3%
Lookup and send to one child	200,769 increments/s	0.6% MAD	199,989 increments/s	1.3% MAD	-0.4%
Start and stop a machine	26,040 machines/s	1.1% MAD	26,532 machines/s	1.6% MAD	+1.9%
Start and stop a parent with one child	9,291 families/s	3.3% MAD	9,351 families/s	2.8% MAD	+0.6%
Drain burst through a compound state	224,336 events/s	5.5% MAD	291,019 events/s	0.4% MAD	+29.7%
Drain burst through two parallel regions	216,175 events/s	0.6% MAD	273,549 events/s	0.1% MAD	+26.5%
Idle machine heap per unit	2.0 KiB	0.0% MAD	2.0 KiB	0.0% MAD	+0.0%
Raw generic managed process heap per unit	12.3 KiB	0.0% MAD	12.3 KiB	0.0% MAD	-0.0%
Raw compiled process heap per unit	2.7 KiB	0.0% MAD	2.7 KiB	0.1% MAD	+0.1%
Two independent idle machines heap per unit	3.5 KiB	0.0% MAD	3.5 KiB	0.0% MAD	+0.0%
Idle parent with one child heap per unit	5.8 KiB	0.2% MAD	5.8 KiB	0.0% MAD	-0.4%
Parent with observed child registry heap per unit	10.0 KiB	0.0% MAD	10.0 KiB	0.0% MAD	+0.0%
Parent with observed invoked child snapshots heap per unit	5.9 KiB	0.0% MAD	5.9 KiB	0.0% MAD	+0.0%

Effect runtime reference change from base

Metric	Base	Base variability	PR	PR variability	Difference
Start and stop a raw compiled process	34,419 processes/s	1.3% MAD	34,716 processes/s	0.3% MAD	+0.9%
Start and interrupt a suspended fiber	166,085 fibers/s	1.2% MAD	164,989 fibers/s	1.0% MAD	-0.7%
Start and stop a queue worker	116,198 workers/s	1.0% MAD	114,077 workers/s	1.6% MAD	-1.8%
Start and stop an actor shell	107,204 actors/s	0.9% MAD	106,530 actors/s	1.1% MAD	-0.6%
Start and stop two actor shells	65,967 families/s	0.9% MAD	60,676 families/s	4.6% MAD	-8.0%
Update an owner-only mutable snapshot	317,863,954 updates/s	0.0% MAD	316,856,781 updates/s	0.0% MAD	-0.3%
Update a synchronized snapshot	1,520,674 updates/s	2.1% MAD	1,527,774 updates/s	0.7% MAD	+0.5%
Create, resolve, and await a terminal latch	1,463,289 latches/s	0.4% MAD	1,452,262 latches/s	0.4% MAD	-0.8%

Versions and interpretation

• Effect Machine: 0.3.0
• XState 5: 5.32.5
• XState 6 alpha: 6.0.0-alpha.27
• Effect runtime primitives: 4.0.0-beta.105

Higher throughput is better; lower heap is better. Variability is the median absolute deviation across independent processes, relative to their median. Runtime measurements on shared GitHub-hosted hardware remain informational, so small differences should be confirmed across multiple workflow runs.