Compile hierarchical machine execution

[SandroMaglione]

Summary

• compile event dispatch and hierarchy metadata for eligible compound and parallel machines
• specialize value-only leaf updates, final-state checks, and single-transition microsteps while preserving the general planner fallback
• add repeatable compound and parallel runtime benchmarks for Effect Machine, XState 5, and XState 6
• add differential coverage for parallel transitions, raised events, lazy context reads, completion, and managed runtime publication

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
• Reviewed the automated type-performance report, when the public TypeScript API or inference changed
• Reviewed the automated runtime-performance report, when runtime behavior changed

Local runtime comparison (Apple M1, Node v24.16.0; 5 base and 3 final-candidate processes) measured +88.9% compound-state throughput and +112.6% parallel-state throughput, with existing throughput and memory metrics unchanged within process variability.

[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	0.24s
machine.handle (depth 8)	0.52s	0.51s
machine.handle (depth 12)	0.56s	0.55s
machine.handle (depth 16)	0.60s	0.59s
machine.handle (depth 24)	0.68s	0.69s
machine.handle (wide depth 16)	0.73s	0.77s
machine.handle (parallel/history/choice)	0.61s	0.62s
machine.handle (4 successive calls)	0.58s	0.61s
machine exact input/output/error/services	0.49s	0.49s
execution adapter readiness	0.58s	0.57s

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 INTEL(R) XEON(R) PLATINUM 8573C with Node v24.18.0.

Pull request baseline

Scenario	Effect Machine	XState 5	XState 6 alpha
Plan counter transitions	131,209 transitions/s	143,981 transitions/s	111,972 transitions/s
Drain burst with terminal fence	266,919 increments/s	421,501 increments/s	106,382 increments/s
Drain burst with a change observer	181,759 increments/s	417,925 increments/s	106,290 increments/s
Lookup and send to one child	239,494 increments/s	418,892 increments/s	102,141 increments/s
Start and stop a machine	41,887 machines/s	201,694 machines/s	80,064 machines/s
Start and stop a parent with one child	16,564 families/s	77,997 families/s	33,049 families/s
Drain burst through a compound state	253,444 events/s	369,263 events/s	106,513 events/s
Drain burst through two parallel regions	239,412 events/s	287,376 events/s	92,491 events/s

Effect runtime reference points

Scenario	Effect Machine	Effect runtime primitives
Start and stop a raw compiled process	45,161 processes/s	—
Start and interrupt a suspended fiber	—	191,314 fibers/s
Start and stop a queue worker	—	136,388 workers/s
Start and stop an actor shell	—	127,049 actors/s
Start and stop two actor shells	—	78,296 families/s
Update an owner-only mutable snapshot	—	300,210,147 updates/s
Update a synchronized snapshot	—	1,759,919 updates/s
Create, resolve, and await a terminal latch	—	1,659,335 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	132,243 transitions/s	1.0% MAD	131,209 transitions/s	0.1% MAD	-0.8%
Drain burst with terminal fence	269,459 increments/s	0.7% MAD	266,919 increments/s	1.3% MAD	-0.9%
Drain burst with a change observer	179,879 increments/s	1.1% MAD	181,759 increments/s	0.8% MAD	+1.0%
Lookup and send to one child	240,082 increments/s	0.5% MAD	239,494 increments/s	0.2% MAD	-0.2%
Start and stop a machine	41,776 machines/s	0.2% MAD	41,887 machines/s	0.4% MAD	+0.3%
Start and stop a parent with one child	16,543 families/s	0.1% MAD	16,564 families/s	0.6% MAD	+0.1%
Drain burst through a compound state	133,007 events/s	0.8% MAD	253,444 events/s	0.6% MAD	+90.5%
Drain burst through two parallel regions	119,945 events/s	0.5% MAD	239,412 events/s	1.3% MAD	+99.6%
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	0.1% MAD	2.7 KiB	0.1% MAD	+0.0%
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	0.1% MAD	5.8 KiB	0.0% MAD	+0.5%
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	0.1% MAD	5.9 KiB	0.0% MAD	-0.1%

Effect runtime reference change from base

Metric	Base	Base variability	PR	PR variability	Difference
Start and stop a raw compiled process	45,556 processes/s	0.3% MAD	45,161 processes/s	0.2% MAD	-0.9%
Start and interrupt a suspended fiber	192,790 fibers/s	0.1% MAD	191,314 fibers/s	1.2% MAD	-0.8%
Start and stop a queue worker	139,140 workers/s	2.0% MAD	136,388 workers/s	1.4% MAD	-2.0%
Start and stop an actor shell	128,123 actors/s	0.8% MAD	127,049 actors/s	1.3% MAD	-0.8%
Start and stop two actor shells	79,650 families/s	0.7% MAD	78,296 families/s	1.3% MAD	-1.7%
Update an owner-only mutable snapshot	302,023,558 updates/s	0.0% MAD	300,210,147 updates/s	0.7% MAD	-0.6%
Update a synchronized snapshot	1,727,993 updates/s	2.8% MAD	1,759,919 updates/s	0.8% MAD	+1.8%
Create, resolve, and await a terminal latch	1,673,495 latches/s	1.0% MAD	1,659,335 latches/s	0.3% 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.