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Improving the Ephemerons algorithm #702

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Improving the Ephemerons algorithm #702

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1ab3110
Add class that test some edge cases of the ephemerons algorithm
jordanmontt Oct 9, 2023
c9eb905
Added more tests exposing when the algorithm fails
jordanmontt Oct 26, 2023
ba5d1c4
Code reformatting
jordanmontt Oct 26, 2023
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361 changes: 361 additions & 0 deletions smalltalksrc/VMMakerTests/VMSpurEphemeronsAlgorithmTest.class.st
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Class {
#name : #VMSpurEphemeronsAlgorithmTest,
#superclass : #VMSpurInitializedOldSpaceTest,
#instVars : [
'ephemeronObjectOopOne',
'ephemeronObjectOopTwo',
'nonEphemeronObjectOopOne',
'nonEphemeronObjectOopTwo'
],
#category : #'VMMakerTests-MemoryTests'
}

{ #category : #helper }
VMSpurEphemeronsAlgorithmTest >> addKeysToEphemerons [

memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.

memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopTwo
]

{ #category : #helper }
VMSpurEphemeronsAlgorithmTest >> keepEphemeronsInVMVariables [
"Force ephemerons to not be collected by putting them in special variables"

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo
]

{ #category : #helper }
VMSpurEphemeronsAlgorithmTest >> newEphemeronObjectOldSpace [
"In pharo Ephemerons have 3 slots"

^ self newOldSpaceObjectWithSlots: 3
format: memory ephemeronFormat
classIndex: (memory ensureBehaviorHash: ourEphemeronClass)
]

{ #category : #running }
VMSpurEphemeronsAlgorithmTest >> setUp [

super setUp.
memory initializeMournQueue.
self createEphemeronClass
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsOldObjectsOld [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 1.
nonEphemeronObjectOopTwo := self newOldSpaceObjectWithSlots: 0.
"Make object 1 reference object 2"
memory storePointer: 0 ofObject: nonEphemeronObjectOopOne withValue: nonEphemeronObjectOopTwo.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory fullGC.

"ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo."

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsOldObjectsOldInverse [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 0.
nonEphemeronObjectOopTwo := self newOldSpaceObjectWithSlots: 1.
"Make object 2 reference object 1"
memory storePointer: 0 ofObject: nonEphemeronObjectOopTwo withValue: nonEphemeronObjectOopOne.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory fullGC.

"ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo."

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsOldObjectsYoung [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newObjectWithSlots: 1.
nonEphemeronObjectOopTwo := self newZeroSizedObject.
"Make object 1 reference object 2"
memory storePointer: 0 ofObject: nonEphemeronObjectOopOne withValue: nonEphemeronObjectOopTwo.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge:1 "Tenured by age".
memory fullGC.

"ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo."

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsOldObjectsYoungInverse [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newZeroSizedObject.
nonEphemeronObjectOopTwo := self newObjectWithSlots: 1.
"Make object 2 reference object 1"
memory storePointer: 0 ofObject: nonEphemeronObjectOopTwo withValue: nonEphemeronObjectOopOne.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge:1 "Tenured by age".
memory fullGC.

"ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo."

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - ephemerons with same key' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsWithSameKeyNewSpace [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newZeroSizedObject.

"Both ephemerons share the same key"
memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.
memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopOne.

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo.

"Collect ephemerons"
memory doScavenge: 1.

self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner).
self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner)
]

{ #category : #'tests - ephemerons with same key' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsWithSameKeyNewSpaceFlush [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newZeroSizedObject.

"Both ephemerons share the same key"
memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.
memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopOne.

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo.

"Collect both non ephemeron objects"
memory flushNewSpace.

self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner).
self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner)
]

{ #category : #'tests - ephemerons with same key' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsWithSameKeyNewSpaceOldSpace [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 0.

"Both ephemerons share the same key"
memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.
memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopOne.

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo.

"Collect ephemerons"
memory fullGC.

self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner).
self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner)
]

{ #category : #'tests - ephemerons with same key' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsWithSameKeyOldSpace [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 0.

"Both ephemerons share the same key"
memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.
memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopOne.

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo.

"Collect ephemerons"
memory fullGC.

self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner).
self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner)
]

{ #category : #'tests - ephemerons with same key' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsWithSameKeyOldSpaceNewSpace [

ephemeronObjectOopOne := self newEphemeronObjectOldSpace.
ephemeronObjectOopTwo := self newEphemeronObjectOldSpace.
nonEphemeronObjectOopOne := self newZeroSizedObject.

"Both ephemerons share the same key"
memory storePointer: 0
ofObject: ephemeronObjectOopOne
withValue: nonEphemeronObjectOopOne.
memory storePointer: 0
ofObject: ephemeronObjectOopTwo
withValue: nonEphemeronObjectOopOne.

self keepObjectInVMVariable1: ephemeronObjectOopOne.
self keepObjectInVMVariable2: ephemeronObjectOopTwo.

"Collect ephemerons"
memory fullGC.

self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner).
self assert: ({ ephemeronObjectOopOne. ephemeronObjectOopTwo } includes: memory dequeueMourner)
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsYoungObjectsOld [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 1.
nonEphemeronObjectOopTwo := self newOldSpaceObjectWithSlots: 0.
"Make object 1 reference object 2"
memory storePointer: 0 ofObject: nonEphemeronObjectOopOne withValue: nonEphemeronObjectOopTwo.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge:1 "Tenured by age".
memory fullGC.

ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo.

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsYoungObjectsOldInverse [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newOldSpaceObjectWithSlots: 0.
nonEphemeronObjectOopTwo := self newOldSpaceObjectWithSlots: 1.
"Make object 2 reference object 1"
memory storePointer: 0 ofObject: nonEphemeronObjectOopTwo withValue: nonEphemeronObjectOopOne.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge:1 "Tenured by age".
memory fullGC.

ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo.

self assert: memory dequeueMourner equals: ephemeronObjectOopTwo.
self assert: memory dequeueMourner equals: ephemeronObjectOopOne
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsYoungObjectsYoung [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newObjectWithSlots: 1.
nonEphemeronObjectOopTwo := self newZeroSizedObject.
"Make object 1 reference object 2"
memory storePointer: 0 ofObject: nonEphemeronObjectOopOne withValue: nonEphemeronObjectOopTwo.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge: 1. "TenureByAge"

ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo.

self assert: memory dequeueMourner equals: ephemeronObjectOopOne.
self assert: memory dequeueMourner equals: ephemeronObjectOopTwo
]

{ #category : #'tests - finalization - algorithm' }
VMSpurEphemeronsAlgorithmTest >> testEphemeronsYoungObjectsYoungInverse [

ephemeronObjectOopOne := self newEphemeronObject.
ephemeronObjectOopTwo := self newEphemeronObject.
nonEphemeronObjectOopOne := self newZeroSizedObject.
nonEphemeronObjectOopTwo := self newObjectWithSlots: 1.
"Make object 2 reference object 1"
memory storePointer: 0 ofObject: nonEphemeronObjectOopTwo withValue: nonEphemeronObjectOopOne.

self addKeysToEphemerons.
self keepEphemeronsInVMVariables.

"Collect both non ephemeron objects"
memory doScavenge: 1. "TenureByAge"

ephemeronObjectOopOne := memory remapObj: ephemeronObjectOopOne.
ephemeronObjectOopTwo := memory remapObj: ephemeronObjectOopTwo.

self assert: memory dequeueMourner equals: ephemeronObjectOopOne.
self assert: memory dequeueMourner equals: ephemeronObjectOopTwo
]