Analysing the size of code-related entities

This page provides an analysis for the size of the image, with a focus on the size of code entities, like methods and classes.

For performance reasons the vaues of these metrics are caches in GtMemoryMetrics Object << #GtMemoryMetrics slots: { #cache }; package: 'GToolkit-Releaser' . They can be reset using the snippet below.

GtMemoryMetrics reset
  

Current image size is 621.07 MiB.

Total analysed size: 222.67 MiB

Methods: 61.50 MiB for 423339 methods.

The size of methods includes all bytecodes, additional state and literals. Literals include strings and literal arrays, but excludes symbols.

String literals size: 7.59 MiB

Classes: 90.61 MiB for 30911 classess.

Instance Side: 36.84 MiB

Without method dictionaries: 13.03 MiB

By componets: 36.45 MiB

Method dictionaries: 23.81 MiB

Basic Size in Memory: 3.14 MiB

Other: 9.50 MiB

Subclasses: 280.02 KiB

Protocols: 6.04 MiB

Layout: 724.16 KiB

Shared pools: 2.48 MiB

Class side: 53.76 MiB (metaclasses)

Without method dictionaries: 31.16 MiB

By componets: 27.79 MiB

Method dictionaries: 22.60 MiB

Basic Size in Memory: 1.88 MiB

Other: 3.31 MiB

Protocols: 2.60 MiB

Layout: 724.48 KiB

By data:

Basic Size in Memory: 5.02 MiB

Method dictionaries: 46.41 MiB

Subclasses: 280.02 KiB

Protocols: 8.64 MiB

Shared pools: 2.48 MiB

Layout: 1.41 MiB

The size of classes includes the size of the class object and various method dictionaries, but excludes the actual methods in those dictionaries

Symbols: 6.41 MiB for 209196 symbols

Pragmas Cache: 4.99 MiB

GT Completion Cache: 55.32 MiB

Packages: 1.81 MiB

Navigation Environment: 2.03 MiB

When using traits, metaclasses use two extra arrays. This can introduce a memory overhead when traits have many users.

Traits overhead: 12.43 MiB

This measures the size of several types of instances, to double check that the previous calculations did not miss something.

MethodDictionary Dictionary << #MethodDictionary layout: VariableLayout; slots: {}; tag: 'Methods'; package: 'Kernel-CodeModel' sanity check:

76508 instances

72.37 MiB using HashedCollection>>#gtSpecificSizeInMemory gtSpecificSizeInMemory ^ self sizeInMemory + array sizeInMemory

30.93 MiB using #selector instancesSizeInMemory "Answers the number of bytes consumed by all its instances including their object header. Note: we do not use #allInstances as allInstancesDo: has a fallback for low memory" | bytes | bytes := 0. self allInstancesDo: [:each | bytes := bytes + each sizeInMemory ]. ^ bytes

CompiledMethod CompiledCode << #CompiledMethod layout: CompiledMethodLayout; slots: {}; tag: 'Methods'; package: 'Kernel-CodeModel' :

423501 instances

61.53 MiB using CompiledMethod>>#gtSpecificSizeInMemory gtSpecificSizeInMemory ^ super gtSpecificSizeInMemory + (self penultimateLiteral isMethodProperties ifTrue: [ self penultimateLiteral sizeInMemory ] ifFalse: [ 0 ])

35.86 MiB using #selector instancesSizeInMemory "Answers the number of bytes consumed by all its instances including their object header. Note: we do not use #allInstances as allInstancesDo: has a fallback for low memory" | bytes | bytes := 0. self allInstancesDo: [:each | bytes := bytes + each sizeInMemory ]. ^ bytes

CompiledBlock CompiledCode << #CompiledBlock layout: CompiledMethodLayout; slots: {}; tag: 'Methods'; package: 'Kernel-CodeModel' instances

122227 instances

7.15 MiB using #selector instancesSizeInMemory "Answers the number of bytes consumed by all its instances including their object header. Note: we do not use #allInstances as allInstancesDo: has a fallback for low memory" | bytes | bytes := 0. self allInstancesDo: [:each | bytes := bytes + each sizeInMemory ]. ^ bytes

ClassOrganization Object << #ClassOrganization slots: {}; package: 'GToolkit-Pharo11Stubs' :

0 instances

0 B using ClassOrganization>>#gtSpecificSizeInMemory gtSpecificSizeInMemory ^ self sizeInMemory + protocolOrganizer gtSpecificSizeInMemory