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 626.45 MiB.

Total analysed size: 225.16 MiB

Methods: 61.91 MiB for 426590 methods.

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

String literals size: 7.62 MiB

Classes: 92.10 MiB for 31198 classess.

Instance Side: 37.20 MiB

Without method dictionaries: 13.16 MiB

By componets: 36.80 MiB

Method dictionaries: 24.04 MiB

Basic Size in Memory: 3.16 MiB

Other: 9.60 MiB

Subclasses: 283.17 KiB

Protocols: 6.09 MiB

Layout: 730.89 KiB

Shared pools: 2.51 MiB

Class side: 54.90 MiB (metaclasses)

Without method dictionaries: 31.90 MiB

By componets: 28.24 MiB

Method dictionaries: 23.01 MiB

Basic Size in Memory: 1.90 MiB

Other: 3.33 MiB

Protocols: 2.62 MiB

Layout: 731.20 KiB

By data:

Basic Size in Memory: 5.06 MiB

Method dictionaries: 47.05 MiB

Subclasses: 283.17 KiB

Protocols: 8.71 MiB

Shared pools: 2.51 MiB

Layout: 1.43 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: 6.47 MiB for 210870 symbols

Pragmas Cache: 5.03 MiB

GT Completion Cache: 55.77 MiB

Packages: 1.83 MiB

Navigation Environment: 2.05 MiB

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

Traits overhead: 12.60 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:

77414 instances

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

31.55 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' :

426751 instances

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

36.14 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

122887 instances

7.16 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