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 612.66 MiB.

Total analysed size: 228.27 MiB

Methods: 62.83 MiB for 432200 methods.

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

String literals size: 7.70 MiB

Classes: 93.25 MiB for 31575 classess.

Instance Side: 37.75 MiB

Without method dictionaries: 13.33 MiB

By componets: 37.35 MiB

Method dictionaries: 24.42 MiB

Basic Size in Memory: 3.20 MiB

Other: 9.73 MiB

Subclasses: 286.49 KiB

Protocols: 6.17 MiB

Layout: 739.73 KiB

Shared pools: 2.56 MiB

Class side: 55.50 MiB (metaclasses)

Without method dictionaries: 32.20 MiB

By componets: 28.58 MiB

Method dictionaries: 23.30 MiB

Basic Size in Memory: 1.92 MiB

Other: 3.36 MiB

Protocols: 2.63 MiB

Layout: 740.04 KiB

By data:

Basic Size in Memory: 5.12 MiB

Method dictionaries: 47.71 MiB

Subclasses: 286.49 KiB

Protocols: 8.81 MiB

Shared pools: 2.56 MiB

Layout: 1.45 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: 6.57 MiB for 213603 symbols

Pragmas Cache: 5.07 MiB

GT Completion Cache: 56.64 MiB

Packages: 1.84 MiB

Navigation Environment: 2.06 MiB

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

Traits overhead: 12.69 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:

78282 instances

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

31.94 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' :

432361 instances

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

36.65 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

124750 instances

7.27 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