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 633.45 MiB.

Total analysed size: 231.52 MiB

Methods: 64.19 MiB for 436465 methods.

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

String literals size: 8.50 MiB

Classes: 94.43 MiB for 31947 classess.

Instance Side: 38.20 MiB

Without method dictionaries: 13.49 MiB

By componets: 37.80 MiB

Method dictionaries: 24.71 MiB

Basic Size in Memory: 3.24 MiB

Other: 9.85 MiB

Subclasses: 289.77 KiB

Protocols: 6.24 MiB

Layout: 748.45 KiB

Shared pools: 2.60 MiB

Class side: 56.22 MiB (metaclasses)

Without method dictionaries: 32.60 MiB

By componets: 28.96 MiB

Method dictionaries: 23.63 MiB

Basic Size in Memory: 1.95 MiB

Other: 3.39 MiB

Protocols: 2.66 MiB

Layout: 748.76 KiB

By data:

Basic Size in Memory: 5.18 MiB

Method dictionaries: 48.34 MiB

Subclasses: 289.77 KiB

Protocols: 8.90 MiB

Shared pools: 2.60 MiB

Layout: 1.46 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: 6.65 MiB for 215723 symbols

Pragmas Cache: 5.12 MiB

GT Completion Cache: 57.20 MiB

Packages: 1.86 MiB

Navigation Environment: 2.08 MiB

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

Traits overhead: 12.84 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:

79186 instances

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

32.37 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' :

436626 instances

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

37.04 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

126079 instances

7.35 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