Native memory allocators reference
Reference for native memory allocator settings
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You can control how native memory is allocated through using command line arguments, or using the settings in the Unity Editor (Edit > Project Settings > Memory Settings). For information on how to customize native memory allocators, refer to Customizing native memory allocators.
Project Settings > Memory Settings, showing a selection of Player memory settings
The following table contains information about each allocator setting, plus their command line arguments, and their default values:
Main Allocators
These allocators are the ones that Unity uses for most allocations.
Main Allocator
The primary allocator Unity uses for most allocations. It has the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| Main Thread Block Size | Block size of dedicated main thread allocator. This property is automatically disabled when you use mimalloc. | | |
| Shared Thread Block Size | Block size of shared thread allocator. This property is automatically disabled when you use mimalloc. | | |
| Mimalloc enabled | Uses mimalloc instead of the main thread and shared thread. | None | Enabled |
Gfx Allocator
The allocator Unity uses for CPU allocations related to the Gfx system. It has the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| Main Thread Block Size | Block size of the dedicated main thread Gfx allocator. | | |
| Shared Thread Block Size | Block size of the shared thread Gfx allocator. | | |
Other Allocators
Allocations used for type trees and the file cache. It has the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| File Cache Block Size | The file cache has its own allocator to avoid fragmentation. This is its block size. | | |
| Type Tree Block Size | The type trees have their own allocator to avoid fragmentation due to many small allocations. This is its block size. | | |
Shared Bucket Allocator
The bucket allocator shared between the main allocators. It has the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| Bucket Allocator Granularity | Step size for buckets in the shared allocator. | | |
| Bucket Allocator BucketCount | Number of bucket sizes. | | |
| Bucket Allocator Block Size | Size of memory blocks used for buckets. | | Editor: Player: |
| Bucket Allocator Block Count | Maximum number of blocks to be allocated. | | Editor: Player: |
Fast Per Thread Temporary Allocators
The Thread Local Storage (TLS) allocator that handles very short-lived allocations.
Allocator | Description | Command line argument | Default value (in bytes) |
|---|---|---|---|
| Main Thread Block Size | The initial size for the main thread stack. | | Editor: Player: |
| Job Worker Block Size | Size of each job worker in the Unity job system. | | |
| Background Job Worker Block Size | Size for each background worker. | | |
| Preload Block Size | The preload manager stack size. | | Editor: Player: |
| Audio Worker Block Size | Each audio worker thread's stack size. | | |
| Cloud Worker Block Size | Cloud worker threads stack size. | | |
| Gfx Thread Blocksize | The main render threads stack size. | | |
| GI Baking Blocksize | Each GI worker thread's stack size. | | |
| NavMesh Worker Block Size | Nav mesh worker threads stack size. | | |
Fast Thread Shared Temporary Allocators
Fast linear allocator for short lived allocations shared between threads.
Allocator | Description | Command line argument | Default value (in bytes) |
|---|---|---|---|
| Job Allocator Block Size | The round robin linear thread allocator Unity mainly uses for the job worker threads. | | |
| Background Job Allocator Block Size | The linear allocator for the background workers that allows longer lived allocations. | | |
| Job Allocator Block Size on low memory platforms | Platforms with less than 2 GB memory use this size for both the job workers and the background jobs. | | |
Profiler Allocators
Allocators that Unity uses exclusively for the Profiler so that they don't interfere with the application's allocation patterns. They have the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| Profiler Block Size | The block size for the main part of the Profiler. | | |
| Editor Profiler Block Size | Block size for the Editor part of the Profiler. This isn't present in players. | | |
Shared Profiler Bucket Allocator
Shared bucket allocator for the Profiler and Editor Profiler allocators. Not present on low memory platforms. It has the following settings:
Setting | Description | Command line argument | Default value |
|---|---|---|---|
| Bucket Allocator Granularity | Step size for buckets in the shared allocator. | | |
| Bucket Allocator BucketCount | Number of bucket sizes. For example, if the value is 4, the sizes are 16 bytes, 32 bytes, 48 bytes, and 64 bytes. | | |
| Bucket Allocator Block Size | Size of memory blocks used for buckets. | | Editor: Player: |
| Bucket Allocator Block Count | Maximum number of blocks to be allocated. | | Editor: Player: |