Shrink Trienodes

[benaadams]

Changes

• TrieNode _storageRoot only needs to exist on Leaf saving 8 bytes
• LastSeen can be combined with the other flags saving 8 bytes
• _data can be converted to fields/inline array saving 24 bytes; and removing one object per TrieNode (are a lot of object in trie and GC time is a function of object count)

Before

Type layout for 'TrieNode'
Size: 48 bytes. Paddings: 1 bytes (%2 of empty space)
|==============================================================|
| Object Header (8 bytes)                                      |
|--------------------------------------------------------------|
| Method Table Ptr (8 bytes)                                   |
|==============================================================|
|   0-7: TrieNode _storageRoot (8 bytes)                       |
|--------------------------------------------------------------|
|  8-15: RlpFactory _rlp (8 bytes)                             |
|--------------------------------------------------------------|
| 16-23: Object[] _data (8 bytes)                              |
|--------------------------------------------------------------|
| 24-31: Hash256 <Keccak>k__BackingField (8 bytes)             |
|--------------------------------------------------------------|
| 32-39: Int64 <LastSeen>k__BackingField (8 bytes)             |
|--------------------------------------------------------------|
| 40-43: Int32 _isDirty (4 bytes)                              |
|--------------------------------------------------------------|
|    44: Boolean <IsBoundaryProofNode>k__BackingField (1 byte) |
|--------------------------------------------------------------|
|    45: Boolean <IsPersisted>k__BackingField (1 byte)         |
|--------------------------------------------------------------|
|    46: NodeType <NodeType>k__BackingField (1 byte)           |
| |==============================|                             |
| |     0: Byte value__ (1 byte) |                             |
| |==============================|                             |
|--------------------------------------------------------------|
|    47: padding (1 byte)                                      |
|==============================================================|

After

Type layout for 'TrieNode'
Size: 32 bytes. Paddings: 0 bytes (%0 of empty space)
|==================================================|
| Object Header (8 bytes)                          |
|--------------------------------------------------|
| Method Table Ptr (8 bytes)                       |
|==================================================|
|   0-7: RlpFactory _rlp (8 bytes)                 |
|--------------------------------------------------|
|  8-15: INodeData _nodeData (8 bytes)             |
|--------------------------------------------------|
| 16-23: Hash256 <Keccak>k__BackingField (8 bytes) |
|--------------------------------------------------|
| 24-31: Int64 _blockAndFlags (8 bytes)            |
|==================================================|


Type layout for 'BranchData'
Size: 128 bytes. Paddings: 120 bytes (%93 of empty space)
|==========================================|
| Object Header (8 bytes)                  |
|------------------------------------------|
| Method Table Ptr (8 bytes)               |
|==========================================|
| 0-127: BranchArray _branches (128 bytes) |
| |===================================|    |
| |   0-7: Object _element0 (8 bytes) |    |
| |-----------------------------------|    |
| | 8-127: padding (120 bytes)        |    |
| |===================================|    |
|==========================================|


Type layout for 'ExtensionData'
Size: 16 bytes. Paddings: 0 bytes (%0 of empty space)
|================================|
| Object Header (8 bytes)        |
|--------------------------------|
| Method Table Ptr (8 bytes)     |
|================================|
|   0-7: Byte[] _key (8 bytes)   |
|--------------------------------|
|  8-15: Object _value (8 bytes) |
|================================|


Type layout for 'LeafData'
Size: 32 bytes. Paddings: 4 bytes (%12 of empty space)
|========================================================|
| Object Header (8 bytes)                                |
|--------------------------------------------------------|
| Method Table Ptr (8 bytes)                             |
|========================================================|
|   0-7: Byte[] <Key>k__BackingField (8 bytes)           |
|--------------------------------------------------------|
|  8-15: TrieNode <StorageRoot>k__BackingField (8 bytes) |
|--------------------------------------------------------|
| 16-31: CappedArray`1 _value (16 bytes)                 |
| |================================|                     |
| |   0-7: Byte[] _array (8 bytes) |                     |
| |--------------------------------|                     |
| |  8-11: Int32 _length (4 bytes) |                     |
| |--------------------------------|                     |
| | 12-15: padding (4 bytes)       |                     |
| |================================|                     |
|========================================================|

Types of changes

What types of changes does your code introduce?

• Optimization
• Refactoring

[LukaszRozmej]

Should we change Keccak from Hash256? to ValueHash256??

[LukaszRozmej]

Inline array?

[benaadams]

Is a bunch of follow up work that can be done; but probably good as now

[benaadams]

Should we change Keccak from Hash256? to ValueHash256??

Problematic since the entries in the level above are TrieNode or Hash256; so either the inline array in branches goes from 128 bytes to 512 bytes, or we box the ValueHash256 so it can go in an object reference, but then might as well have just kept it as a Hash256?

[asdacap]

LGTM