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0f54180b51
New typed data implementation that optimizes the common cases.
This uses the best possible representation for the fast case with a
representation like:
class _I32List implements Int32List {
final WasmIntArray<WasmI32> _data;
int operator [](int index) {
// range check
return _data.read(index);
}
void operator []=(int index, int value) {
// range check
_data.writeSigned(index, value);
}
...
}
This gives us the best possible runtime performance in the common cases
of:
- The list is used directly.
- The list is used via a view of the same Wasm element type (e.g. a
`Uint32List` view of a `Int32List`) and with aligned byte offset.
All other classes (`ByteBuffer`, `ByteData`, and view classes)
implemented to be able to support this representation.
Summary of classes:
- One list class per Dart typed data list, with the matching Wasm array
as the buffer (as shown in the example above): `_I8List`, `_U8List`,
`_U8ClampedList`, `_I16List`, `_U16List`, ...
- One list class per Dart typed data list, with mismatching Wasm array
as the buffer. These classes are used when a view is created from a
list, and the original list has a Wasm array with different element
type than the view needs. `_SlowI8List`, `_SlowU8List`, ...
These classes use `ByteData` interface to update the buffer.
- One list class for each of the classes listed above, for immutable
views. `_UnmodifiableI32List`, `_UnmodifiableSlowU64List`, ...
These classes inherit from their modifiable list classes and override
update methods using a mixin.
- One `ByteData` class for each Wasm array type: `_I8ByteData`,
`_I16ByteData`,
...
- One immutable `ByteData` view for each `ByteData` class.
- One `ByteBuffer` class for each Wasm array type: `_I8ByteBuffer`,
`_I16ByteBuffer`, ...
- A single `ByteBuffer` class for the immutable view of a byte buffer.
We don't need one immutable `ByteBuffer` view class per Wasm array
type as `ByteBuffer` API does not provide direct access to the buffer.
Other optimizations:
- `setRange` now uses `array.copy` when possible, which causes a huge
performance win in some benchmarks.
- The new implementation is pure Dart and needs no support or special
cases from the compiler other than the Wasm array type support and
intrinsics like `array.copy`. As a result this removes a bunch of
`entry-point` pragmas and significantly reduces code size in some
cases.
Other changes:
- Patch and implementation files for typed data and SIMD types are split
into separate files. `typed_data_patch.dart` and `simd_patch.dart` now
only contains patched factories. Implementation classes are moved to
`typed_data.dart` and `simd.dart` as libraries `dart:_typed_data` and
`dart:_simd`.
Benchmark results:
This CL significantly improves common cases. New implementation is only
slower than the current implementation when a view uses a Wasm array
type with incompatible element type (for example, `Uint32List` created
from a `Uint64List`).
These cases can still be improved by overriding the relevant `ByteData`
methods. For example, in the example of `Uint32List` view of a
`Uint64List`, by overriding `_I64ByteData.getUint32` to do a single read
then requested bytes don't cross element boundaries in the Wasm array.
These optimizations are left as future work.
Some sample benchmarks:
vector_math matrix_bench before:
Binary size: 133,104 bytes.
MatrixMultiply(RunTime): 201 us.
SIMDMatrixMultiply(RunTime): 3,608 us.
VectorTransform(RunTime): 94 us.
SIMDVectorTransform(RunTime): 833 us.
setViewMatrix(RunTime): 506 us.
aabb2Transform(RunTime): 987 us.
aabb2Rotate(RunTime): 721 us.
aabb3Transform(RunTime): 1,710 us.
aabb3Rotate(RunTime): 1,156 us.
Matrix3.determinant(RunTime): 171 us.
Matrix3.transform(Vector3)(RunTime): 8,550 us.
Matrix3.transform(Vector2)(RunTime): 3924 us.
Matrix3.transposeMultiply(RunTime): 201 us.
vector_math matrix_bench after:
Binary size: 135,198 bytes.
MatrixMultiply(RunTime): 42 us.
SIMDMatrixMultiply(RunTime): 2,068 us.
VectorTransform(RunTime): 12 us.
SIMDVectorTransform(RunTime): 272 us.
setViewMatrix(RunTime): 82 us.
aabb2Transform(RunTime): 167 us.
aabb2Rotate(RunTime): 147 us.
aabb3Transform(RunTime): 194 us.
aabb3Rotate(RunTime): 199 us.
Matrix3.determinant(RunTime): 70 us.
Matrix3.transform(Vector3)(RunTime): 726 us.
Matrix3.transform(Vector2)(RunTime): 504 us.
Matrix3.transposeMultiply(RunTime): 53 us.
FluidMotion before:
Binary size: 121,130 bytes.
FluidMotion(RunTime): 270,625 us.
FluidMotion after:
Binary size: 110,674 bytes.
FluidMotion(RunTime): 71,357 us.
With bound checks omitted (not in this CL), FluidMotion becomes
competitive with `dart2js -O4`:
FluidMotion dart2js -O4:
FluidMotion(RunTime): 47,813 us.
FluidMotion this CL + boud checks omitted:
FluidMotion(RunTime): 51,289 us.
Fixes #52710.
Tested: With existing tests.
Change-Id: I33bf5585c3be5d3919a99af857659cf7d9393df0
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/312907
Reviewed-by: Joshua Litt <joshualitt@google.com>
Commit-Queue: Ömer Ağacan <omersa@google.com>
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