ByteBuffer: one fewer allocs to go to Data #1839
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Lukasa
requested changes
Apr 30, 2021
| @@ -25,37 +26,39 @@ func run(identifier: String) { | |||
| @inline(never) | |||
| func doWrites(buffer: inout ByteBuffer) { | |||
| /* these ones are zero allocations */ | |||
| // buffer.writeBytes(foundationData) // see SR-7542 | |||
| buffer.writeBytes([0x41]) | ||
| buffer.writeBytes("A".utf8) | ||
| buffer.writeString("A") | ||
| buffer.writeStaticString("A") | ||
| buffer.writeInteger(0x41, as: UInt8.self) | ||
|
|
||
| /* those down here should be one allocation each (on Linux) */ | ||
| buffer.writeBytes(dispatchData) // see https://bugs.swift.org/browse/SR-9597 |
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Similarly, is this gone on purpose?
weissi
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Lukasa
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Jun 1, 2021
|
We should resurrect this |
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Motivation: When getting a `Data` from a `ByteBuffer` we currently allocate twice (`__DataStorage`) and the closure for `Data.Deallocator`. Modifications: We can optimise that by making the closure capture exactly one `AnyObject` which is already a reference counted object. The compiler realises that (on Linux) and saves us an alloc. Thanks @Lukasa for the suggestion here: apple#1836 (comment) Result: Fewer allocs.
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Motivation:
When getting a
Datafrom aByteBufferwe currently allocate twice(
__DataStorage) and the closure forData.Deallocator.Modifications:
We can optimise that by making the closure capture exactly one
AnyObjectwhich is already a reference counted object. The compilerrealises that (on Linux) and saves us an alloc.
Thanks @Lukasa for the suggestion here: #1836 (comment)
Result:
Fewer allocs.