Optimize DafnySequence<Character> to String#819
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olivergillespie wants to merge 2 commits intosmithy-lang:main-1.xfrom
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Optimize DafnySequence<Character> to String#819olivergillespie wants to merge 2 commits intosmithy-lang:main-1.xfrom
olivergillespie wants to merge 2 commits intosmithy-lang:main-1.xfrom
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(Re-cutting #819 on [olivergillespie](https://github.com/olivergillespie)'s behalf) Optimize performance of `ToNative$Simple.String`. I saw in an allocation profile of my application that this code is creating a lot of garbage, principally from calling `Character.toString` on every element, which creates a whole `String` object and backing `byte[]`. The `Stream` is wasteful too. Move to a `StringBuilder` and for loop. A very rough benchmark shows about 80% reduction in allocations and total time taken. Small string (4 chars): | | Time | Allocation | |---------|------|-------| | Baseline | 159 ns/op | 608 bytes/op | | Optimized | 37 ns/op | 96 bytes/op | Larger string (88 chars): | | Time | Allocation | |---------|------|-------| | Baseline | 2079 ns/op | 5360 bytes/op | | Optimized | 419 ns/op | 816 bytes/op | By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice. --------- Co-authored-by: Oli Gillespie <ogillesp@amazon.com>
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Merged in #820, thanks! |
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Optimize performance of
ToNative$Simple.String. I saw in an allocation profile of my application that this code is creating a lot of garbage, principally from callingCharacter.toStringon every element, which creates a wholeStringobject and backingbyte[]. TheStreamis wasteful too.Move to a
StringBuilderand for loop. A very rough benchmark shows about 80% reduction in allocations and total time taken.Small string (4 chars):
Larger string (88 chars):
By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.