On Tue, 3 Sep 2024 00:38:40 GMT, Shaojin Wen <s...@openjdk.org> wrote:

>> Use fast path for ascii characters 1 to 127 to improve the performance of 
>> writing Utf8Entry to BufferWriter.
>
> Shaojin Wen has updated the pull request incrementally with two additional 
> commits since the last revision:
> 
>  - code style
>  - remove unsafe

Past experience with using intrinsics to replace similar counted loops shows 
that we can expect a 4-6x speed-up at scale, but only a very minor improvement 
for strings < 256 chars (branch, call and setup overheads eat up gains). See 
UTF-8 numbers here: 
https://cl4es.github.io/2021/02/23/Faster-Charset-Decoding.html - where we 
replace an ASCII-checking loop with an intrinsic: 
https://github.com/openjdk/jdk/pull/2574/files#diff-e5a7e70ec8192692004da7744aa38f222c64697194fbdc5278a1945234bb57dcR231
 

Since most strings in classfiles can be expected to be relatively short then a 
vectorized intrinsic might not be much of a win.

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PR Comment: https://git.openjdk.org/jdk/pull/20772#issuecomment-2325931262

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