On Thu, 22 May 2025 08:14:35 GMT, Per Minborg <pminb...@openjdk.org> wrote:
>> This PR builds on a concept John Rose told me about some time ago. Instead
>> of combining memory operations of various sizes, a single large and skewed
>> memory operation can be made to clean up the tail of remaining bytes.
>>
>> This has the effect of simplifying and shortening the code. The number of
>> branches to evaluate is reduced.
>
> Per Minborg has updated the pull request incrementally with one additional
> commit since the last revision:
>
> Correct typo in comment
src/java.base/share/classes/jdk/internal/foreign/SegmentBulkOperations.java
line 93:
> 91: case 2 -> {
> 92: SCOPED_MEMORY_ACCESS.putShortUnaligned(dst.sessionImpl(),
> dst.unsafeGetBase(), dst.unsafeGetOffset(), (short) longValue,
> !Architecture.isLittleEndian());
> 93: SCOPED_MEMORY_ACCESS.putShortUnaligned(dst.sessionImpl(),
> dst.unsafeGetBase(), dst.unsafeGetOffset() + len - Short.BYTES, (short)
> longValue, !Architecture.isLittleEndian());
So that I understand, since this configuration might pick up both length = 2
and length = 3, in 50% of cases there's a redundant store? This is also true
for length = 4, 5, 6, 7 -- but in this case the chance of redundant store is
reduced to 25%.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/25383#discussion_r2102016436
