On Fri, 29 Nov 2024 07:55:25 GMT, Per Minborg <pminb...@openjdk.org> wrote:
> This PR proposes to rewrite the `StringSupport::chunkedStrlen*` methods and > move them to the class `SegmentBulkOperations` where other bulk operations > reside. > > This PR fixes a bug in the `short_strlen` variant for offsets that were odd > (`offset % 2 != 0`). > > This PR also improves performance on modern hardware, as there is no need for > pre-looping alignment. Removing this improves performance by about 30% for > larger strings. > > Passes the `jdk_foreign` test suit. > > Base: > > > Benchmark (size) Mode Cnt Score Error > Units > InternalStrLen.changedElementQuad 1 avgt 30 2.057 ? 0.012 > ns/op > InternalStrLen.changedElementQuad 4 avgt 30 3.776 ? 0.031 > ns/op > InternalStrLen.changedElementQuad 16 avgt 30 6.690 ? 0.060 > ns/op > InternalStrLen.changedElementQuad 251 avgt 30 48.581 ? 0.764 > ns/op > InternalStrLen.changedElementQuad 1024 avgt 30 196.188 ? 3.484 > ns/op > InternalStrLen.chunkedDouble 1 avgt 30 1.903 ? 0.013 > ns/op > InternalStrLen.chunkedDouble 4 avgt 30 3.446 ? 0.025 > ns/op > InternalStrLen.chunkedDouble 16 avgt 30 5.759 ? 0.062 > ns/op > InternalStrLen.chunkedDouble 251 avgt 30 26.892 ? 0.141 > ns/op > InternalStrLen.chunkedDouble 1024 avgt 30 72.940 ? 1.562 > ns/op > InternalStrLen.chunkedSingle 1 avgt 30 1.897 ? 0.015 > ns/op > InternalStrLen.chunkedSingle 4 avgt 30 5.357 ? 0.560 > ns/op > InternalStrLen.chunkedSingle 16 avgt 30 3.821 ? 0.052 > ns/op > InternalStrLen.chunkedSingle 251 avgt 30 19.482 ? 0.190 > ns/op > InternalStrLen.chunkedSingle 1024 avgt 30 38.938 ? 0.411 > ns/op > InternalStrLen.chunkedSingleMisaligned 1 avgt 30 2.230 ? 0.147 > ns/op > InternalStrLen.chunkedSingleMisaligned 4 avgt 30 5.424 ? 0.688 > ns/op > InternalStrLen.chunkedSingleMisaligned 16 avgt 30 9.573 ? 0.063 > ns/op > InternalStrLen.chunkedSingleMisaligned 251 avgt 30 22.242 ? 0.182 > ns/op > InternalStrLen.chunkedSingleMisaligned 1024 avgt 30 45.442 ? 0.252 > ns/op > InternalStrLen.elementByteMisaligned 1 avgt 30 1.616 ? 0.041 > ns/op > InternalStrLen.elementByteMisaligned 4 avgt 30 2.982 ? 0.018 > ns/op > InternalStrLen.elementByteMisaligned 16 avgt 30 8.662 ? 0.085 > ns/op > InternalStrLen.elementByteMisaligned 251 avgt 30 ... src/java.base/share/classes/jdk/internal/foreign/SegmentBulkOperations.java line 400: > 398: */ > 399: @ForceInline > 400: public static int strlenByte(final AbstractMemorySegmentImpl segment, Can we put these back in `StringSupport`? It makes it hard to review the differences side-by-side. (We can maybe decide later whether to move). In general if we keep the `StringSupport` class it's a bit weird to have the `strlen` methods not be there -- but I agree there's a similarity between this and other bulk operations. src/java.base/share/classes/jdk/internal/foreign/SegmentBulkOperations.java line 504: > 502: > 503: > 504: /* // The gain of using `long` wide operations for `int` is lower > than for the two other Leftover? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/22451#discussion_r1863181620 PR Review Comment: https://git.openjdk.org/jdk/pull/22451#discussion_r1863176170
