Integrated: 8269559: AArch64: Implement string_compare intrinsic in SVE

[TatWai Chong]

On Mon, 16 Aug 2021 20:59:55 GMT, TatWai Chong <duke at openjdk.java.net> wrote:

> This patch implements string_compare intrinsic in SVE.
> It supports all LL, LU, UL and UU comparisons.
> 
> As we haven't found an existing benchmark to measure performance impact,
> we created a benchmark derived from the test [1] for this evaluation.
> This benchmark is attached to this patch.
> 
> Besides, remove the unused temporary register `vtmp3` from the existing
> match rules for StrCmp.
> 
> The result below shows all varients can be benefited largely.
> Command: make exploded-test TEST="micro:StringCompareToDifferentLength"
> 
> Benchmark    (size)  Mode  Cnt   Score Speedup Units
> compareToLL      24  avgt   10      1.0x       ms/op
> compareToLL      36  avgt   10      1.0x       ms/op
> compareToLL      72  avgt   10      1.0x       ms/op
> compareToLL     128  avgt   10      1.4x       ms/op
> compareToLL     256  avgt   10      1.8x       ms/op
> compareToLL     512  avgt   10      2.7x       ms/op
> compareToLU      24  avgt   10      1.6x       ms/op
> compareToLU      36  avgt   10      1.8x       ms/op
> compareToLU      72  avgt   10      2.3x       ms/op
> compareToLU     128  avgt   10      3.8x       ms/op
> compareToLU     256  avgt   10      4.7x       ms/op
> compareToLU     512  avgt   10      6.3x       ms/op
> compareToUL      24  avgt   10      1.6x       ms/op
> compareToUL      36  avgt   10      1.7x       ms/op
> compareToUL      72  avgt   10      2.2x       ms/op
> compareToUL     128  avgt   10      3.3x       ms/op
> compareToUL     256  avgt   10      4.4x       ms/op
> compareToUL     512  avgt   10      6.1x       ms/op
> compareToUU      24  avgt   10      1.0x       ms/op
> compareToUU      36  avgt   10      1.0x       ms/op
> compareToUU      72  avgt   10      1.4x       ms/op
> compareToUU     128  avgt   10      2.2x       ms/op
> compareToUU     256  avgt   10      2.6x       ms/op
> compareToUU     512  avgt   10      3.7x       ms/op
> 
> [1] https://github.com/openjdk/jdk/blob/master/test/hotspot/jtreg/compiler/intrinsics/string/TestStringCompareToDifferentLength.java

This pull request has now been integrated.

Changeset: 8b1b6f9f
Author:    TatWai Chong <tatwai.chong at arm.com>
Committer: Nick Gasson <ngasson at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/8b1b6f9fb375bbc2de339ad8f526ca4d5f83dc70
Stats:     517 lines in 11 files changed: 421 ins; 1 del; 95 mod

8269559: AArch64: Implement string_compare intrinsic in SVE

Reviewed-by: ngasson, aph

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PR: https://git.openjdk.java.net/jdk/pull/5129