On Sat, 1 Jul 2023 01:44:15 GMT, 温绍锦 <d...@openjdk.org> wrote:
> [PR 14578 ](https://github.com/openjdk/jdk/pull/14578) still has unresolved
> discussions, continue to make improvements.
>
> # Benchmark Result
>
>
> sh make/devkit/createJMHBundle.sh
> bash configure --with-jmh=build/jmh/jars
> make test TEST="micro:java.util.UUIDBench.toString"
>
>
> ## 1.
> [aliyun_ecs_c8i.xlarge](https://help.aliyun.com/document_detail/25378.html#c8i)
> * cpu : intel xeon sapphire rapids (x64)
>
> ``` diff
> -Benchmark (size) Mode Cnt Score Error Units (baseline)
> -UUIDBench.toString 20000 thrpt 15 62.019 ± 0.622 ops/us
>
> +Benchmark (size) Mode Cnt Score Error Units
> +UUIDBench.toString 20000 thrpt 15 82.998 ± 0.739 ops/us (+33.82%)
>
>
> ## 2.
> [aliyun_ecs_c8a.xlarge](https://help.aliyun.com/document_detail/25378.html#c8a)
> * cpu : amd epc genoa (x64)
>
> ``` diff
> -Benchmark (size) Mode Cnt Score Error Units (baseline)
> -UUIDBench.toString 20000 thrpt 15 88.668 ± 0.672 ops/us
>
> +Benchmark (size) Mode Cnt Score Error Units
> +UUIDBench.toString 20000 thrpt 15 89.229 ± 0.271 ops/us (+0.63%)
>
>
>
> ## 3.
> [aliyun_ecs_c8y.xlarge](https://help.aliyun.com/document_detail/25378.html#c8y)
> * cpu : aliyun yitian 710 (aarch64)
> ``` diff
> -Benchmark (size) Mode Cnt Score Error Units (baseline)
> -UUIDBench.toString 20000 thrpt 15 49.382 ± 2.160 ops/us
>
> +Benchmark (size) Mode Cnt Score Error Units
> +UUIDBench.toString 20000 thrpt 15 49.636 ± 1.974 ops/us (+0.51%)
>
>
> ## 4. MacBookPro M1 Pro
> ``` diff
> -Benchmark (size) Mode Cnt Score Error Units (baseline)
> -UUIDBench.toString 20000 thrpt 15 103.543 ± 0.963 ops/us
>
> +Benchmark (size) Mode Cnt Score Error Units
> +UUIDBench.toString 20000 thrpt 15 110.976 ± 0.685 ops/us (+7.17%)
>
>
> ## 5. Orange Pi 5 Plus
>
> ``` diff
> -Benchmark (size) Mode Cnt Score Error Units (baseline)
> -UUIDBench.toString 20000 thrpt 15 33.532 ± 0.396 ops/us
>
> +Benchmark (size) Mode Cnt Score Error Units (PR)
> +UUIDBench.toString 20000 thrpt 15 33.054 ± 0.190 ops/us (-4.42%)
src/java.base/share/classes/java/util/HexDigits.java line 108:
> 106: * Combine two hex shorts into one int based on big endian
> 107: */
> 108: static int packDigits(int b0, int b1) {
I recommend such a refactor:
/**
* Return a big-endian packed integer for the 4 ASCII bytes for an input
unsigned short value.
*/
static int packDigits16(int b) {
return (DIGITS[(b >> 8) & 0xff] << 16) | DIGITS[b & 0xff];
}
And all your usages can be `HexDigits.packDigits16(((int) msb) >> 16)` and
`HexDigits.packDigits16((int) msb)` without the `>> 24` and `>> 8`
src/java.base/share/classes/java/util/HexDigits.java line 115:
> 113: * Combine four hex shorts into one long based on big endian
> 114: */
> 115: static long packDigits(int b0, int b1, int b2, int b3) {
Same comment here:
/**
* Return a big-endian packed long for the 8 ASCII bytes for an input unsigned
int value.
*/
static long packDigits32(int b) {
return (((long) DIGITS[(b >> 24) & 0xff]) << 48)
| (((long) DIGITS[(b >> 16) & 0xff]) << 32)
| (DIGITS[(b >> 8) & 0xff] << 16)
| DIGITS[b & 0xff];
}
And use sites become:
// old
HexDigits.packDigits((int) (msb >> 56), (int) (msb >> 48), (int) (msb >> 40),
(int) (msb >> 32))
// new
HexDigits.packDigits32((int) (msb >> 32))
and `HexDigits.packDigits32((int) (lsb >> 16))`
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/14745#discussion_r1248389049
PR Review Comment: https://git.openjdk.org/jdk/pull/14745#discussion_r1248394179
