RFR: 8339290: Optimize ClassFile Utf8EntryImpl#writeTo [v17]

[Shaojin Wen]

On Tue, 3 Sep 2024 16:27:58 GMT, Shaojin Wen <swen at 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 one additional commit since the last revision:
> 
>   optimize for utf16

5d2e88fd9d808ec636b3dc7eb3e642ee864b1655 This version has resolved the startup performance regression in non-LATIN1 scenarios, and works well in scenarios where COMPACT_STRINGS=false or UTF16 strings with mostly ASCII characters in the prefix.

## 1. This intermediate mode

### 1.1 Script

git remote add wenshao git at github.com:wenshao/jdk.git
git fetch wenshao

# baseline
git checkout 5d2e88fd9d808ec636b3dc7eb3e642ee864b1655
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo" MICRO="VM_OPTIONS=-Xint"

# current
git checkout 059bece2b1b4aac644ee5e3c3c69246bd7cf50b6
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo" MICRO="VM_OPTIONS=-Xint"


### 1.2 MacBook M1 Pro Performance Numbers


-# baseline
-Benchmark                   (charType)  Mode  Cnt        Score       Error  Units
-Utf8EntryWriteTo.writeTo         ascii  avgt    9  1509448.291 ?  2654.329  ns/op
-Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9  1583379.661 ?  4149.880  ns/op
-Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  2197701.771 ? 13988.343  ns/op
-Utf8EntryWriteTo.writeTo         emoji  avgt    9  2271586.139 ?  5295.697  ns/op

+# current
+Benchmark                   (charType)  Mode  Cnt        Score      Error  Units
+Utf8EntryWriteTo.writeTo         ascii  avgt    9   178505.438 ? 4274.523  ns/op
+Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9   211906.736 ? 1033.539  ns/op
+Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  1303843.386 ? 3763.852  ns/op
+Utf8EntryWriteTo.writeTo         emoji  avgt    9  1360258.109 ? 4651.772  ns/op


|   | charType | baseline  | current | delta |
| --- | --- | --- | --- | --- |
| Utf8EntryWriteTo.writeTo | ascii | 1509448.291 | 178505.438 | 745.60% |
| Utf8EntryWriteTo.writeTo | utf8_2_bytes | 1583379.661 | 211906.736 | 647.21% |
| Utf8EntryWriteTo.writeTo | utf8_3_bytes | 2197701.771 | 1303843.386 | 68.56% |
| Utf8EntryWriteTo.writeTo | emoji | 2271586.139 | 1360258.109 | 67.00% |



## 2. TieredStopAtLevel=1

### 2.1 Script

git remote add wenshao git at github.com:wenshao/jdk.git
git fetch wenshao

# baseline
git checkout 5d2e88fd9d808ec636b3dc7eb3e642ee864b1655
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo" MICRO="VM_OPTIONS=-Xint -XX:TieredStopAtLevel=1"

# current
git checkout 059bece2b1b4aac644ee5e3c3c69246bd7cf50b6
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo" MICRO="VM_OPTIONS=-Xint -XX:TieredStopAtLevel=1"



### 2.2 MacBook M1 Pro Performance Numbers


-# baseline
-Benchmark                   (charType)  Mode  Cnt      Score     Error  Units
-Utf8EntryWriteTo.writeTo         ascii  avgt    9  23496.089 ? 200.645  ns/op
-Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9  24994.492 ? 221.328  ns/op
-Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  24572.165 ?  58.997  ns/op
-Utf8EntryWriteTo.writeTo         emoji  avgt    9  25345.417 ?  65.883  ns/op

+# current
+Benchmark                   (charType)  Mode  Cnt      Score    Error  Units
+Utf8EntryWriteTo.writeTo         ascii  avgt    9   7949.429 ? 33.514  ns/op
+Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9   8661.021 ? 55.333  ns/op
+Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  18511.109 ? 18.346  ns/op
+Utf8EntryWriteTo.writeTo         emoji  avgt    9  19239.642 ? 78.234  ns/op


|   | charType | baseline  | current | delta |
| --- | --- | --- | --- | --- |
| Utf8EntryWriteTo.writeTo | ascii | 23496.089 | 7949.429 | 195.57% |
| Utf8EntryWriteTo.writeTo | utf8_2_bytes | 24994.492 | 8661.021 | 188.59% |
| Utf8EntryWriteTo.writeTo | utf8_3_bytes | 24572.165 | 18511.109 | 32.74% |
| Utf8EntryWriteTo.writeTo | emoji | 25345.417 | 19239.642 | 31.74% |




## 3. Non-JVM Options

### 3.1 Script

git remote add wenshao git at github.com:wenshao/jdk.git
git fetch wenshao

# baseline
git checkout 5d2e88fd9d808ec636b3dc7eb3e642ee864b1655
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo"

# current
git checkout 059bece2b1b4aac644ee5e3c3c69246bd7cf50b6
make test TEST="micro:java.lang.classfile.Utf8EntryWriteTo"


### 3.2 MacBook M1 Pro Performance Numbers


-# baseline
-Benchmark                   (charType)  Mode  Cnt      Score     Error  Units
-Utf8EntryWriteTo.writeTo         ascii  avgt    9  15178.781 ?  38.239  ns/op
-Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9  16335.573 ? 288.536  ns/op
-Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  16008.245 ?  47.895  ns/op
-Utf8EntryWriteTo.writeTo         emoji  avgt    9  16619.964 ? 161.419  ns/op

+# current
+Benchmark                   (charType)  Mode  Cnt     Score     Error  Units
+Utf8EntryWriteTo.writeTo         ascii  avgt    9  4200.584 ?  82.228  ns/op
+Utf8EntryWriteTo.writeTo  utf8_2_bytes  avgt    9  5019.010 ?  20.490  ns/op
+Utf8EntryWriteTo.writeTo  utf8_3_bytes  avgt    9  7811.282 ?  27.938  ns/op
+Utf8EntryWriteTo.writeTo         emoji  avgt    9  8106.677 ? 134.932  ns/op


|   | charType | baseline  | current | delta |
| --- | --- | --- | --- | --- |
| Utf8EntryWriteTo.writeTo | ascii | 15178.781 | 4200.584 | 261.35% |
| Utf8EntryWriteTo.writeTo | utf8_2_bytes | 16335.573 | 5019.010 | 225.47% |
| Utf8EntryWriteTo.writeTo | utf8_3_bytes | 16008.245 | 7811.282 | 104.94% |
| Utf8EntryWriteTo.writeTo | emoji | 16619.964 | 8106.677 | 105.02% |

-------------

PR Comment: https://git.openjdk.org/jdk/pull/20772#issuecomment-2327597330