RFR: 8259699: Reduce char[] copying in URLEncoder.encode(String, Charset) [v3]

[Claes Redestad]

On Thu, 14 Jan 2021 11:48:16 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> @cl4es SB brings pessimization both for time and memory, try `org.openjdk.bench.java.net.URLEncodeDecode`:
>> master
>>                                                  (count)  (maxLength)  (mySeed)  Mode  Cnt         Score       Error   Units
>> testEncodeUTF8                                      1024         1024         3  avgt   25         8.573 ?     0.023   ms/op
>> testEncodeUTF8:?gc.alloc.rate                       1024         1024         3  avgt   25      1202.896 ?     3.225  MB/sec
>> testEncodeUTF8:?gc.alloc.rate.norm                  1024         1024         3  avgt   25  11355727.904 ?   196.249    B/op
>> testEncodeUTF8:?gc.churn.G1_Eden_Space              1024         1024         3  avgt   25      1203.785 ?     6.240  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Eden_Space.norm         1024         1024         3  avgt   25  11364143.637 ? 52830.222    B/op
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space          1024         1024         3  avgt   25         0.008 ?     0.001  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space.norm     1024         1024         3  avgt   25        77.088 ?     9.303    B/op
>> testEncodeUTF8:?gc.count                            1024         1024         3  avgt   25      1973.000              counts
>> testEncodeUTF8:?gc.time                             1024         1024         3  avgt   25       996.000                  ms
>> 
>> enc
>>                                                  (count)  (maxLength)  (mySeed)  Mode  Cnt        Score       Error   Units
>> testEncodeUTF8                                      1024         1024         3  avgt   25        7.931 ?     0.006   ms/op
>> testEncodeUTF8:?gc.alloc.rate                       1024         1024         3  avgt   25      965.347 ?     0.736  MB/sec
>> testEncodeUTF8:?gc.alloc.rate.norm                  1024         1024         3  avgt   25  8430590.163 ?     7.213    B/op
>> testEncodeUTF8:?gc.churn.G1_Eden_Space              1024         1024         3  avgt   25      966.373 ?     5.248  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Eden_Space.norm         1024         1024         3  avgt   25  8439563.689 ? 47282.178    B/op
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space          1024         1024         3  avgt   25        0.007 ?     0.001  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space.norm     1024         1024         3  avgt   25       60.949 ?     8.405    B/op
>> testEncodeUTF8:?gc.count                            1024         1024         3  avgt   25     1715.000              counts
>> testEncodeUTF8:?gc.time                             1024         1024         3  avgt   25      888.000                  ms
>> 
>> stringBuilder
>>                                                  (count)  (maxLength)  (mySeed)  Mode  Cnt         Score       Error   Units
>> testEncodeUTF8                                      1024         1024         3  avgt   25         8.115 ?     0.110   ms/op
>> testEncodeUTF8:?gc.alloc.rate                       1024         1024         3  avgt   25      1259.267 ?    16.716  MB/sec
>> testEncodeUTF8:?gc.alloc.rate.norm                  1024         1024         3  avgt   25  11249391.875 ?     6.552    B/op
>> testEncodeUTF8:?gc.churn.G1_Eden_Space              1024         1024         3  avgt   25      1259.937 ?    17.232  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Eden_Space.norm         1024         1024         3  avgt   25  11255413.875 ? 43636.143    B/op
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space          1024         1024         3  avgt   25         0.007 ?     0.001  MB/sec
>> testEncodeUTF8:?gc.churn.G1_Survivor_Space.norm     1024         1024         3  avgt   25        59.461 ?     9.087    B/op
>> testEncodeUTF8:?gc.count                            1024         1024         3  avgt   25      2236.000              counts
>> testEncodeUTF8:?gc.time                             1024         1024         3  avgt   25      1089.000                  ms
>> The reason seems to be single char `StringBuilder.append()` that apart from range check does encoding check and stores `char` as two bytes in `byte[]` in ASB
>
> Surprising, but thanks for checking!

No need to merge in changes in master unless there are conflicts or you want to do more changes of your own, they will be merged automatically on integration. But it seems the bots need you to do /integrate again

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PR: https://git.openjdk.java.net/jdk/pull/1598