RFR: 8347167: Implementation in com.sun.net.httpserver.Headers.normalize() can be improved [v2]

[Volkan Yazici]

On Mon, 17 Nov 2025 16:06:55 GMT, Josiah Noel <duke at openjdk.org> wrote:

>> Following the direction outlined in the net-dev discussion, I've updated the `com.sun.net.httpserver.Headers.normalize()` method to no longer allocate a superfluous char array when the header is already normalized.
>
> Josiah Noel has updated the pull request incrementally with one additional commit since the last revision:
> 
>   patch

Attaching the benchmark results for the record:


$ git merge upstream/master
$ make run-test TEST="micro:HeaderNormalization" MICRO="OPTIONS=-prof gc
Benchmark                                            (key)  Mode  Cnt     Score     Error   Units
HeaderNormalization.n25                     Accept-charset  avgt   15    12.673 ±   0.248   ns/op
HeaderNormalization.n25:gc.alloc.rate       Accept-charset  avgt   15  7826.300 ± 154.610  MB/sec
HeaderNormalization.n25:gc.alloc.rate.norm  Accept-charset  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n25:gc.count            Accept-charset  avgt   15    82.000            counts
HeaderNormalization.n25:gc.time             Accept-charset  avgt   15    61.000                ms
HeaderNormalization.n25                     accept-charset  avgt   15    12.728 ±   0.277   ns/op
HeaderNormalization.n25:gc.alloc.rate       accept-charset  avgt   15  7793.079 ± 170.106  MB/sec
HeaderNormalization.n25:gc.alloc.rate.norm  accept-charset  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n25:gc.count            accept-charset  avgt   15    87.000            counts
HeaderNormalization.n25:gc.time             accept-charset  avgt   15    62.000                ms
HeaderNormalization.n25                     Accept-Charset  avgt   15    12.491 ±   0.273   ns/op
HeaderNormalization.n25:gc.alloc.rate       Accept-Charset  avgt   15  7940.943 ± 173.267  MB/sec
HeaderNormalization.n25:gc.alloc.rate.norm  Accept-Charset  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n25:gc.count            Accept-Charset  avgt   15    86.000            counts
HeaderNormalization.n25:gc.time             Accept-Charset  avgt   15    67.000                ms
HeaderNormalization.n25                     ACCEPT-CHARSET  avgt   15    12.783 ±   0.222   ns/op
HeaderNormalization.n25:gc.alloc.rate       ACCEPT-CHARSET  avgt   15  7758.515 ± 132.436  MB/sec
HeaderNormalization.n25:gc.alloc.rate.norm  ACCEPT-CHARSET  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n25:gc.count            ACCEPT-CHARSET  avgt   15    91.000            counts
HeaderNormalization.n25:gc.time             ACCEPT-CHARSET  avgt   15    64.000                ms
HeaderNormalization.n26                     Accept-charset  avgt   15     7.871 ±   0.056   ns/op
HeaderNormalization.n26:gc.alloc.rate       Accept-charset  avgt   15     0.007 ±   0.001  MB/sec
HeaderNormalization.n26:gc.alloc.rate.norm  Accept-charset  avgt   15    ≈ 10⁻⁴              B/op
HeaderNormalization.n26:gc.count            Accept-charset  avgt   15       ≈ 0            counts
HeaderNormalization.n26                     accept-charset  avgt   15    12.864 ±   0.225   ns/op
HeaderNormalization.n26:gc.alloc.rate       accept-charset  avgt   15  7709.843 ± 136.491  MB/sec
HeaderNormalization.n26:gc.alloc.rate.norm  accept-charset  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n26:gc.count            accept-charset  avgt   15    81.000            counts
HeaderNormalization.n26:gc.time             accept-charset  avgt   15    60.000                ms
HeaderNormalization.n26                     Accept-Charset  avgt   15    15.299 ±   0.407   ns/op
HeaderNormalization.n26:gc.alloc.rate       Accept-Charset  avgt   15  6485.181 ± 174.316  MB/sec
HeaderNormalization.n26:gc.alloc.rate.norm  Accept-Charset  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n26:gc.count            Accept-Charset  avgt   15   120.000            counts
HeaderNormalization.n26:gc.time             Accept-Charset  avgt   15    77.000                ms
HeaderNormalization.n26                     ACCEPT-CHARSET  avgt   15    13.601 ±   0.347   ns/op
HeaderNormalization.n26:gc.alloc.rate       ACCEPT-CHARSET  avgt   15  7294.108 ± 185.918  MB/sec
HeaderNormalization.n26:gc.alloc.rate.norm  ACCEPT-CHARSET  avgt   15   104.000 ±   0.001    B/op
HeaderNormalization.n26:gc.count            ACCEPT-CHARSET  avgt   15   117.000            counts
HeaderNormalization.n26:gc.time             ACCEPT-CHARSET  avgt   15    78.000                ms

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

PR Comment: https://git.openjdk.org/jdk/pull/27276#issuecomment-3547472395