RFR: 8293499: Provide jmod --compress option [v4]
Jaikiran Pai
jpai at openjdk.org
Tue Sep 13 08:14:01 UTC 2022
On Tue, 13 Sep 2022 07:42:33 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:
>> I have been looking into `make clean-images images` performance, and realized jmod keeps compressing files with default compression level. Tuning that toward lighter compression levels improves build performance considerably, without a heavy loss in *.jmod sizes.
>>
>> This PR allows JMOD to select the compression level. Follow-ups would use this in the build system, see #10214.
>>
>> The interesting asymmetry against `jlink` is: `jlink` provides `--compress` option that only takes `2` for "ZIP compression". (Separately, we could argue if it would be beneficial to extend `--compress` to `jlink` as well, so to select the compression level there too.)
>
> Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision:
>
> More review comments
src/jdk.jlink/share/classes/jdk/tools/jmod/JmodOutputStream.java line 66:
> 64: private final ZipOutputStream zos;
> 65: private final LocalDateTime date;
> 66: private JmodOutputStream(OutputStream out, LocalDateTime date, int compLevel) {
Nit - I think this should be `compressLevel` just like the param name to the static method.
src/jdk.jlink/share/classes/jdk/tools/jmod/JmodTask.java line 1196:
> 1194: }
> 1195: try {
> 1196: int level = Integer.parseInt(value.substring(idx + 1));
If I'm reading this code correctly, then this call to `substring` can potentially end in a `IndexOutOfBoundsException` if the value is `zip-`. Perhaps add a check above to verify that `idx != value.length()`?
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PR: https://git.openjdk.org/jdk/pull/10213
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