RFR: 8299748: java/util/zip/Deinflate.java failing on s390x [v2]

[Jaikiran Pai]

On Thu, 2 Feb 2023 08:27:55 GMT, Amit Kumar <amitkumar at openjdk.org> wrote:

>> DeInflate.java test fails on s390x platform because size for out1 array which is responsible for storing the compressed data is insufficient. And being unable to write whole compressed data on array, on s390 whole data can't be recovered after compression. So this fix increase Array size (for s390).
>
> Amit Kumar has updated the pull request incrementally with one additional commit since the last revision:
> 
>   change acc to Alan comments

> I guess this is what you want to see ?
>
>
>    level:1, strategy: 0, dowrap: false
>      required size: 553018  <- there is an issue

Yes, thank you. So to summarize, an input of size `524288` bytes gets "compressed"/deflated to a size of `553018` i.e. it _adds_ `28730` bytes, when level 1 deflater level (`BEST_SPEED`) is used and the custom zlib's hardware instruction is triggered. That, in my opinion, is odd (adding that many additional bytes for compressed data). So I think it would be good to get the team which did the zlib change involved in this discussion to understand if this large an impact is expected. And if so, is it for all inputs or if there's some issue that needs to be looked into in the implementation. Would you or someone in your team be able to get their attention to this?

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PR: https://git.openjdk.org/jdk/pull/12283