RFR: JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort)

[Richard Startin]

On Tue, 14 Sep 2021 10:57:17 GMT, Alan Bateman <alanb at openjdk.org> wrote:

>>> Hi @iaroslavski I'm unconvinced that this work was from 14/06/2020 - I believe this work derives from an unsigned radix sort I implemented on 10/04/2021 [richardstartin/radix-sort-benchmark at ab4da23#diff-6c13d3fb74f38906677dbfa1a70a123c8e5baf4a39219c81ef121e078d0013bcR226](https://github.com/richardstartin/radix-sort-benchmark/commit/ab4da230e1d0ac68e5ee2cee38d71c7e7d50f49b#diff-6c13d3fb74f38906677dbfa1a70a123c8e5baf4a39219c81ef121e078d0013bcR226) which has numerous structural similarities to this work:
>>> Moreover, @bourgesl forked my repository on 11/04/2021 and communicated with me about doing so. On 25/04/2021 there was a new implementation of `DualPivotQuicksort` with a signed radix sort but the same structural similarities, and with the same method and variable names in places [bourgesl/radix-sort-benchmark at 90ff7e4#diff-397ce8fd791e2ce508cf9127201bc9ab46264cd2a79fd0487a63569f2e4b59b2R607-R609](https://github.com/bourgesl/radix-sort-benchmark/commit/90ff7e427da0fa49f374bff0241fb2487bd87bde#diff-397ce8fd791e2ce508cf9127201bc9ab46264cd2a79fd0487a63569f2e4b59b2R607-R609)
>> 
>> @iaroslavski The attribution is not clear here. Can you provide a summary as to who is contributing to this patch? I can't tell if all involved have signed the OCA or not. I'm sure there will be questions about space/time trade-offs with radix sort but I think it's important to first establish the origins of this patch first.
>
>> @AlanBateman Vertical pipeline of PR hides comments in the middle and you have to click on "Show more..." to see all comments. There are no claims related to the origin of my patch, it doesn't violate any rights.
> 
> There is a comment from richardstartin suggesting that something was derived from code in his repo. Is this a benchmark that is not part of this PR? Only asking because I can't find him on OCA signatories. You can use the Skara /contributor command to list the contributors.

@AlanBateman my claim was that the implementation was derived from my implementation, and demonstrated a sequence of name changes after @bourgesl forked my repository containing a structurally similar radix sort implementation and benchmarks, in order to provide circumstantial evidence for my claim. Via email @iaroslavski told me that this was not the case, which I decided to accept at face value. So please judge this PR on its merits, and disregard the claims made in these comments. I have not signed an OCA but do not want to block this PR if the space time tradeoff is deemed acceptable.

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PR: https://git.openjdk.java.net/jdk/pull/3938