RFR: JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort) [v12]

[Laurent Bourgès]

On Mon, 14 Mar 2022 19:12:29 GMT, iaroslavski <duke at openjdk.java.net> wrote:

>> Sorting:
>> 
>> - adopt radix sort for sequential and parallel sorts on int/long/float/double arrays (almost random and length > 6K)
>> - fix tryMergeRuns() to better handle case when the last run is a single element
>> - minor javadoc and comment changes
>> 
>> Testing:
>> - add new data inputs in tests for sorting
>> - add min/max/infinity values to float/double testing
>> - add tests for radix sort
>
> iaroslavski has updated the pull request incrementally with one additional commit since the last revision:
> 
>   JDK-8266431: Dual-Pivot Quicksort improvements (Radix sort)
>   
>   * Improved mixed insertion sort
>   * Optimized insertion sort
>   * Improved merging sort
>   * Optimized soring tests

I checked the latest code: line 128:

Max length of additional buffer, limited by max_heap / 64 or 256mb elements (2gb max).
    
    private static final int MAX_BUFFER_LENGTH =
            (int) Math.min(Runtime.getRuntime().maxMemory() >> 6, 256L << 20);

So the current upper limit concerns the max length = max_heap_bytes / 64 (max heap/8) or 2gb (if heap is huge).

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