My Probably last attempt to optimize performance

[PanagiotisDrakatos]

Check List:

• [ ] You have run ./mvnw verify and the project builds successfully

• [ ] Tests pass (./test.sh <username> shows no differences between expected and actual outputs)

• [ ] All formatting changes by the build are committed

• [ ] Your launch script is named calculate_average_<username>.sh (make sure to match casing of your GH user name) and is executable

• [ ] Output matches that of calculate_average_baseline.sh

• [ ] For new entries, or after substantial changes: When implementing custom hash structures, please point to where you deal with hash collisions (line number)

• Execution time:

• Execution time of reference implementation:

[PanagiotisDrakatos]

@gunnarmorling please check again i believe this is my last attempt to improve performance after that my capabilities are limited

[gunnarmorling]

Runs out of heap space for the tests on 32 cores:

Caused by: java.lang.OutOfMemoryError: Java heap space
    at dev.morling.onebrc.CalculateAverage_PanagiotisDrakatos$MeasurementRepository.<init>(CalculateAverage_PanagiotisDrakatos.java:274)
    at dev.morling.onebrc.CalculateAverage_PanagiotisDrakatos.MappingByteBufferToData(CalculateAverage_PanagiotisDrakatos.java:164)
    at dev.morling.onebrc.CalculateAverage_PanagiotisDrakatos$$Lambda/0x00007f6b43001860.apply(Unknown Source)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
    at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
    at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1708)
    at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
    at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
    at java.base/java.util.stream.ReduceOps$ReduceTask.doLeaf(ReduceOps.java:960)
    at java.base/java.util.stream.ReduceOps$ReduceTask.doLeaf(ReduceOps.java:934)
    at java.base/java.util.stream.AbstractTask.compute(AbstractTask.java:327)
    at java.base/java.util.concurrent.CountedCompleter.exec(CountedCompleter.java:754)
    at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:387)
    at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1312)
    at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1843)
    at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1808)
    at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:188)

[PanagiotisDrakatos]

@gunnarmorling i fixed VM options arguments and increased the xmx. Probably it would not failed now

[gunnarmorling]

Looking good now: 00:05.559. Passing for 10K keys, too.