RFR 8073124: Tune test and document TimSort runs length stack size increase

[David Holmes]

On 14/02/2015 12:03 AM, Lev Priima wrote:
> Please review and push:
> http://cr.openjdk.java.net/~lpriima/8073124/webrev.00/
> bug: https://bugs.openjdk.java.net/browse/JDK-8073124

I hadn't realized 8072909 had been pushed without final reviewer 
comments being addressed. :(

These changes seem okay. I hope they get promoted at the same time as 
the original changeset so we don't get test failures.

Thanks,
David

> Lev
>
> On 02/13/2015 05:20 AM, David Holmes wrote:
>> Hi Lev,
>>
>> On 13/02/2015 2:56 AM, Lev Priima wrote:
>>> Christos,
>>>
>>> Test may fail on shorter arrays(page 8 of paper). For instance, on worst
>>> case, generated by test, it starts to fail on length 67108864.
>>> After increasing stack size of runs to merge, Arrays.sort(T[]) works
>>> also on maximum possible array for HotSpot JVM.
>>
>> I'd also like to see this documented somewhere in the code. Presently
>> there is a reference to listsort.txt but then you have to go and find
>> it on the web. :( At a minimum could we please add:
>>
>>  175          * computation below must be changed if MIN_MERGE is
>> decreased.  See
>>  176          * the MIN_MERGE declaration above for more information.
>> +             * The maximum value of 49 allows for an array up to length
>> +             * Integer.MAX_VALUE-4.
>>
>>> Roger, David,
>>> I've updated the test (
>>> http://cr.openjdk.java.net/~lpriima/8072909/webrev.01/test/java/util/Arrays/TimSortStackSize2.java.html
>>>
>>> ) to make it more suitable for regular execution:
>>>
>>>    27  * @run main/othervm TimSortStackSize2 67108864
>>
>> This will still fail on small memory devices:
>>
>> :~> java TimSortStackSize2 67108864
>> Exception in thread "main" java.lang.OutOfMemoryError: Java heap space
>>
>> as the default heap ergonomics may not be large enough. I had to add a
>> minimum heap of -Xmx385M to get it to run.
>>
>> Thanks,
>> David
>>
>>>    28  * not for regular execution on all platforms:
>>>    29  * run main/othervm -Xmx8g TimSortStackSize2 1073741824
>>>    30  * run main/othervm -Xmx32g TimSortStackSize2 2147483644
>>>
>>> Could you please push this:
>>> http://cr.openjdk.java.net/~lpriima/8072909/webrev.01/
>>> ?
>>>
>>> Lev
>>>
>>> On 02/12/2015 12:54 PM, christos at zoulas.com wrote:
>>>> On Feb 12, 9:57pm,david.holmes at oracle.com  (David Holmes) wrote:
>>>> -- Subject: Re: 8072909: TimSort fails with
>>>> ArrayIndexOutOfBoundsException on
>>>>
>>>> | Ok - thanks Lev!
>>>> |
>>>> | David
>>>>
>>>> For posterity can someone document this, and also the value for which
>>>> Integer.MAX_VALUE-4 fails?
>>>>
>>>> christos
>>>
>