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List:       openjdk-hotspot-runtime-dev
Subject:    Re: RFR 8069291: [TESTBUG] Fibonacci test: OutOfMemoryError: unable to	create native thread
From:       David Holmes <david.holmes () oracle ! com>
Date:       2015-02-24 2:17:13
Message-ID: 54EBDF29.6020006 () oracle ! com
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On 24/02/2015 2:13 AM, Dmitry Dmitriev wrote:
> Hello David,
>
> I ran this test in a loop 1000 times on two Arm devices and test never
> fail.
> I ran it on armv7 trimslice with ~900 Mb of memory for Java 9 fastdebug
> b52 and on armv5 with ~500 Mb of memory for Java 8u26 fastdebug b13.

Thanks Dmitry.

David

> Regards,
> Dmitry
>
> On 23.02.2015 4:53, David Holmes wrote:
>> On 19/02/2015 7:04 PM, Dmitry Dmitriev wrote:
>>> Hello David,
>>>
>>> Thank you for proposal. I was think about it, but finally decided to
>>> implement different fix. I leave the original thread creation logic, but
>>> exclude running this test on 32 bit JVM on Windows(via "@requires" jtreg
>>> tag).
>>
>> I'm surprised this is only an issue on Windows. I would expect our
>> smaller test devices to also struggle with this test.
>>
>> David
>>
>>> New open webrev:
>>> http://cr.openjdk.java.net/~ctornqvi/webrev/8069291/webrev.01/
>>> <http://cr.openjdk.java.net/%7Ectornqvi/webrev/8069291/webrev.01/>
>>> JBS Bug: https://bugs.openjdk.java.net/browse/JDK-8069291
>>>
>>> Regards,
>>> Dmitry
>>>
>>> On 17.02.2015 2:24, David Holmes wrote:
>>>> On 17/02/2015 7:31 AM, Dmitry Dmitriev wrote:
>>>>> Hi Christian,
>>>>>
>>>>> With this fix the N threads will be alive at the same time for N
>>>>> Fibonacci number. E.g. for 15th Fibonacci number at the same time
>>>>> will be 15 threads alive. Test takes small amount of time to run,
>>>>> less than a minute.
>>>>>
>>>>> But now I understand that for finding possible thread corruption it
>>>>> will be better to keep previous logic for creation threads. But in
>>>>> this case we need to limit maximum Fibonacci number for 32 bit
>>>>> systems to lower value, e.g. to 13. In this case only 751 threads
>>>>> will be created. For example 1973 threads are created for 15th
>>>>> Fibonacci number.
>>>>
>>>> So the usefulness of this seems to be as a stress test - in which case
>>>> scaling it back renders it less useful.
>>>>
>>>> I'm still inclined to treat the OOME as a transient error that may
>>>> affect some systems. Have the test not fail when that occurs if you
>>>> want to reduce testing noise.
>>>>
>>>> David
>>>>
>>>>> Thanks,
>>>>> Dmitry
>>>>>
>>>>> ----- Original Message -----
>>>>> From: christian.tornqvist@oracle.com
>>>>> To: dmitry.dmitriev@oracle.com, hotspot-runtime-dev@openjdk.java.net
>>>>> Sent: Tuesday, 17 February, 2015 12:02:44 AM GMT +03:00 Iraq
>>>>> Subject: RE: RFR 8069291: [TESTBUG] Fibonacci test: OutOfMemoryError:
>>>>> unable to    create native thread
>>>>>
>>>>> Hi Dmitry,
>>>>>
>>>>> How many threads will usually be alive at the same time? How long
>>>>> does the test usually take to run?
>>>>>
>>>>> Thanks,
>>>>> Christian
>>>>>
>>>>> -----Original Message-----
>>>>> From: hotspot-runtime-dev
>>>>> [mailto:hotspot-runtime-dev-bounces@openjdk.java.net] On Behalf Of
>>>>> Dmitry Dmitriev
>>>>> Sent: Friday, February 13, 2015 3:12 PM
>>>>> To: hotspot-runtime-dev@openjdk.java.net
>>>>> Subject: RFR 8069291: [TESTBUG] Fibonacci test: OutOfMemoryError:
>>>>> unable to create native thread
>>>>>
>>>>> Hello!
>>>>>
>>>>>
>>>>>
>>>>> Please review this fix for JDK-8069291. Unfortunately, the bug report
>>>>> isn't visible outside Oracle.
>>>>>
>>>>>
>>>>> This test calculates Fibonacci numbers "recursively" via threads and
>>>>> compares the result with the classical calculation. I correct
>>>>> out-of-memory error which sometimes occurred on 32 bit systems. I
>>>>> changed how the recursive threads are created. Now left & right
>>>>> branches creates separately and thread wait one branch to finish
>>>>> before creating thread for another branch.
>>>>>
>>>>>
>>>>> As part of the fixing the OOM issue I am moving the test to OpenJDK.
>>>>>
>>>>>
>>>>> Open webrev:
>>>>> http://cr.openjdk.java.net/~ctornqvi/webrev/8069291/webrev.00/
>>>>>
>>>>>
>>>>> JBS bug: https://bugs.openjdk.java.net/browse/JDK-8069291
>>>>>
>>>>>
>>>>> I run this test on all main platforms; Linux x64, Linux x32, Win x32,
>>>>> Win x64, MacOS x64, Solaris x64, Solaris Sparc64
>>>>>
>>>>>
>>>>> Thanks,
>>>>> Dmitry
>>>>>
>>>>>
>>>
>
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