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List:       openjdk-hotspot-runtime-dev
Subject:    Re: RFR 8161696 [TESTBUG] runtime/StackGuardPages/testme.sh uses invalid argument -Xss328k
From:       Gerald Thornbrugh <gerald.thornbrugh () oracle ! com>
Date:       2016-07-29 15:15:49
Message-ID: 579B7325.8030908 () oracle ! com
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Hi Dan,

Thanks.

Jerry
> Thumbs up.
>
> Dan
>
>
> On 7/28/16 10:49 AM, Gerald Thornbrugh wrote:
>> Hi Everyone,
>>
>> Here is the new webrev with the 1M change:
>>
>> http://cr.openjdk.java.net/~gthornbr/8161696/hotspot-webrev.02/ 
>> <http://cr.openjdk.java.net/%7Egthornbr/8161696/hotspot-webrev.02/>
>>
>> Please let me know if you have questions or concerns.
>>
>> Thanks,
>>
>> jerry
>>> On 27/07/2016 11:48 PM, Gerald Thornbrugh wrote:
>>>> Hi Fred,
>>>>
>>>> Thanks for the information.
>>>>
>>>> How does everyone feel about implementing Fred's suggestion of a stack
>>>> size of 1MB?
>>>> As Fred states this not a complete fix but it would provide relief 
>>>> from
>>>> this issue for the foreseeable future.
>>>
>>> I can live with it but I think it is unnecessary.
>>>
>>> Thanks,
>>> David
>>>
>>>>
>>>> Thanks,
>>>>
>>>> Jerry
>>>>> Hi Jerry,
>>>>>
>>>>> On 26/07/2016 22:55, Gerald Thornbrugh wrote:
>>>>>> Hi David,
>>>>>>> Hi Jerry,
>>>>>>>
>>>>>>> On 27/07/2016 2:06 AM, Gerald Thornbrugh wrote:
>>>>>>>> Hi Everyone,
>>>>>>>>
>>>>>>>> I would like to have the following change reviewed:
>>>>>>>>
>>>>>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8161696
>>>>>>>>
>>>>>>>> Webrev:http://cr.openjdk.java.net/~gthornbr/8161696/hotspot-webrev.01/ 
>>>>>>>>
>>>>>>>> <http://cr.openjdk.java.net/%7Egthornbr/8161696/hotspot-webrev.01/> 
>>>>>>>>
>>>>>>>>
>>>>>>>> The stack size for this test needs to be increased to 384K for 
>>>>>>>> some
>>>>>>>> platforms.
>>>>>>>
>>>>>>> Is there a specific reason we set -Xss in the first place 
>>>>>>> instead of
>>>>>>> just taking the platform defaults? If the platform stack settings
>>>>>>> change this test may need updating again.
>>>>>>
>>>>>> It was my understand (maybe incorrectly) that setting -Xss was an
>>>>>> attempt to limit the memory and time
>>>>>> resources the test takes.  Using the smallest stack size 
>>>>>> allowable will
>>>>>> allocate less memory and reduce the
>>>>>> amount of time the test takes.  Since I think Fred wrote the test he
>>>>>> would know better than I would.
>>>>>>
>>>>>> Fred, what is the reason behind specifying "-Xss" for this test?
>>>>>
>>>>> I'm not the author of this test, but I can try to contribute my
>>>>> two cents.
>>>>>
>>>>> I'm not seeing any particular reason to limit the stack size to
>>>>> 320KB other than reducing time and resources required for this
>>>>> test.
>>>>>
>>>>> Looking at the test history, Dmitry did the current version of the
>>>>> test, but the "-Xss320k" argument was already there before Dmitry
>>>>> re-wrote the test to fix 8042155. So it looks like a relic from
>>>>> old code for which the rational has been lost.
>>>>>
>>>>> Regarding the test, limiting the stack size looks a good idea to
>>>>> avoid wasting too much time and resources during testing. However,
>>>>> I'm seeing to reason to make the stack size "as small as possible".
>>>>> A 1MB stack size could already provide efficient improvement while
>>>>> avoiding platform dependent stack size constraint (and I'll be
>>>>> cursed for this by next generations of HotSpot developer as a
>>>>> 1MB limitation could become completely unjustified in the future).
>>>>>
>>>>> Fred
>>>>>
>>>>>> I have thought about the test harness setting an environment 
>>>>>> variable
>>>>>> and/or a java property to the correct
>>>>>> minimum values for "-Xss" depending upon the architecture the 
>>>>>> test is
>>>>>> running on.  The tests could then use
>>>>>> the value to start each test. That way each test could be 
>>>>>> tailored for
>>>>>> the specific architecture. After looking into
>>>>>> this it looks the implementation would be significant and would be
>>>>>> outside the scope of this bug fix.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Jerry
>>>>>>>
>>>>>>> Thanks,
>>>>>>> David
>>>>>>>
>>>>>>>> My fix for JDK-8081770
>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8081770
>>>>>>>> moved the functionality
>>>>>>>> from the testme.sh script to exeinvoke.c so the dependency for 
>>>>>>>> a local
>>>>>>>> compiler could be removed.
>>>>>>>> Because of this the stack size change needs to be applied to
>>>>>>>> exeinvoke.c
>>>>>>>> file instead of the testme.sh file.
>>>>>>>>
>>>>>>>> Please let me know if you have any questions or concerns.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Jerry
>>>>>>
>>>>
>>
>

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