Fwd: Re: Request for Review (s) - 8133023: ParallelGCThreads is not calculated correctly

[David Holmes]

Hi Jon,

On 1/12/2015 3:00 AM, Jon Masamitsu wrote:
> On 11/25/2015 06:11 PM, David Holmes wrote:
>> Hi Jon,
>>
>> We already have VM_Version::early_initialize() that can/should be used
>> for this if possible.
>
> David,
>
> Thanks for looking at this.  I tried to use early_initialize() but found
> that I needed to add empty early_initialize() methods for nearly
> all the platforms. The code I wanted to move was in os_solaris.cpp
> (from the os_init() to the early_initialize()), which made me add an
> early_initialize() for solaris x86 which seemed to require I add
> an early_initialize() to vm_version_x86.hpp which lead me to
> add empty early_initialize()  for all the x86 platforms.

Yes it does work that way. VM_Version is defined in cpu specific 
headers, then implemented by os_cpu specific .cpp files. So if you want 
an os specific early_initialize it will have to be applied to all cpu/os 
combinations for which your os has a given cpu implementation.

But you've added your own VM_Version function in a similar way, so how 
is this working out any differently ?? (Note your change would also 
impact a linux/sparc port).

David
-----

>
> http://cr.openjdk.java.net/~jmasa/8133023/webrev.01/
>
> Jon
>>
>> Thanks,
>> David
>>
>> On 26/11/2015 8:50 AM, Jon Masamitsu wrote:
>>> Widening the review request.  This fixed changed the order
>>> of some VM initialization for solaris-sparc with hopefully
>>> the minimum change for other platforms.
>>>
>>> Thanks.
>>>
>>> Jon
>>>
>>> -------- Forwarded Message --------
>>> Subject:     Re: Request for Review (s) - 8133023: ParallelGCThreads is
>>> not calculated correctly
>>> Date:     Wed, 25 Nov 2015 14:10:36 -0800
>>> From:     Jon Masamitsu <jon.masamitsu at oracle.com>
>>> Organization:     Oracle Corporation
>>> To:     hotspot-gc-dev at openjdk.java.net
>>>
>>>
>>>
>>> I have a new fix for this bug.  My previous fix broke solaris-x86 (I
>>> had not defined an early_initialize() for x86).  This fix is slightly
>>> smaller and has the virtue of moving the required initialization
>>> closer to where it is used.
>>>
>>> http://cr.openjdk.java.net/~jmasa/8133023/webrev.03/index.html
>>>
>>> Testing: JPRT build on all platforms, checked by hand that the correct
>>> number
>>> of GC worker threads are created on later Niagara platforms.
>>>
>>> Thanks.
>>>
>>> Jon
>>>
>>> On 11/12/2015 1:31 PM, Jon Masamitsu wrote:
>>>> GC calls VM_Version::calc_parallel_worker_threads() to determine
>>>> the number of GC threads to create.  On Sparc it checks for newer
>>>> Niagara hardware to decide the proper scaling of the GC threads with
>>>> the hardware threads. calc_parallel_worker_threads() was being called
>>>> before enough information was gathered to determine the Sparc hardware.
>>>>
>>>> Moved the gathering of information needed to earlier in the JVM
>>>> initialization.
>>>>
>>>> http://cr.openjdk.java.net/~jmasa/8133023/webrev.00/
>>>>
>>>> https://bugs.openjdk.java.net/browse/JDK-8133023
>>>>
>>>> Thanks.
>>>>
>>>> Jon
>>>
>>>
>>>
>