RFR(XS) Contended Locking speedup PlatformEvent unpark bucket (8061552)

[Daniel D. Daugherty]

Thanks!

Dan


On 10/28/14 8:42 PM, David Holmes wrote:
> Thanks for clarifying things Dan.
>
> Good to go.
>
> David
>
> On 29/10/2014 2:09 AM, Daniel D. Daugherty wrote:
>> On 10/28/14 1:33 AM, David Holmes wrote:
>>> Hi Dan,
>>
>> David, Thanks for the review!
>>
>>
>>> On 28/10/2014 8:34 AM, Daniel D. Daugherty wrote:
>>>> Greetings,
>>>>
>>>> I have the Contended Locking speedup PlatformEvent unpark bucket
>>>> ready for review. These are small comment only changes that have
>>>> already been reviewed by Karen Kinnear (acorn) and Dave Dice (dice).
>>>> It would be good to get one or two more pair of eyes on these
>>>> comment additions/updates/synchronizations.
>>>
>>> So there's a bit of cross-platform inconsistency. For example you
>>> deleted the TO-DO/FIXME chunk of comments on Solaris but left them on
>>> Windows. Granted parts are different (and my not be true/relevant any
>>> more) but parts are basically the same eg:
>>>
>>> -  Reconcile Doug's JSR166 j.u.c park-unpark with the objectmonitor
>>> implementation.
>>>
>>> -  Collapse the JSR166 parker event, and the objectmonitor ParkEvent
>>> into a single "Event" construct.
>>
>> You're right about this deletion inconsistency. I didn't finish
>> running down the details about this particular deletion. I have
>> to chase that down with Dave Dice and Karen Kinnear and that will
>> take some time so it won't be done as part of this fix.
>>
>>
>>
>>> Also linux/bsd have the transition information only in the park/unpark
>>> functions, but solaris and windows have it both in the functions and
>>> as part of the preeamble - which seems redundant to me.
>>
>> Solaris and Windows have a big introductory comment that is similar,
>> but not the same between those two platforms. Linux has a reference
>> to the Solaris introductory comment:
>>
>> 5404 // Refer to the comments in os_solaris.cpp park-unpark.
>>
>> and BSD inherited that reference comment from Linux...
>>
>> We're trying to figure out the best way to reconcile this type of
>> common introductory comment, but that will be handled separately.
>> I'm discussing the issue with Jerry Thornbrugh as part of his *NIX
>> work and with both Dave Dice and Karen Kinnear to make sure that
>> we don't lose anything important.
>>
>>
>>> Also os_aix.cpp is missing, but is presumably similar to the linux/bsd
>>> cases.
>>
>> AIX is actually missing many of the bug fixes from 2012.12/2013.01
>> bug_fix bucket work. It looks like the AIX project based their work
>> on earlier versions of os_linux.cpp, but didn't keep track of the
>> changes to os_linux.cpp afterward... Our plan is to go through all
>> of the bugs associated with this project and file new AIX specific
>> bugs for fixes that are missing.
>>
>> Thanks again for the review!
>>
>> Dan
>>
>>
>>>
>>> Cheers,
>>> David
>>>
>>>> Historial reminder:
>>>>
>>>>      Back in 2012.12 and 2013.01, work on the "bug fix bucket" for the
>>>>      Contended Locking project was being done. One of the bug fixes 
>>>> was:
>>>>
>>>>      JDK-8004902 correctness fixes motivated by contended locking work
>>>> (6607129)
>>>>      https://bugs.openjdk.java.net/browse/JDK-8004902
>>>>
>>>>      The work on JDK-8004902 picked up all of the code changes and
>>>> many of
>>>>      comments that were part of this bucket (speedup PlatformEvent
>>>> unpark).
>>>>
>>>>      Here's the webrev for "bug fix bucket":
>>>>
>>>> http://cr.openjdk.java.net/~dcubed/cl_bug_fix_bucket-webrev/2/
>>>>
>>>>      The bug fix bucket included fixes for 6444286, 8004902 and 
>>>> 8004903,
>>>>      but the majority of the work was done for 8004902. Now back to 
>>>> the
>>>>      current thread...
>>>>
>>>> This work is being tracked by the following bug ID:
>>>>
>>>>      JDK-8061552 Contended Locking speedup PlatformEvent unpark bucket
>>>>      https://bugs.openjdk.java.net/browse/JDK-8061552
>>>>
>>>> Here is the webrev URL:
>>>>
>>>> http://cr.openjdk.java.net/~dcubed/8061552-webrev/2-jdk9-hs-rt/
>>>>
>>>> Here is the JEP link:
>>>>
>>>>      https://bugs.openjdk.java.net/browse/JDK-8046133
>>>>
>>>> Testing:
>>>>
>>>> - JPRT test jobs
>>