RFR: 8253064: monitor list simplifications and getting rid of TSM [v3]

[Daniel D. Daugherty]

On 11/9/20 6:25 PM, David Holmes wrote:
> On Mon, 9 Nov 2020 20:51:17 GMT, Daniel D. Daugherty <dcubed at openjdk.org> wrote:
>
>>> Changes from @fisk and @dcubed-ojdk to:
>>>
>>> - simplify ObjectMonitor list management
>>> - get rid of Type-Stable Memory (TSM)
>>>
>>> This change has been tested with Mach5 Tier[1-3],4,5,6,7,8; no new regressions.
>>> Aurora Perf runs have also been done (DaCapo-h2, Quick Startup/Footprint,
>>> SPECjbb2015-Tuned-G1, SPECjbb2015-Tuned-ParGC, Volano)
>>>    - a few minor regressions (<= -0.24%)
>>>    - Volano is 6.8% better
>>>
>>> Eric C. has also done promotion perf runs on these bits and says "the results look fine".
>> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
>>
>>    Resolve more @dholmes-ora comments with help from @fisk.
> src/hotspot/share/runtime/synchronizer.cpp line 89:
>
>> 87:   ObjectMonitor* head = Atomic::load_acquire(&_head);
>> 88:   ObjectMonitor* m = head;
>> 89:   do {
> This wasn't the loop I was referring to. It is the while loop below this at line 93.

The PR is showing comments from you for both while loops.

And at this point, both have been tweaked...

Dan


>
> -------------
>
> PR: https://git.openjdk.java.net/jdk/pull/642