RFR: 8305670: Performance regression in LockSupport.unpark with lots of idle threads [v4]

[David Holmes]

On Thu, 27 Apr 2023 02:11:40 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Daniel D. Daugherty has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   8305670.with-rehn-quick-mode.cr3.patch
>
> src/hotspot/share/prims/unsafe.cpp line 791:
> 
>> 789:     // early life stage of the JavaThread* is protected.
>> 790:     FastThreadsListHandle ftlh(thread_oop, java_lang_Thread::thread(thread_oop));
>> 791:     JavaThread* thr = ftlh.protected_java_thread();
> 
> I find this obscures things more than it aids understanding in this case. You don't need a special FTLH to get the desired semantics here.

Note this is just a comment I'm not requesting you change it back.

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PR Review Comment: https://git.openjdk.org/jdk/pull/13519#discussion_r1178557380