8369392: Safepoint sync should suspend GC and Java threads concurrently

[pengxiaolong]

[86260096000ns] Safepoint synchronization initiated
[86260100708ns] Suspending GC threads
[86260101541ns] Blocking threads from starting/exiting
[86260102375ns] Arming safepoint using striped semaphore wait barrier
[86260103250ns] Setting thread local yield flag for threads
[86260111416ns] Blocking thread 0x0000000126190a10 [37151]
[86260111458ns] Blocking thread 0x000000012610ca10 [37663]
[86260121000ns] 23 total threads, waiting for 8 threads to block
[86260122208ns] Blocking thread 0x00000001261c9210 [42791]
[86260121083ns] Blocking thread 0x0000000172832c10 [38431]
[86260125041ns] Blocking thread 0x0000000125885210 [28459]
[86260125291ns] Blocking thread 0x000000012609fe10 [44071] 
[86260127041ns] Blocking thread 0x00000001261a9410 [64799]
[86260127958ns] Blocking thread 0x00000001261ce410 [35359]
[86260133041ns] Blocking thread 0x000000017281ba10 [39971] 
[86260125166ns] Blocking thread 0x000000017280ca10 [43819] 
[86260125166ns] Blocking thread 0x00000001260aa810 [37919]
[86260123333ns] Checking thread status
[86260149375ns] Thread 0x0000000125885210 [28459] is now blocked
[86260149708ns] Thread 0x00000001261ce410 [35359] is now blocked
[86260149833ns] Thread 0x00000001261c9210 [42791] is now blocked
[86260150125ns] Thread 0x000000012609fe10 [44071] is now blocked
[86260150375ns] Thread 0x00000001260aa810 [37919] is now blocked
[86260150583ns] Thread 0x000000017281ba10 [39971] is now blocked
[86260150833ns] Thread 0x000000017280ca10 [43819] is now blocked
[86260151041ns] Thread 0x0000000172832c10 [38431] is now blocked
[86260152041ns] Waiting for 1 GC threads to block 
[86262513166ns] All GC threads have been blocked
[86262520250ns] Safepoint synchronization complete

---

Progress

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• Commit message must refer to an issue

Issue

• JDK-8369392: Safepoint sync should suspend GC and Java threads concurrently (Enhancement - P4)

Reviewing

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Checkout this PR locally:
$ git fetch https://git.openjdk.org/jdk.git pull/27739/head:pull/27739
$ git checkout pull/27739

Update a local copy of the PR:
$ git checkout pull/27739
$ git pull https://git.openjdk.org/jdk.git pull/27739/head

Using Skara CLI tools

Checkout this PR locally:
$ git pr checkout 27739

View PR using the GUI difftool:
$ git pr show -t 27739

Using diff file

Download this PR as a diff file:
https://git.openjdk.org/jdk/pull/27739.diff

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[openjdk]

@pengxiaolong this pull request can not be integrated into master due to one or more merge conflicts. To resolve these merge conflicts and update this pull request you can run the following commands in the local repository for your personal fork:

git checkout JDK-8369392
git fetch https://git.openjdk.org/jdk.git master
git merge FETCH_HEAD
# resolve conflicts and follow the instructions given by git merge
git commit -m "Merge master"
git push