RFR: 8311163: Parallel: Improve large object handling during evacuation

[Albert Mingkun Yang]

On Tue, 27 Aug 2024 00:16:10 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

> Please review this change to ParallelGC young generation collection's handling
> of large objArrays, to now use the infrastructure provided by JDK-8253237 and
> JDK-8337709.  (That's the same infrastructure used by G1 young/mixed
> collections.)
> 
> Testing: mach5 tier1-5

Using `-Xmx3g -XX:+UseParallelGC -XX:ParallelGCThreads=6 DelayInducer.java`, I can see some regression (~10%) in avg gc-pause time on my box (nproc=12). Have you seen sth similar?


# baseline
[0.003s][info][gc] Using Parallel
[1.175s][info][gc] GC(0) Pause Young (Allocation Failure) 381M->299M(479M) 53.655ms
[1.432s][info][gc] GC(1) Pause Young (Allocation Failure) 424M->425M(676M) 185.065ms
[1.821s][info][gc] GC(2) Pause Young (Allocation Failure) 676M->676M(928M) 234.141ms
[2.171s][info][gc] GC(3) Pause Young (Allocation Failure) 927M->928M(1430M) 206.027ms
[7.367s][info][gc] GC(4) Pause Young (Allocation Failure) 1814M->1809M(2312M) 631.159ms
[8.217s][info][gc] GC(5) Pause Full (Allocation Failure) 2311M->732M(2105M) 547.506ms
[10.453s][info][gc] GC(6) Pause Young (Allocation Failure) 1074M->1068M(2105M) 162.718ms
[11.581s][info][gc] GC(7) Pause Young (Allocation Failure) 1410M->994M(2105M) 157.642ms
[12.400s][info][gc] GC(8) Pause Young (Allocation Failure) 1336M->926M(2105M) 114.424ms


# new
[0.002s][info][gc] Using Parallel
[1.176s][info][gc] GC(0) Pause Young (Allocation Failure) 381M->299M(479M) 59.968ms
[1.415s][info][gc] GC(1) Pause Young (Allocation Failure) 425M->425M(676M) 167.393ms
[1.771s][info][gc] GC(2) Pause Young (Allocation Failure) 676M->676M(928M) 199.576ms
[2.151s][info][gc] GC(3) Pause Young (Allocation Failure) 927M->928M(1430M) 236.868ms
[7.397s][info][gc] GC(4) Pause Young (Allocation Failure) 1814M->1809M(2312M) 689.166ms
[8.299s][info][gc] GC(5) Pause Full (Allocation Failure) 2311M->732M(2106M) 603.035ms
[10.560s][info][gc] GC(6) Pause Young (Allocation Failure) 1074M->1068M(2106M) 218.286ms
[11.710s][info][gc] GC(7) Pause Young (Allocation Failure) 1410M->994M(2106M) 183.299ms
[12.590s][info][gc] GC(8) Pause Young (Allocation Failure) 1336M->926M(2106M) 181.675ms

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PR Comment: https://git.openjdk.org/jdk/pull/20720#issuecomment-2312172195