The gc/z/TestHighUsage.java was originally used to test the high usage heuristics rule for single generational ZGC. For generational ZGC this test does not test anything concrete and mostly produces noise. So it should be removed.

--- Original ---
Generational ZGC: gc/z/TestHighUsage.java Allocation Stall' found in stdout
The following test timed out in the JDK21 CI with Generational ZGC:

gc/z/TestHighUsage.java

Here's a log file snippet for the jdk-21+24-2090-tier2 sighting:

Free: 2M (Idling)
Free: 2M (Idling)
Free: 2M (Idling)
[67.420s][info][gc] GC(48) Minor Collection (Allocation Rate)
[67.425s][info][gc] Allocation Stall (C1 CompilerThread0) 4.926ms
[67.426s][info][gc] GC(48) Minor Collection (Allocation Rate) 128M(100%)->128M(100%) 0.006s
[67.680s][info][gc] GC(49) Minor Collection (Allocation Stall)
[67.685s][info][gc] GC(49) Minor Collection (Allocation Stall) 128M(100%)->128M(100%) 0.005s
[67.686s][info][gc] GC(50) Major Collection (Allocation Stall)
[67.691s][info][gc] Allocation Stall (main) 10.879ms
[67.696s][info][gc] GC(51) Minor Collection (Allocation Stall)
[67.702s][info][gc] GC(51) Minor Collection (Allocation Stall) 128M(100%)->128M(100%) 0.006s
[67.710s][info][gc] GC(52) Minor Collection (Allocation Stall)
[67.715s][info][gc] GC(52) Minor Collection (Allocation Stall) 128M(100%)->128M(100%) 0.005s
[67.861s][info][gc] Relocation Stall (main) 0.076ms
[67.861s][info][gc] Allocation Stall (Common-Cleaner) 150.476ms
[67.861s][info][gc] Allocation Stall (main) 169.246ms
Free: 0M (Idling)
[67.861s][info][gc] GC(50) Major Collection (Allocation Stall) 128M(100%)->118M(92%) 0.175s
Free: 10M (Allocating)
Free: 10M (Allocating)
Free: 10M (Allocating)
Free: 10M (Allocating)
[68.900s][info][gc] GC(53) Minor Collection (Allocation Rate)
[68.905s][info][gc] GC(53) Minor Collection (Allocation Rate) 120M(94%)->114M(89%) 0.006s
Free: 12M (Allocating)
Free: 12M (Allocating)
Free: 12M (Allocating)

<snip>

Free: 10M (Allocating)
Free: 10M (Allocating)
Free: 10M (Allocating)
Free: 8M (Allocating)
[80.585s][info][gc] GC(55) Minor Collection (Allocation Rate)
[80.591s][info][gc] GC(55) Minor Collection (Allocation Rate) 120M(94%)->116M(91%) 0.005s
Done
];
 stderr: []
 exitValue = 0

java.lang.RuntimeException: 'Allocation Stall' found in stdout
at jdk.test.lib.process.OutputAnalyzer.shouldNotContain(OutputAnalyzer.java:267)
at gc.z.TestHighUsage.main(TestHighUsage.java:97)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:103)
at java.base/java.lang.reflect.Method.invoke(Method.java:578)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1583)

JavaTest Message: Test threw exception: java.lang.RuntimeException: 'Allocation Stall' found in stdout
JavaTest Message: shutting down test

STATUS:Failed.`main' threw exception: java.lang.RuntimeException: 'Allocation Stall' found in stdout
----------rerun:(41/5954)*----------