The following test timed out in the JDK16 CI:

java/foreign/TestMismatch.java

Here's a snippet from the log file:

#section:testng
----------messages:(7/278)----------
command: testng TestMismatch
reason: User specified action: run testng TestMismatch
Mode: othervm [test needs --add-modules]
Additional options from @modules: --add-modules jdk.incubator.foreign
Timeout information:
--- Timeout information end.
elapsed time (seconds): 507.935
----------configuration:(3/49)----------
Boot Layer
  add modules: jdk.incubator.foreign

----------System.out:(641/79463)----------
[TestNG] Running:
  java/foreign/TestMismatch.java

test TestMismatch.testClosed(): success
testDifferentValues s1:MemorySegment{ id=0x2d6b6ce1 limit: 16 }, s2:MemorySegment{ id=0x2d6d7801 limit: 16 }
test TestMismatch.testDifferentValues(jdk.internal.foreign.NativeMemorySegmentImpl@6dac95ed, jdk.internal.foreign.NativeMemorySegmentImpl@6c7a1b3c): success
testDifferentValues s1:MemorySegment{ id=0x2d6b6ce1 limit: 16 }, s2:MemorySegment{ id=0x2d6d7801 limit: 8 }
test TestMismatch.testDifferentValues(jdk.internal.foreign.NativeMemorySegmentImpl@6dac95ed, jdk.internal.foreign.NativeMemorySegmentImpl@104d4138): success

<snip>

testSameValues s1:MemorySegment{ id=0x242e7e1c limit: 1 }, s2:MemorySegment{ id=0x6815dc7 limit: 1 }
test TestMismatch.testSameValues(jdk.internal.foreign.HeapMemorySegmentImpl@28c6d674, jdk.internal.foreign.HeapMemorySegmentImpl@69a69aec): success
test TestMismatch.testThreadAccess(): success

===============================================
java/foreign/TestMismatch.java
Total tests run: 2894, Failures: 0, Skips: 0
===============================================

----------System.err:(2/71)----------
WARNING: Using incubator modules: jdk.incubator.foreign
STATUS:Passed.
----------rerun:(38/5497)*----------

The test timed out, but PASSed during JTREG timeout handler
execution:

elapsed time (seconds): 507.935
STATUS:Passed.

The test in using the default timeout value of 120 seconds/2 minutes
and with the default timeoutFactor of 4 that gives us 180 seconds.
For some reason this test execution took ~508 seconds.

The average test execution time should be examined. Perhaps the
test needs a slightly longer timeout value, e.g., 180 seconds for a
total timeout value of 720 seconds/12 minutes.

Or it's possible that there was a load issue on the test machine.

I've never heard of java/foreign before so I'm starting this bug
off in core-libs.