8346875: Test jdk/jdk/jfr/event/os/TestCPULoad.java fails on macOS

[MBaesken]

The test fails on some new Mac instances (macOS 14.5 (macOS aarch64) , CPU Apple M2) with :
java.lang.AssertionError: Expected at least one event
at jdk.jfr.event.os.TestCPULoad.main(TestCPULoad.java:62)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1447)

The current sleep value seems to be a bit too slow for those machines. The issues occured (mostly) with fastdebug binaries.

---

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Issue

• JDK-8346875: Test jdk/jdk/jfr/event/os/TestCPULoad.java fails on macOS (Bug - P4)

Reviewers

• Erik Gahlin (@egahlin - Reviewer)

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[bridgekeeper]

👋 Welcome back mbaesken! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@MBaesken This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8346875: Test jdk/jdk/jfr/event/os/TestCPULoad.java fails on macOS

Reviewed-by: egahlin

You can use pull request commands such as /summary, /contributor and /issue to adjust it as needed.

At the time when this comment was updated there had been 23 new commits pushed to the master branch:

• 07a0dcb: 8347576: Error output in libjsound has non matching format strings
• d218b54: 8347609: Replace SIZE_FORMAT in os/os_cpu/cpu directories
• e7795cc: 8347347: Build fails undefined symbol: __asan_init by clang17
• 788f049: 8346607: IGV: Support drag-and-drop for opening graph files
• bfa0cb7: 8347730: Replace SIZE_FORMAT in g1
• 3b6e576: 8347825: Make IDEA ide support use proper build system mechanisms
• 8bfa540: 8347731: Replace SIZE_FORMAT in zgc
• cbe2f96: 8347732: Replace SIZE_FORMAT in shenandoah
• f64f22b: 8346107: Generators: testing utility for random value generation
• 4ad5d55: 8325030: PhaseMacroExpand::value_from_mem_phi assert with "unknown node on this path"
• ... and 13 more: https://git.openjdk.org/jdk/compare/7df21a8f09ab606f38a44d84d841d4bba9f09adf...master

As there are no conflicts, your changes will automatically be rebased on top of these commits when integrating. If you prefer to avoid this automatic rebasing, please check the documentation for the /integrate command for further details.

➡️ To integrate this PR with the above commit message to the master branch, type /integrate in a new comment.

[openjdk]

@MBaesken The following label will be automatically applied to this pull request:

• hotspot-jfr

When this pull request is ready to be reviewed, an "RFR" email will be sent to the corresponding mailing list. If you would like to change these labels, use the /label pull request command.

[mlbridge]

Webrevs

• 01: Full - Incremental (382a12f6)
• 00: Full (ad334587)

[egahlin]

Do you think it is this line that prevents us from getting a sample.

jdk/src/hotspot/os/bsd/os_perf_bsd.cpp

Line 140 in 9c430c9

if (total_delta == 0) {

Maybe we should do some work instead of additional sleeping?

[MBaesken]

Not sure if it is this line. Should we maybe add some UL tracing; enable it for the test and see if we hit this ?

Maybe we should do some work instead of additional sleeping?

Could be that this helps; or increase the sleep time (but less than I did) AND do some CPU intensive work .

[egahlin]

Could be that this helps; or increase the sleep time (but less than I did) AND do some CPU intensive work .

You could keep the 100 ms and do some CPU intensive work. If it still fails, then we'll know it's not CPU work related. If we change both at once, it's harder to analyze.

If I remember correctly, we didn't have sleep at all initially (2012). Then we had a smaller sleep which was later increased to 100 ms. We should probably have tried to add CPU related work instead of increasing the sleep time.

[MBaesken]

Hi Erik, I added some code doing a few calculations. Let's see if this is good .

[egahlin]

I tried running the test 100 times on different operating systems and hardware. No failures. Let's try this.

[MBaesken]

Hi Erik, thanks for the review ! Let's see if this is better than the sleep (or maybe we need both, sleep and cycle burning) .

/integrate

[openjdk]

Going to push as commit a3eef6c.
Since your change was applied there have been 27 commits pushed to the master branch:

• 398a580: 8347911: Limit the length of inflated text chunks
• aa21de5: 8347481: C2: Remove the control input of some nodes
• 1f365cc: 8346433: Cannot use DllMain in hotspot for static builds
• 0330ca4: 8347617: Shenandoah: Use consistent name for update references phase
• 07a0dcb: 8347576: Error output in libjsound has non matching format strings
• d218b54: 8347609: Replace SIZE_FORMAT in os/os_cpu/cpu directories
• e7795cc: 8347347: Build fails undefined symbol: __asan_init by clang17
• 788f049: 8346607: IGV: Support drag-and-drop for opening graph files
• bfa0cb7: 8347730: Replace SIZE_FORMAT in g1
• 3b6e576: 8347825: Make IDEA ide support use proper build system mechanisms
• ... and 17 more: https://git.openjdk.org/jdk/compare/7df21a8f09ab606f38a44d84d841d4bba9f09adf...master

Your commit was automatically rebased without conflicts.

[openjdk]

@MBaesken Pushed as commit a3eef6c.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

[MBaesken]

Hi Erik @egahlin , we unfortunately still sometimes see the error after this change

----------System.out:(1/41)----------
Found 183072 primes while burning cycles
----------System.err:(11/642)----------
java.lang.AssertionError: Expected at least one event
at jdk.jfr.event.os.TestCPULoad.main(TestCPULoad.java:80)
at java.base/jdk.internal.reflect.DirectMethodHandleAccessor.invoke(DirectMethodHandleAccessor.java:104)
at java.base/java.lang.reflect.Method.invoke(Method.java:565)
at com.sun.javatest.regtest.agent.MainWrapper$MainTask.run(MainWrapper.java:138)
at java.base/java.lang.Thread.run(Thread.java:1447)

So burning cycles did not really help .

[egahlin]

Hi Erik @egahlin , we unfortunately still sometimes see the error after this change

I've noticed the same thing when running them in parallel, i.e.,

$ jtreg -conc:32 -v:a -jdk ... test/jdk/jdk/jfr 

You could try adding logging (log_debug(jfr, system)("...")) and see if you can reproduce the issue. If it's not a product bug, you could try to use an event stream instead.

public static void main(String... args) throws Exception {
  List<RecordedEvent> events = new ArrayList<>();
  try (var rs = new RecordingStream()) {
    rs.setReuse(false);
    rs.enable("jdk.CPULoad").withPeriod(Duration.ofMillis(50));
    rs.onEvent(e -> {
      events.add(e);
      rs.close();
    });
    rs.start();
    verifyEvent(events.getFirst());
  }
}

private static void verifyEvent(RecordedEvent e) throws Exception {
  ...
}`