jmx-dev RFR: 8354407: Test com/sun/management/OperatingSystemMXBean/GetProcessCpuLoad.java still fails on Windows

[Kevin Walls]

On Wed, 30 Apr 2025 17:44:09 GMT, Chris Plummer <cjplummer at openjdk.org> wrote:

>> This is hard to reproduce, and at first I'd only seen -1 returned on the first calls to mbean.getProcessCpuLoad().
>> But eventually I observed a -1 at any time, including in middle of the iterations, or on the last iteration which makes the current test fail.
>> 
>> Should fail on Windows only if we only ever see -1 returned from getProcessCpuLoad().
>> Remove the "exclusiveAccess.dirs=." (JDK-8353231 adding "exclusiveAccess.dirs=." did not fix this.)
>
> test/jdk/com/sun/management/OperatingSystemMXBean/GetProcessCpuLoad.java line 60:
> 
>> 58:                 // A good reading: forget any previous -1.
>> 59:                 ex = null;
>> 60:                 good++;
> 
> The `ex = null` is a little misleading because actually it's irrelevant. An error on the next iteration will set it again, but it will be ignored because `good != 0`.

Yes, as long as there is a good value captured, Windows should pass.
We could get into how many good values we should see, I might suggest 6 out of 10? But that seems like a guessing game.
The breakage in this feature before meant it could never return a good value, that's what we need to guard against.

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PR Review Comment: https://git.openjdk.org/jdk/pull/24961#discussion_r2069241694