jmx-dev RFR: 8351002: com/sun/management/OperatingSystemMXBean cpuLoad tests fail intermittently [v4]

[Serguei Spitsyn]

On Tue, 25 Mar 2025 21:46:26 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

>> These tests have always silently permitted a -1 return value from OperatingSystemMXBean CPU time methods.
>> 
>> They need to be stricter, but occasionally Windows 2019 returns a -1 for the first few calls of these methods.  This seems to be a Windows 2019 bug or peculiarity.  Other Windows versions are not affected.
>> 
>> GetProcessCpuLoad.java and GetSystemCpuLoad.java need to fail only if the CPU time calls continually return -1.  They should permit -1 values, as long as subsequently a value in the valid range is read.
>> 
>> The GetProcessCpuTime test also needs to retry enough times to expect no -1 values, and not just skip.  While updating this test: it has a maximum expected value of Long.MAX_VALUE, which it may as well reduce to something that does not look like a binary "all ones except for the high bit" value (without creating an ongoing game where we keep increasing the value to avoid failures in slow runs).
>
> Kevin Walls has updated the pull request incrementally with one additional commit since the last revision:
> 
>   stricter max time

The fix is a little bit hacky but as a work around should be okay.
LGTM

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Marked as reviewed by sspitsyn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24186#pullrequestreview-2715462558