RFR [XS]: 8239537: cgroup MetricsTester testMemorySubsystem fails sometimes when testing memory.kmem.tcp.usage_in_bytes

[mikhailo.seledtsov at oracle.com]

Looks good to me,

Misha

On 2/20/20 2:25 AM, Baesken, Matthias wrote:
> Hello, please review this small adjustment .
>
> The testMemorySubsystem test in MetricsTester.java sometimes fails with messages like this :
>
> java.lang.RuntimeException: Test failed for - memory:memory.kmem.tcp.usage_in_bytes, expected [655360], got [786432]
>                  at jdk.test.lib.containers.cgroup.MetricsTester.fail(MetricsTester.java:207)
>                  at jdk.test.lib.containers.cgroup.MetricsTester.testMemorySubsystem(MetricsTester.java:309)
>
> I looked into the  code doing the checks , and looks like there is already  an error margin allowed in CgroupMetricsTester.java , which is currently 0.1 .
> This might be changed to a somewhat higher value, e.g. 0.25 to make the test more robust.
>
>
> Bug/webrev :
>
> https://bugs.openjdk.java.net/browse/JDK-8239537
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8239537.0/
>
> Thanks, Matthias