Integrated: 8290909: MemoryPoolMBean/isUsageThresholdExceeded tests failed with "isUsageThresholdExceeded() returned false, and is still false, while threshold = MMMMMMM and used peak = NNNNNNN"

[Kevin Walls]

On Thu, 11 Aug 2022 18:27:12 GMT, Kevin Walls <kevinw at openjdk.org> wrote:

> This is test unstable when monitoring CodeHeap pools as they can change outside the test's control.
> Attempting more heuristics to sense these unrelated changes just means we skip more pools.
> 
> The test design, making a Java allocation to affect a memory pool, shows it was intended for Java heap pools, so the test should focus on them.  If we make a larger allocation during the test we actually can observe a change in size in the old gen pools it monitors (new gen pools are not expected to have thresholds, so they are skipped).
> 
> There exist specific tests in test/hotspot/jtreg/compiler/codecache/jmx which are intended for non-heap pools, so we should skip them intentionally here in isUsageThresholdExceeded.
> 
> Other edits in the test to fix that the peak usage reported by the test was simply usage, not peak.  Fetch the usage and peak usage as near together as possible in the test.  At line 110 in the test, remove an attempt to skip pools we can't monitor (which was working, but does not cover all cases).
> 
> 
> Example test log, showing allocation that hits the old gen and triggers the threshold set by the test:
> 
> ----------System.out:(15/796)----------
> ...
> 5 pool G1 Old Gen of type: Heap memory
>      used value is 1024000      max is 1038090240 isExceeded = false
> peak used value is 1024000
>   threshold set to 1024001
>   threshold count  0
>   reset peak usage. peak usage = 1024000 isExceeded = false
>   Allocated heap.  isExceeded = true
>      used value is 106930176      max is 1038090240 isExceeded = true
> peak used value is 106930176 peak max is 1038090240
>   threshold count  1

This pull request has now been integrated.

Changeset: 3601e30d
Author:    Kevin Walls <kevinw at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/3601e30df794db122d8d04fb3c04868ccbaa0baf
Stats:     19 lines in 1 file changed: 4 ins; 8 del; 7 mod

8290909: MemoryPoolMBean/isUsageThresholdExceeded tests failed with "isUsageThresholdExceeded() returned false, and is still false, while threshold = MMMMMMM and used peak = NNNNNNN"

Reviewed-by: cjplummer, amenkov

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PR: https://git.openjdk.org/jdk/pull/9842