RFR: 8267293: vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails when JTREG_JOBS > 25

[Thomas Stuefe]

On Mon, 17 May 2021 23:28:43 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> Hi all,
> 
> vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java fails on our many-core machines due to `-XX:MaxRAMPercentage=0`.
> This is because `-XX:MaxRAMPercentage=0` will be 0 if JTREG_JOBS > 25 [1].
> 
> We can also reproduce the bug by: `make test TEST="vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java" JTREG="JOBS=26"` on almost all machines.
> 
> This fix will make it to be more robust, which is suggested by  @shipilev [2] and many thanks to him.
> 
> Thanks.
> Best regards,
> Jie
> 
> [1] https://github.com/openjdk/jdk/blob/master/make/RunTests.gmk#L741
> [2] https://github.com/openjdk/jdk/pull/4062#pullrequestreview-661198240

Hi Jie,

You can safely get by with less. A very safe bet for all platforms would be:

- 256m heap
- 8m MaxMetaspaceSize

The latter could be probably reduced more (the smaller metaspace, the faster the test comes to conclusion), down to 6m or 4m. On my machine 4m works for both 64 and 32bit. But 8m is probably safe on all platforms.

Cheers, Thomas

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PR: https://git.openjdk.java.net/jdk/pull/4076