RFR: 8267246: -XX:MaxRAMPercentage=0 is unreasonable for jtreg tests on many-core machines

[Jie Fu]

On Mon, 17 May 2021 13:24:16 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 `MaxRAMPercentage` will be always 0 if JTREG_JOBS > 25 [1].
> 
> It can be reproduced by: `make test TEST="vmTestbase/vm/mlvm/anonloader/stress/oome/metaspace/Test.java" JTREG="JOBS=26"` on almost all machines.
> 
> Setting `-XX:MaxRAMPercentage=0` on many-core machines seems unreasonable.
> It would be better to fix it.
> 
> Thanks.
> Best regards,
> Jie
> 
> 
> [1] https://github.com/openjdk/jdk/blob/master/make/RunTests.gmk#L741

> _Mailing list message from [Aleksey Shipilev](mailto:shade at redhat.com) on [build-dev](mailto:build-dev at mail.openjdk.java.net):_
> 
> On 5/17/21 7:30 PM, erik.joelsson at oracle.com wrote:
> 
> > Oh, if it's double, we can just switch to using awk to make the
> > calculation, just like we do for TEST_JOBS. I just did a quick check and
> > it produces float values.
> 
> Oh, cool. Having a more precise MaxRAMPercentage would be nice.
> 
> --
> Thanks,
> -Aleksey

Hi @erikj79 and @shipilev ,

Patch has been updated to using awk to make the calculation.
Thanks.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4062