RFR: 8267246: -XX:MaxRAMPercentage=0 is unreasonable for jtreg tests on many-core machines [v2]

[Jie Fu]

> 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

Jie Fu has updated the pull request incrementally with one additional commit since the last revision:

  Use awk to compute MaxRAMPercentage

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/4062/files
  - new: https://git.openjdk.java.net/jdk/pull/4062/files/94aac13b..a1e7aea9

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=4062&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=4062&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/4062.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/4062/head:pull/4062

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