RFR: 8153194: PreserveFPRegistersTest.java runs out of memory in the nightlies

[Vladimir Ivanov]

Thanks for taking care of the bug, Rahul.

> Please review the following test fix patch for JDK-8153194.
> <webrev.00> :  http://cr.openjdk.java.net/~rraghavan/8153194/webrev.00/

+ * @run main ClassFileInstaller sun.hotspot.WhiteBox
+ * @run main/othervm/timeout=300 -XX:+UnlockDiagnosticVMOptions
+ *      -XX:+WhiteBoxAPI -Xbatch -Xbootclasspath/a:.

You can use "@run main/bootclasspath/othervm" instead.


+        long regionSize = wb.g1RegionSize();

What happens if G1 isn't used? Either explicitly specify -XX:+UseG1GC or 
use @requires.

Otherwise, looks good.

Best regards,
Vladimir Ivanov

>
>
> Notes:
>
> https://bugs.openjdk.java.net/browse/JDK-8153194 - PreserveFPRegistersTest.java runs out of memory in the nightlies
> https://bugs.openjdk.java.net/browse/JDK-8148175 - C1: G1 barriers don't preserve FP registers
>
> - 'hotspot/test/compiler/gcbarriers/PreserveFPRegistersTest.java' was added as part of the old JDK-8148175 fix.
> - The 'PreserveFPRegistersTest.java' started failing in nightly tests for 64-bit targets only with -XX:-UseCompressedOops enabled.
> - Found wrong hard coded usage of reference size as 32 bits in test caused OutOfMemoryError, for -XX:-UseCompressedOops cases.
>
> Changes done -
> - Actual fix of setting reference size using WhiteBox.getHeapOopSize() and removed @ignore.
> - Used WhiteBox.g1RegionSize() instead of hard coded value.
> - Used -Xmx300m instead of -Xmx128m for run VM options.
>   (found this change is required for the test to fail correctly using old JDK9 builds prior to JDK-8148175 fix.
>    e.g.: for test to fail with "java.lang.AssertionError: Final value has changed: 0.0 != 6.0" using JDK9-b113.
>   Please note same -Xmx300m used for failing case reported in JDK-8148175.
> - Added diagnostic output.
>
> Testing done -
> - Confirmed revised test fails as expected using old jdk9 builds prior to JDK-8148175 fix (e.g.: JDK9-b113)
>    >> [Test finished: compiler/gcbarriers/PreserveFPRegistersTest.java: Failed. Execution failed: `main' threw exception: java.lang.AssertionError: Final value has changed: 0.0 != 6.0]
> (for default run and with -XX:-UseCompressedOops)
>
> -  Confirmed revised test is passing for latest source build (.i.e. with JDK-8148175 fix, starting from JDK9-b114)
> (with and without -XX:-UseCompressedOops)
>
>
> Thanks,
> Rahul
>