RFR(trivial): 8213695: gc/TestAllocateHeapAtMultiple.java is slow in some configs

[Kharbas, Kishor]

Greetings,

I ran this test multiple times on Linux & Windows and the tests complete in less than a second. However, I do not have a sparc system to test (if I am correct, earlier discussion pointed that timeout issue is seen on sparc).

My guess of what is happening is - For testing purposes we use the file system of the test directory, instead of a dax filesystem for nv-dimm. With the AllocateHeapAt flag set, heap memory is mapped to a temporary file in the test directory. Depending on the test environment (filesystem, memory, disk, etc), heap memory access might be quite slower.

So I think we should decrease the heap size of the tests. The 5th & 6th subtests can be changed to use 32M instead of 4G. The 4th subtest can be removed.

Here is the patch with the changes - http://cr.openjdk.java.net/~kkharbas/8213695/webrev.00/
Hopefully someone can test whether this change makes the run time deterministic.

Thanks,
Kishor