Request for Review (s) - 8133023: ParallelGCThreads is not calculated correctly

[Kim Barrett]

On Nov 25, 2015, at 9:11 PM, David Holmes <david.holmes at oracle.com> wrote:
> 
> We already have VM_Version::early_initialize() that can/should be used for this if possible.

VM_Version::early_initialize doesn’t work for this, because
determine_features (sparc) examines some command-line arguments, and
those aren't parsed until a later stage of Threads::create_vm.

Specifically, determine_features (sparc) is presently looking at two
CLAs: UseV8InstrsOnly (develop) and UseNiagaraInstrs (product).  I
suspect UseV8InstrsOnly has served its purpose and could be purged.
But calling determine_features before argument parsing would
unintentionally ignore UseNiagaraInstrs.

Calling determine_features from os::init_before_ergo doesn't have this problem.

[I missed this in my review of Jon’s original change to use early_initialize.]