8185572: Enable AssumeMP by default on SPARC machines
Reviewed-by: kvn, dholmes, bobv
--- a/hotspot/src/share/vm/runtime/arguments.cpp Tue Aug 15 15:02:40 2017 +0300
+++ b/hotspot/src/share/vm/runtime/arguments.cpp Tue Aug 15 14:03:52 2017 +0000
@@ -4462,6 +4462,16 @@
set_shared_spaces_flags();
+#if defined(SPARC)
+ // BIS instructions require 'membar' instruction regardless of the number
+ // of CPUs because in virtualized/container environments which might use only 1
+ // CPU, BIS instructions may produce incorrect results.
+
+ if (FLAG_IS_DEFAULT(AssumeMP)) {
+ FLAG_SET_DEFAULT(AssumeMP, true);
+ }
+#endif
+
// Check the GC selections again.
if (!check_gc_consistency()) {
return JNI_EINVAL;