Disable read barriers in GC VisitReferences calls.
It's safe to disable read barriers in the CC collector's
VisitReferences calls. It speeds up the collector by some amount,
eg. Ritzperf EAAC GC time on N5 decreases by ~4.2%.
This is based on Mathieu Chartier's idea.
Bug: 12687968
Change-Id: I884dee7018f92761fad54269f4cd01db4fa82f2a
diff --git a/runtime/gc/collector/concurrent_copying.cc b/runtime/gc/collector/concurrent_copying.cc
index 8e1b7f4..d393f0b 100644
--- a/runtime/gc/collector/concurrent_copying.cc
+++ b/runtime/gc/collector/concurrent_copying.cc
@@ -1622,7 +1622,9 @@
inline void ConcurrentCopying::Scan(mirror::Object* to_ref) {
DCHECK(!region_space_->IsInFromSpace(to_ref));
ConcurrentCopyingRefFieldsVisitor visitor(this);
- to_ref->VisitReferences(visitor, visitor);
+ // Disable the read barrier for a performance reason.
+ to_ref->VisitReferences</*kVisitNativeRoots*/true, kDefaultVerifyFlags, kWithoutReadBarrier>(
+ visitor, visitor);
}
// Process a field.
diff --git a/runtime/mirror/class-inl.h b/runtime/mirror/class-inl.h
index 422832e..3f806d3 100644
--- a/runtime/mirror/class-inl.h
+++ b/runtime/mirror/class-inl.h
@@ -532,8 +532,9 @@
return GetFieldPtr<LengthPrefixedArray<ArtField>*>(OFFSET_OF_OBJECT_MEMBER(Class, ifields_));
}
+template<VerifyObjectFlags kVerifyFlags, ReadBarrierOption kReadBarrierOption>
inline MemberOffset Class::GetFirstReferenceInstanceFieldOffset() {
- Class* super_class = GetSuperClass();
+ Class* super_class = GetSuperClass<kVerifyFlags, kReadBarrierOption>();
return (super_class != nullptr)
? MemberOffset(RoundUp(super_class->GetObjectSize(),
sizeof(mirror::HeapReference<mirror::Object>)))
diff --git a/runtime/mirror/class.h b/runtime/mirror/class.h
index 388a231..37a77a7 100644
--- a/runtime/mirror/class.h
+++ b/runtime/mirror/class.h
@@ -1006,6 +1006,8 @@
SHARED_REQUIRES(Locks::mutator_lock_);
// Get the offset of the first reference instance field. Other reference instance fields follow.
+ template<VerifyObjectFlags kVerifyFlags = kDefaultVerifyFlags,
+ ReadBarrierOption kReadBarrierOption = kWithReadBarrier>
MemberOffset GetFirstReferenceInstanceFieldOffset()
SHARED_REQUIRES(Locks::mutator_lock_);
diff --git a/runtime/mirror/object-inl.h b/runtime/mirror/object-inl.h
index eb391be..76a36ac 100644
--- a/runtime/mirror/object-inl.h
+++ b/runtime/mirror/object-inl.h
@@ -1068,7 +1068,7 @@
MemberOffset field_offset = kIsStatic
? klass->GetFirstReferenceStaticFieldOffset<kVerifyFlags, kReadBarrierOption>(
Runtime::Current()->GetClassLinker()->GetImagePointerSize())
- : klass->GetFirstReferenceInstanceFieldOffset();
+ : klass->GetFirstReferenceInstanceFieldOffset<kVerifyFlags, kReadBarrierOption>();
for (size_t i = 0u; i < num_reference_fields; ++i) {
// TODO: Do a simpler check?
if (field_offset.Uint32Value() != ClassOffset().Uint32Value()) {