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[json] Remove pretenuring based on json source size

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It's not necessarily helpful, and can actually cause pretty bad performance and
memory usage.

I moved up the next_ field to where allocation_ used to be since apparently the
alignment caused by it has huge impact on perf (>10% diff...) at least on my
machine.

Change-Id: I1026a2e954d061b1a178f6a733d8ef81ae6d0cab
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1594432
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Reviewed-by: Igor Sheludko <ishell@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61250}
This commit is contained in:
Toon Verwaest 2019-05-06 17:36:16 +02:00 committed by Commit Bot
parent b3b6b5c655
commit 9b7347665e
2 changed files with 12 additions and 22 deletions
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23
src/json-parser.cc
View File

@ -262,10 +262,6 @@ JsonParser<Char>::JsonParser(Isolate* isolate, Handle<String> source)
}
cursor_ = chars_ + start;
end_ = cursor_ + length;
allocation_ = (source->length() >= kPretenureTreshold)
? AllocationType::kOld
: AllocationType::kYoung;
}
template <typename Char>
@ -453,8 +449,7 @@ bool JsonParser<Char>::ParseElement(Handle<JSObject> json_object) {
template <typename Char>
Handle<Object> JsonParser<Char>::ParseJsonObject() {
HandleScope scope(isolate());
Handle<JSObject> json_object =
factory()->NewJSObject(object_constructor(), allocation_);
Handle<JSObject> json_object = factory()->NewJSObject(object_constructor());
Handle<Map> map(json_object->map(), isolate());
int descriptor = 0;
VectorSegment<ZoneVector<Handle<Object>>> properties(&properties_);
@ -643,19 +638,18 @@ Handle<Object> JsonParser<Char>::ParseJsonArray() {
switch (kind) {
case PACKED_ELEMENTS:
case PACKED_SMI_ELEMENTS: {
Handle<FixedArray> elems =
factory()->NewFixedArray(elements_size, allocation_);
Handle<FixedArray> elems = factory()->NewFixedArray(elements_size);
for (int i = 0; i < elements_size; i++) elems->set(i, *elements[i]);
json_array = factory()->NewJSArrayWithElements(elems, kind, allocation_);
json_array = factory()->NewJSArrayWithElements(elems, kind);
break;
}
case PACKED_DOUBLE_ELEMENTS: {
Handle<FixedDoubleArray> elems = Handle<FixedDoubleArray>::cast(
factory()->NewFixedDoubleArray(elements_size, allocation_));
factory()->NewFixedDoubleArray(elements_size));
for (int i = 0; i < elements_size; i++) {
elems->set(i, elements[i]->Number());
}
json_array = factory()->NewJSArrayWithElements(elems, kind, allocation_);
json_array = factory()->NewJSArrayWithElements(elems, kind);
break;
}
default:
@ -757,7 +751,7 @@ Handle<Object> JsonParser<Char>::ParseJsonNumber(int sign, const Char* start) {
DCHECK(!std::isnan(number));
}
return factory()->NewNumber(number, allocation_);
return factory()->NewNumber(number);
}
namespace {
@ -810,12 +804,11 @@ Handle<String> JsonParser<Char>::MakeString(
chars.length() > kMaxInternalizedStringValueLength) {
if (sizeof(LiteralChar) == 1) {
return factory()
->NewStringFromOneByte(Vector<const uint8_t>::cast(chars),
allocation_)
->NewStringFromOneByte(Vector<const uint8_t>::cast(chars))
.ToHandleChecked();
}
return factory()
->NewStringFromTwoByte(Vector<const uint16_t>::cast(chars), allocation_)
->NewStringFromTwoByte(Vector<const uint16_t>::cast(chars))
.ToHandleChecked();
}

11
src/json-parser.h
View File

@ -167,7 +167,6 @@ class JsonParser final {
Handle<String> ParseJsonString(bool requires_internalization,
Handle<String> expected = Handle<String>());
Handle<String> ScanJsonString();
// A JSON number (production JSONNumber) is a subset of the valid JavaScript
// decimal number literals.
@ -212,7 +211,6 @@ class JsonParser final {
inline Handle<JSFunction> object_constructor() { return object_constructor_; }
static const int kInitialSpecialStringLength = 32;
static const int kPretenureTreshold = 100 * 1024;
static void UpdatePointersCallback(v8::Isolate* v8_isolate, v8::GCType type,
v8::GCCallbackFlags flags, void* parser) {
@ -252,7 +250,9 @@ class JsonParser final {
Isolate* isolate_;
Zone zone_;
const uint64_t hash_seed_;
AllocationType allocation_;
JsonToken next_;
// Indicates whether the bytes underneath source_ can relocate during GC.
bool chars_may_relocate_;
Handle<JSFunction> object_constructor_;
const Handle<String> original_source_;
Handle<String> source_;
@ -262,14 +262,11 @@ class JsonParser final {
// end_ should never be locally cached across a possible allocation. The scope
// in which we cache chars has to be guarded by a DisallowHeapAllocation
// scope.
const Char* chars_;
const Char* cursor_;
const Char* end_;
const Char* chars_;
JsonToken next_;
LiteralBuffer literal_buffer_;
// Indicates whether the bytes underneath source_ can relocate during GC.
bool chars_may_relocate_;
// Property handles are stored here inside ParseJsonObject.
ZoneVector<Handle<Object>> properties_;