Reviewers: alph, loislo,
Description:
Save heap object tracking data in heap snapshot
Every time embedder calls v8::HeapProfiler::GetHeapStats we store next
unuassigned heap object id and timestamp of the request. This patch
serializes
all that data into heap snapshot so that embedder can restore allocation
timeline.
BUG=chromium:467222
LOG=Y
Please review this at https://codereview.chromium.org/1019813004/
Base URL: https://chromium.googlesource.com/v8/v8.git@master
Affected files (+56, -7 lines):
M src/heap-snapshot-generator.h
M src/heap-snapshot-generator.cc
Index: src/heap-snapshot-generator.cc
diff --git a/src/heap-snapshot-generator.cc b/src/heap-snapshot-generator.cc
index
5864ad9b43fb9e82cf55b8e35a0bd0a3749d3ee7..ce9d705cd5e5730a2424a5ac87963474bd623191
100644
--- a/src/heap-snapshot-generator.cc
+++ b/src/heap-snapshot-generator.cc
@@ -2743,6 +2743,11 @@ void HeapSnapshotJSONSerializer::SerializeImpl() {
if (writer_->aborted()) return;
writer_->AddString("],\n");
+ writer_->AddString("\"samples\":[");
+ SerializeSamples();
+ if (writer_->aborted()) return;
+ writer_->AddString("],\n");
+
writer_->AddString("\"strings\":[");
SerializeStrings();
if (writer_->aborted()) return;
@@ -2939,7 +2944,10 @@ void HeapSnapshotJSONSerializer::SerializeSnapshot()
{
JSON_S("function_info_index") ","
JSON_S("count") ","
JSON_S("size") ","
- JSON_S("children"))));
+ JSON_S("children")) ","
+ JSON_S("sample_fields") ":" JSON_A(
+ JSON_S("timstamp_ms") ","
+ JSON_S("next_object_id"))));
#undef JSON_S
#undef JSON_O
#undef JSON_A
@@ -2954,6 +2962,10 @@ void HeapSnapshotJSONSerializer::SerializeSnapshot()
{
count = tracker->function_info_list().length();
}
writer_->AddNumber(count);
+ writer_->AddString(",\"sample_count\":");
+ const List<HeapObjectsMap::TimeInterval>& samples =
+ snapshot_->profiler()->heap_object_map()->samples();
+ writer_->AddNumber(samples.length());
}
@@ -3057,6 +3069,38 @@ void
HeapSnapshotJSONSerializer::SerializeTraceNodeInfos() {
}
+void HeapSnapshotJSONSerializer::SerializeSamples() {
+ const List<HeapObjectsMap::TimeInterval>& samples =
+ snapshot_->profiler()->heap_object_map()->samples();
+ if (samples.is_empty()) return;
+ base::TimeTicks start_time = samples[0].timestamp;
+ // The buffer needs space for 2 unsigned ints, 2 commas, \n and \0
+ const int kBufferSize =
+ 2 * MaxDecimalDigitsIn<sizeof(
+ base::TimeDelta().InMilliseconds())>::kUnsigned // NOLINT
+ +
+ 2 + 1 + 1;
+ EmbeddedVector<char, kBufferSize> buffer;
+ bool first_entry = true;
+ for (int i = 0; i < samples.length(); i++) {
+ HeapObjectsMap::TimeInterval& sample = samples[i];
+ int buffer_pos = 0;
+ if (first_entry) {
+ first_entry = false;
+ } else {
+ buffer[buffer_pos++] = ',';
+ }
+ base::TimeDelta time_delta = sample.timestamp - start_time;
+ buffer_pos = utoa(time_delta.InMilliseconds(), buffer, buffer_pos);
+ buffer[buffer_pos++] = ',';
+ buffer_pos = utoa(sample.id, buffer, buffer_pos);
+ buffer[buffer_pos++] = '\n';
+ buffer[buffer_pos++] = '\0';
+ writer_->AddString(buffer.start());
+ }
+}
+
+
void HeapSnapshotJSONSerializer::SerializeString(const unsigned char* s) {
writer_->AddCharacter('\n');
writer_->AddCharacter('\"');
Index: src/heap-snapshot-generator.h
diff --git a/src/heap-snapshot-generator.h b/src/heap-snapshot-generator.h
index
55d36ce946af66d4a1f6d9c94c2e72b0d724ac5a..6bb549ae8b39561245156e3ed23be1de5cce80bd
100644
--- a/src/heap-snapshot-generator.h
+++ b/src/heap-snapshot-generator.h
@@ -194,6 +194,15 @@ class HeapSnapshot {
class HeapObjectsMap {
public:
+ struct TimeInterval {
+ explicit TimeInterval(SnapshotObjectId id)
+ : id(id), size(0), count(0), timestamp(base::TimeTicks::Now()) {}
+ SnapshotObjectId id;
+ uint32_t size;
+ uint32_t count;
+ base::TimeTicks timestamp;
+ };
+
explicit HeapObjectsMap(Heap* heap);
Heap* heap() const { return heap_; }
@@ -210,6 +219,7 @@ class HeapObjectsMap {
void StopHeapObjectsTracking();
SnapshotObjectId PushHeapObjectsStats(OutputStream* stream);
+ const List<TimeInterval>& samples() const { return time_intervals_; }
size_t GetUsedMemorySize() const;
SnapshotObjectId GenerateId(v8::RetainedObjectInfo* info);
@@ -236,12 +246,6 @@ class HeapObjectsMap {
unsigned int size;
bool accessed;
};
- struct TimeInterval {
- explicit TimeInterval(SnapshotObjectId id) : id(id), size(0), count(0)
{ }
- SnapshotObjectId id;
- uint32_t size;
- uint32_t count;
- };
SnapshotObjectId next_id_;
HashMap entries_map_;
@@ -584,6 +588,7 @@ class HeapSnapshotJSONSerializer {
void SerializeTraceTree();
void SerializeTraceNode(AllocationTraceNode* node);
void SerializeTraceNodeInfos();
+ void SerializeSamples();
void SerializeString(const unsigned char* s);
void SerializeStrings();
--
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