commit 8c96812bec49947e2e70c788568fac9e36d33814
author Ryan Macnak <rmacnak@google.com> Mon Apr 27 23:42:36 2020 +0000
committer commit-bot@chromium.org <commit-bot@chromium.org> Mon Apr 27 23:42:36 2020 +0000
tree 1bd95f99e887e37e3ee2ebaf7d73331beb0e12af
parent f3751ae846a0087a385659b83073083fe6370197

[vm, timeline] Remember block creation order instead of sorting in the endless recorder.

Reduces time, and more importantly auxiliary memory, to retrieve the timeline.

Change-Id: I0f87797f6d851d00cc5df0abaf5274693cb95752
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/144810
Reviewed-by: Alexander Aprelev <aam@google.com>
Reviewed-by: Ben Konyi <bkonyi@google.com>
Commit-Queue: Ryan Macnak <rmacnak@google.com>

runtime/vm/timeline.cc

diff --git a/runtime/vm/timeline.cc b/runtime/vm/timeline.cc
index 48d4884..afbd027 100644
--- a/runtime/vm/timeline.cc
+++ b/runtime/vm/timeline.cc
@@ -1321,13 +1321,13 @@
 }
 
 TimelineEventEndlessRecorder::TimelineEventEndlessRecorder()
-    : head_(NULL), block_index_(0) {}
+    : head_(nullptr), tail_(nullptr), block_index_(0) {}
 
 TimelineEventEndlessRecorder::~TimelineEventEndlessRecorder() {
   TimelineEventBlock* current = head_;
-  head_ = NULL;
+  head_ = tail_ = nullptr;
 
-  while (current != NULL) {
+  while (current != nullptr) {
     TimelineEventBlock* next = current->next();
     delete current;
     current = next;
@@ -1374,45 +1374,30 @@
 
 TimelineEventBlock* TimelineEventEndlessRecorder::GetNewBlockLocked() {
   TimelineEventBlock* block = new TimelineEventBlock(block_index_++);
-  block->set_next(head_);
   block->Open();
-  head_ = block;
+  if (head_ == nullptr) {
+    head_ = tail_ = block;
+  } else {
+    tail_->set_next(block);
+    tail_ = block;
+  }
   if (FLAG_trace_timeline) {
     OS::PrintErr("Created new block %p\n", block);
   }
-  return head_;
+  return block;
 }
 
 #ifndef PRODUCT
-static int TimelineEventBlockCompare(TimelineEventBlock* const* a,
-                                     TimelineEventBlock* const* b) {
-  return (*a)->LowerTimeBound() - (*b)->LowerTimeBound();
-}
-
 void TimelineEventEndlessRecorder::PrintJSONEvents(
     JSONArray* events,
     TimelineEventFilter* filter) {
   MutexLocker ml(&lock_);
   ResetTimeTracking();
-  // Collect all interesting blocks.
-  MallocGrowableArray<TimelineEventBlock*> blocks(8);
-  TimelineEventBlock* current = head_;
-  while (current != NULL) {
-    if (filter->IncludeBlock(current)) {
-      blocks.Add(current);
+  for (TimelineEventBlock* current = head_; current != nullptr;
+       current = current->next()) {
+    if (!filter->IncludeBlock(current)) {
+      continue;
     }
-    current = current->next();
-  }
-  // Bail early.
-  if (blocks.length() == 0) {
-    return;
-  }
-  // Sort the interesting blocks so that blocks with earlier events are
-  // outputted first.
-  blocks.Sort(TimelineEventBlockCompare);
-  // Output blocks in sorted order.
-  for (intptr_t block_idx = 0; block_idx < blocks.length(); block_idx++) {
-    current = blocks[block_idx];
     intptr_t length = current->length();
     for (intptr_t i = 0; i < length; i++) {
       TimelineEvent* event = current->At(i);

runtime/vm/timeline.h

diff --git a/runtime/vm/timeline.h b/runtime/vm/timeline.h
index e45b144..8841258 100644
--- a/runtime/vm/timeline.h
+++ b/runtime/vm/timeline.h
@@ -866,6 +866,7 @@
 #endif
 
   TimelineEventBlock* head_;
+  TimelineEventBlock* tail_;
   intptr_t block_index_;
 
   friend class TimelineTestHelper;