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[ Profiler ] Fix CPU sample streaming sending only a single sample block instead of a chain of blocks

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A pointer to a single SampleBlockBuffer was being passed in while
building a profile instead of a reference to SampleBlockListProcessor.
This also could lead to a segfault if there were no blocks to process.

TEST=CQ + manual testing in Flutter engine

Change-Id: I1e2903cf718da7b32747553c2ed1efcb78b62c86
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/214441
Commit-Queue: Ben Konyi <bkonyi@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>
This commit is contained in:
Ben Konyi 2021-09-24 23:02:49 +00:00 committed by commit-bot@chromium.org
parent 70533ae7fa
commit 7786183e14
1 changed files with 9 additions and 5 deletions
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14
runtime/vm/isolate.cc
View file

@ -2384,10 +2384,14 @@ void Isolate::FreeSampleBlock(SampleBlock* block) {
void Isolate::ProcessFreeSampleBlocks(Thread* thread) {
SampleBlock* head = free_block_list_.exchange(nullptr);
if (head == nullptr) {
// No sample blocks to process.
return;
}
// Reverse the list before processing so older blocks are streamed and reused
// first.
SampleBlock* reversed_head = nullptr;
while (head != nullptr) {
do {
SampleBlock* next = head->next_free_;
if (reversed_head == nullptr) {
reversed_head = head;
@ -2397,7 +2401,7 @@ void Isolate::ProcessFreeSampleBlocks(Thread* thread) {
reversed_head = head;
}
head = next;
}
} while (head != nullptr);
head = reversed_head;
if (Service::profiler_stream.enabled() && !IsSystemIsolate(this)) {
@ -2405,20 +2409,20 @@ void Isolate::ProcessFreeSampleBlocks(Thread* thread) {
StackZone zone(thread);
HandleScope handle_scope(thread);
Profile profile;
profile.Build(thread, nullptr, head);
profile.Build(thread, nullptr, &buffer);
ServiceEvent event(this, ServiceEvent::kCpuSamples);
event.set_cpu_profile(&profile);
Service::HandleEvent(&event);
}
while (head != nullptr) {
do {
SampleBlock* next = head->next_free_;
head->next_free_ = nullptr;
head->evictable_ = true;
Profiler::sample_block_buffer()->FreeBlock(head);
head = next;
thread->CheckForSafepoint();
}
} while (head != nullptr);
}
#endif // !defined(PRODUCT)