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tracing: Fix some race conditions#22812

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ofrobots wants to merge 2 commits into from
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tracing: Fix some race conditions #22812

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4d352f6
deps: cherry-pick 2363cdf from upstream V8
ofrobots Sep 11, 2018
ac56580
tracing: avoid flusing uninitialized traces
ofrobots Sep 12, 2018
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2 changes: 1 addition & 1 deletion common.gypi
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Original file line numberDiff line numberDiff line change
Expand Up@@ -29,7 +29,7 @@

# Reset this number to 0 on major V8 upgrades.
# Increment by one for each non-official patch applied to deps/v8.
'v8_embedder_string': '-node.9',
'v8_embedder_string': '-node.10',

# Enable disassembler for `--print-code` v8 options
'v8_enable_disassembler': 1,
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32 changes: 18 additions & 14 deletions deps/v8/src/libplatform/tracing/tracing-controller.cc
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Expand Up@@ -63,13 +63,15 @@ uint64_t TracingController::AddTraceEvent(
const uint64_t* arg_values,
std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
unsigned int flags) {
uint64_t handle;
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(
phase, category_enabled_flag, name, scope, id, bind_id, num_args,
arg_names, arg_types, arg_values, arg_convertables, flags,
CurrentTimestampMicroseconds(), CurrentCpuTimestampMicroseconds());
uint64_t handle = 0;
if (mode_ != DISABLED) {
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(
phase, category_enabled_flag, name, scope, id, bind_id, num_args,
arg_names, arg_types, arg_values, arg_convertables, flags,
CurrentTimestampMicroseconds(), CurrentCpuTimestampMicroseconds());
}
}
return handle;
}
Expand All@@ -81,13 +83,15 @@ uint64_t TracingController::AddTraceEventWithTimestamp(
const uint64_t* arg_values,
std::unique_ptr<v8::ConvertableToTraceFormat>* arg_convertables,
unsigned int flags, int64_t timestamp) {
uint64_t handle;
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(phase, category_enabled_flag, name, scope, id,
bind_id, num_args, arg_names, arg_types,
arg_values, arg_convertables, flags, timestamp,
CurrentCpuTimestampMicroseconds());
uint64_t handle = 0;
if (mode_ != DISABLED) {
TraceObject* trace_object = trace_buffer_->AddTraceEvent(&handle);
if (trace_object) {
trace_object->Initialize(phase, category_enabled_flag, name, scope, id,
bind_id, num_args, arg_names, arg_types,
arg_values, arg_convertables, flags, timestamp,
CurrentCpuTimestampMicroseconds());
}
}
return handle;
}
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8 changes: 7 additions & 1 deletion src/tracing/node_trace_buffer.cc
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Expand Up@@ -59,7 +59,13 @@ void InternalTraceBuffer::Flush(bool blocking) {
for (size_t i = 0; i < total_chunks_; ++i) {
auto& chunk = chunks_[i];
for (size_t j = 0; j < chunk->size(); ++j) {
agent_->AppendTraceEvent(chunk->GetEventAt(j));
TraceObject* trace_event = chunk->GetEventAt(j);

@refackrefackSep 12, 2018

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Why not auto?

@addaleaxaddaleaxSep 12, 2018•
edited
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We tend to avoid auto, except for cases where the type is hard to spell out (e.g. STL iterator types/dependent on templating), or long and easy to infer (e.g. auto foo = new VeryLongClassName();). Using auto means spending more time writing the code, but more time reading it, and Node.js code is typically read a lot more than it is written.

@refackrefackSep 14, 2018

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IMHO it's time for that to change (ES.11).
Beside using the CCG to not bikeshed, for me as a reader TraceObject* is as opaque as auto, that why we have IDEs.

// Another thread may have added a trace that is yet to be
// initialized. Skip such traces.
// https://github.com/nodejs/node/issues/21038.
if (trace_event->name()) {
agent_->AppendTraceEvent(trace_event);
}
}
}
total_chunks_ = 0;
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