re-number thread id in trace
This is to make trace viewable in https://ui.perfetto.dev/.
Bug: b/227130231
Change-Id: Ib979e6821b5c68f419dbd0b6b757f3ff0a945b06
Reviewed-on: https://gn-review.googlesource.com/c/gn/+/13323
Reviewed-by: Brett Wilson <brettw@chromium.org>
Commit-Queue: Brett Wilson <brettw@chromium.org>
diff --git a/src/gn/trace.cc b/src/gn/trace.cc
index f812710..bc3f50e 100644
--- a/src/gn/trace.cc
+++ b/src/gn/trace.cc
@@ -250,19 +250,27 @@
std::string quote_buffer; // Allocate outside loop to prevent reallocationg.
+ // Trace viewer doesn't handle integer > 2^53 well, so re-numbering them to
+ // small numbers.
+ std::map<std::thread::id, int> tidmap;
+ std::vector<TraceItem*> events = trace_log->events();
+ for (const auto* item : events) {
+ int id = tidmap.size();
+ tidmap.emplace(item->thread_id(), id);
+ }
+
// Write main thread metadata (assume this is being written on the main
// thread).
- out << "{\"pid\":0,\"tid\":\"" << std::this_thread::get_id() << "\"";
+ out << "{\"pid\":0,\"tid\":\"" << tidmap[std::this_thread::get_id()] << "\"";
out << ",\"ts\":0,\"ph\":\"M\",";
out << "\"name\":\"thread_name\",\"args\":{\"name\":\"Main thread\"}},";
- std::vector<TraceItem*> events = trace_log->events();
for (size_t i = 0; i < events.size(); i++) {
const TraceItem& item = *events[i];
if (i != 0)
out << ",";
- out << "{\"pid\":0,\"tid\":\"" << item.thread_id() << "\"";
+ out << "{\"pid\":0,\"tid\":\"" << tidmap[item.thread_id()] << "\"";
out << ",\"ts\":" << item.begin() / kNanosecondsToMicroseconds;
out << ",\"ph\":\"X\""; // "X" = complete event with begin & duration.
out << ",\"dur\":" << item.delta().InMicroseconds();
