[ETW] Fix erased thread_ids (#1438)
Chrome ETW translator erases thread id for processes that aren't chrome,
for privacy/security concerns.
This updates trace processor to avoid interpreting this as idle, which
gets explicitly thread_id = 0.
This uses -1 to represent erased thread id.
diff --git a/src/trace_processor/importers/etw/etw_parser.cc b/src/trace_processor/importers/etw/etw_parser.cc
index 1aba1d0..3ff290a 100644
--- a/src/trace_processor/importers/etw/etw_parser.cc
+++ b/src/trace_processor/importers/etw/etw_parser.cc
@@ -67,8 +67,14 @@
int32_t old_thread_state = cs.has_old_thread_state()
? cs.old_thread_state()
: cs.old_thread_state_int();
- PushSchedSwitch(cpu, timestamp, cs.old_thread_id(), old_thread_state,
- cs.new_thread_id(), cs.new_thread_priority());
+ // thread_id might be erased for privacy/security concerns, in this case, use
+ // a dummy id since 0 means idle.
+ uint32_t old_thread_id =
+ cs.has_old_thread_id() ? cs.old_thread_id() : uint32_t(-1);
+ uint32_t new_thread_id =
+ cs.has_new_thread_id() ? cs.new_thread_id() : uint32_t(-1);
+ PushSchedSwitch(cpu, timestamp, old_thread_id, old_thread_state,
+ new_thread_id, cs.new_thread_priority());
}
void EtwParser::ParseReadyThread(int64_t timestamp, ConstBytes blob) {
