Merge "tp: extract the event id in the ftrace tokenizer" into main
diff --git a/src/trace_processor/importers/ftrace/ftrace_tokenizer.cc b/src/trace_processor/importers/ftrace/ftrace_tokenizer.cc
index c699ab9..711415f 100644
--- a/src/trace_processor/importers/ftrace/ftrace_tokenizer.cc
+++ b/src/trace_processor/importers/ftrace/ftrace_tokenizer.cc
@@ -53,6 +53,47 @@
return context->clock_tracker->ToTraceTime(clock_id, ts);
}
+// Fast path for parsing the event id of an ftrace event.
+// Speculate on the fact that, if the timestamp was found, the common pid
+// will appear immediately after and the event id immediately after that.
+uint64_t TryFastParseFtraceEventId(const uint8_t* start, const uint8_t* end) {
+ constexpr auto kPidFieldNumber = protos::pbzero::FtraceEvent::kPidFieldNumber;
+ constexpr auto kPidFieldTag = MakeTagVarInt(kPidFieldNumber);
+
+ // If the next byte is not the common pid's tag, just skip the field.
+ constexpr uint32_t kMaxPidLength = 5;
+ if (PERFETTO_UNLIKELY(static_cast<uint32_t>(end - start) <= kMaxPidLength ||
+ start[0] != kPidFieldTag)) {
+ return 0;
+ }
+
+ // Skip the common pid.
+ uint64_t common_pid = 0;
+ const uint8_t* common_pid_end = ParseVarInt(start + 1, end, &common_pid);
+ if (PERFETTO_UNLIKELY(common_pid_end == start + 1)) {
+ return 0;
+ }
+
+ // Read the next varint: this should be the event id tag.
+ uint64_t event_tag = 0;
+ const uint8_t* event_id_end = ParseVarInt(common_pid_end, end, &event_tag);
+ if (event_id_end == common_pid_end) {
+ return 0;
+ }
+
+ constexpr uint8_t kFieldTypeNumBits = 3;
+ constexpr uint64_t kFieldTypeMask =
+ (1 << kFieldTypeNumBits) - 1; // 0000 0111;
+
+ // The event wire type should be length delimited.
+ auto wire_type = static_cast<protozero::proto_utils::ProtoWireType>(
+ event_tag & kFieldTypeMask);
+ if (wire_type != protozero::proto_utils::ProtoWireType::kLengthDelimited) {
+ return 0;
+ }
+ return event_tag >> kFieldTypeNumBits;
+}
+
} // namespace
PERFETTO_ALWAYS_INLINE
@@ -125,29 +166,53 @@
const uint8_t* data = event.data();
const size_t length = event.length();
- ProtoDecoder decoder(data, length);
- // Speculate on the fact that the timestamp is often the 1st field of the
- // event.
+ // Speculate on the following sequence of varints
+ // - timestamp tag
+ // - timestamp (64 bit)
+ // - common pid tag
+ // - common pid (32 bit)
+ // - event tag
uint64_t raw_timestamp = 0;
bool timestamp_found = false;
+ uint64_t event_id = 0;
if (PERFETTO_LIKELY(length > 10 && data[0] == kTimestampFieldTag)) {
// Fastpath.
- const uint8_t* next = ParseVarInt(data + 1, data + 11, &raw_timestamp);
- timestamp_found = next != data + 1;
- decoder.Reset(next);
- } else {
- // Slowpath.
+ const uint8_t* ts_end = ParseVarInt(data + 1, data + 11, &raw_timestamp);
+ timestamp_found = ts_end != data + 1;
+ if (PERFETTO_LIKELY(timestamp_found)) {
+ event_id = TryFastParseFtraceEventId(ts_end, data + length);
+ }
+ }
+
+ // Slowpath for finding the timestamp.
+ if (PERFETTO_UNLIKELY(!timestamp_found)) {
+ ProtoDecoder decoder(data, length);
if (auto ts_field = decoder.FindField(kTimestampFieldNumber)) {
timestamp_found = true;
raw_timestamp = ts_field.as_uint64();
}
+ if (PERFETTO_UNLIKELY(!timestamp_found)) {
+ context_->storage->IncrementStats(stats::ftrace_bundle_tokenizer_errors);
+ return;
+ }
}
- if (PERFETTO_UNLIKELY(!timestamp_found)) {
- PERFETTO_ELOG("Timestamp field not found in FtraceEvent");
- context_->storage->IncrementStats(stats::ftrace_bundle_tokenizer_errors);
- return;
+ // Slowpath for finding the event id.
+ if (PERFETTO_UNLIKELY(event_id == 0)) {
+ ProtoDecoder decoder(data, length);
+ for (auto f = decoder.ReadField(); f.valid(); f = decoder.ReadField()) {
+ // Find the first length-delimited tag as this corresponds to the ftrace
+ // event.
+ if (f.type() == protozero::proto_utils::ProtoWireType::kLengthDelimited) {
+ event_id = f.id();
+ break;
+ }
+ }
+ if (PERFETTO_UNLIKELY(!event_id)) {
+ context_->storage->IncrementStats(stats::ftrace_bundle_tokenizer_errors);
+ return;
+ }
}
// ClockTracker will increment some error stats if it failed to convert the
