Add the thread name as metadata to the Json profile

PiperOrigin-RevId: 205985818

1 files changed, 33 insertions, 5 deletions

diff --git a/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java b/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
index 47008de2be..4f1ccb80ae 100644
--- a/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
+++ b/src/main/java/com/google/devtools/build/lib/profiler/Profiler.java
@@ -990,12 +990,30 @@ public final class Profiler {
   private static class JsonTraceFileWriter extends FileWriter {
     private final OutputStream outStream;
     private final long profileStartTimeNanos;
+    private final ThreadLocal<Boolean> metadataPosted =
+        ThreadLocal.withInitial(() -> Boolean.FALSE);
 
     JsonTraceFileWriter(OutputStream outStream, long profileStartTimeNanos) {
       this.outStream = outStream;
       this.profileStartTimeNanos = profileStartTimeNanos;
     }
 
+    @Override
+    public void enqueue(TaskData data) {
+      if (!metadataPosted.get().booleanValue()) {
+        metadataPosted.set(Boolean.TRUE);
+        // Create a TaskData object that is special-cased below.
+        queue.add(
+            new TaskData(
+                /* id= */ 0,
+                /* startTimeNanos= */ -1,
+                /* parent= */ null,
+                ProfilerTask.THREAD_NAME,
+                Thread.currentThread().getName()));
+      }
+      queue.add(data);
+    }
+
     /**
      * Saves all gathered information from taskQueue queue to the file.
      * Method is invoked internally by the Timer-based thread and at the end of
@@ -1010,17 +1028,27 @@ public final class Profiler {
             // in the future.
             new OutputStreamWriter(
                 new BufferedOutputStream(outStream, 262144), StandardCharsets.UTF_8)) {
-          out.append("[");
+          out.append("[\n");
           boolean first = true;
           TaskData data;
           while ((data = queue.take()) != POISON_PILL) {
-            if (data.duration == 0) {
+            if (data.duration == 0 && data.type != ProfilerTask.THREAD_NAME) {
               continue;
             }
             if (first) {
               first = false;
             } else {
-              out.append(",");
+              out.append(",\n");
+            }
+            if (data.type == ProfilerTask.THREAD_NAME) {
+              out.append("{");
+              out.append("\"name\":\"thread_name\",");
+              out.append("\"ph\":\"M\",");
+              out.append("\"pid\":1,");
+              out.append("\"tid\":").append(Long.toString(data.threadId)).append(",");
+              out.append("\"args\": {\"name\":\"").append(data.description).append("\"}");
+              out.append("}");
+              continue;
             }
             char eventType = data.duration == 0 ? 'i' : 'X';
             out.append("{");
@@ -1039,10 +1067,10 @@ public final class Profiler {
             }
             out.append("\"pid\":1,");
             out.append("\"tid\":").append(Long.toString(data.threadId));
-            out.append("}\n");
+            out.append("}");
           }
           receivedPoisonPill = true;
-          out.append("]");
+          out.append("\n]");
         } catch (IOException e) {
           this.savedException = e;
           if (!receivedPoisonPill) {