Index: llvm/utils/lit/lit/Test.py
===================================================================
--- llvm/utils/lit/lit/Test.py
+++ llvm/utils/lit/lit/Test.py
@@ -150,6 +150,8 @@
         self.output = output
         # The wall timing to execute the test, if timing.
         self.elapsed = elapsed
+        self.start = None
+        self.pid = None
         # The metrics reported by this test.
         self.metrics = {}
         # The micro-test results reported by this test.
Index: llvm/utils/lit/lit/cl_arguments.py
===================================================================
--- llvm/utils/lit/lit/cl_arguments.py
+++ llvm/utils/lit/lit/cl_arguments.py
@@ -109,6 +109,9 @@
     execution_group.add_argument("--xunit-xml-output",
             type=lit.reports.XunitReport,
             help="Write XUnit-compatible XML test reports to the specified file")
+    execution_group.add_argument("--time-trace-output",
+            type=lit.reports.TimeTraceReport,
+            help="Write Chrome tracing compatible JSON to the specified file")
     execution_group.add_argument("--timeout",
             dest="maxIndividualTestTime",
             help="Maximum time to spend running a single test (in seconds). "
@@ -195,7 +198,7 @@
     else:
         opts.shard = None
 
-    opts.reports = filter(None, [opts.output, opts.xunit_xml_output])
+    opts.reports = filter(None, [opts.output, opts.xunit_xml_output, opts.time_trace_output])
 
     return opts
 
Index: llvm/utils/lit/lit/reports.py
===================================================================
--- llvm/utils/lit/lit/reports.py
+++ llvm/utils/lit/lit/reports.py
@@ -136,3 +136,36 @@
         if features:
             return 'Missing required feature(s): ' + ', '.join(features)
         return 'Unsupported configuration'
+
+class TimeTraceReport(object):
+    def __init__(self, output_file):
+        self.output_file = output_file
+        self.skipped_codes = {lit.Test.EXCLUDED,
+                              lit.Test.SKIPPED, lit.Test.UNSUPPORTED}
+
+    # TODO(yln): elapsed unused, put it somewhere?
+    def write_results(self, tests, elapsed):
+        events =  [self._get_test_event(x) for x in tests]
+        first_timestamp = min(e['ts'] for e in events)
+        #Rebase all timestamps which were stored as absolute times
+        for e in events:
+            e['ts'] = e['ts'] - first_timestamp
+
+        json_struct = {'traceEvents': events}
+
+        with open(self.output_file, "w") as time_trace_file:
+            json.dump(json_struct, time_trace_file, indent=2)
+
+    def _get_test_event(self, test):
+        test_name = test.getFullName()
+        elapsed_time = test.result.elapsed if test.result.elapsed is not None else 0.0
+        start_time = test.result.start if test.result.start is not None else 0.0
+        pid = test.result.pid if test.result.pid is not None else 0
+        return {
+            'pid': pid,
+            'tid': 1,
+            'ph': 'X',
+            'ts': int(start_time * 1000000.),
+            'dur': int(elapsed_time * 1000000.),
+            'name': test_name,
+        }
Index: llvm/utils/lit/lit/worker.py
===================================================================
--- llvm/utils/lit/lit/worker.py
+++ llvm/utils/lit/lit/worker.py
@@ -6,6 +6,7 @@
 and store it in global variables. This reduces the cost of each task.
 """
 import contextlib
+import os
 import signal
 import time
 import traceback
@@ -65,6 +66,8 @@
     start = time.time()
     result = _execute_test_handle_errors(test, lit_config)
     result.elapsed = time.time() - start
+    result.start = start
+    result.pid = os.getpid()
     return result