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 +136,35 @@
         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}
+
+    def write_results(self, tests, elapsed):
+        # Find when first test started so we can make start times relative.
+        first_start_time = min([t.result.start for t in tests])
+        events = [self._get_test_event(
+            x, first_start_time) for x in tests if x.result.code not in self.skipped_codes]
+
+        json_data = {'traceEvents': events}
+
+        with open(self.output_file, "w") as time_trace_file:
+            json.dump(json_data, time_trace_file, indent=2, sort_keys=True)
+
+    def _get_test_event(self, test, first_start_time):
+        test_name = test.getFullName()
+        elapsed_time = test.result.elapsed or 0.0
+        start_time = test.result.start - first_start_time if test.result.start else 0.0
+        pid = test.result.pid or 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
 
 
Index: llvm/utils/lit/tests/time-trace-output.py
===================================================================
--- /dev/null
+++ llvm/utils/lit/tests/time-trace-output.py
@@ -0,0 +1,15 @@
+# RUN: %{lit} -j 1 -v %{inputs}/test-data --time-trace-output %t.json > %t.out
+# RUN: FileCheck < %t.json %s
+
+# CHECK: {
+# CHECK-NEXT: "traceEvents": [
+# CHECK-NEXT: {
+# CHECK-NEXT: "dur":
+# CHECK-NEXT: "name": "test-data :: metrics.ini"
+# CHECK-NEXT: "ph": "X"
+# CHECK-NEXT: "pid"
+# CHECK-NEXT: "tid": 1
+# CHECK-NEXT: "ts":
+# CHECK-NEXT: }
+# CHECK-NEXT: ]
+# CHECK-NEXT: }