diff --git a/polygerrit-ui/app/elements/core/gr-reporting/gr-reporting.js b/polygerrit-ui/app/elements/core/gr-reporting/gr-reporting.js
index 6306933399..5cd4e97924 100644
--- a/polygerrit-ui/app/elements/core/gr-reporting/gr-reporting.js
+++ b/polygerrit-ui/app/elements/core/gr-reporting/gr-reporting.js
@@ -142,6 +142,22 @@
   };
   catchErrors();
 
+  // PerformanceObserver interface is a browser API.
+  if (PerformanceObserver) {
+    const catchLongJsTasks = new PerformanceObserver(list => {
+      for (const task of list.getEntries()) {
+        // We are interested in longtask longer than 200 ms (default is 50 ms)
+        if (task.duration > 200) {
+          GrReporting.prototype.reporter(TIMING.TYPE,
+              TIMING.CATEGORY_UI_LATENCY, `Task ${task.name}`,
+              Math.round(task.duration), false);
+        }
+      }
+    });
+    catchLongJsTasks.observe({entryTypes: ['longtask']});
+  }
+
+
   // The Polymer pass of JSCompiler requires this to be reassignable
   // eslint-disable-next-line prefer-const
   let GrReporting = Polymer({