This is an incomplete snippet - idea is to use greasemonky to measure the pageloadtime

pageLoadTime with greasemonky - alpha

// With GreaseMonkey create a new script that would look like the following:
// ==UserScript==
// @name        test
// @description test desc
// @include     *://www.mysite.com/*
// @grant       none
// @version    0.1
// ==/UserScript==

// (function() {
//     document.addEventListener("DOMContentLoaded", function(event) {
//         console.log("DOM fully loaded and parsed");
//         // Your code should be here.
//     });
// })();


/*
 * This is a JavaScript Scratchpad.
 *
 * Enter some JavaScript, then Right Click or choose from the Execute Menu:
 * 1. Run to evaluate the selected text (Ctrl+R),
 * 2. Inspect to bring up an Object Inspector on the result (Ctrl+I), or,
 * 3. Display to insert the result in a comment after the selection. (Ctrl+L)
 */

function KPI(key, value) {
  this.key = key;
  this.value = value;
}

function right(foo)
{
  var s =  foo.toString();
  var lastFive =  s.substring(s.length - 4);
  return lastFive;
}

function getPerformanceTimings()
{
  var t = window.performance.timing;  
  var timings = [];
  
  timings.push(["navigationStart", t.navigationStart, right(t.navigationStart) ] );
  timings.push(["connectStart", t.connectStart, right(t.connectStart) ] );
  timings.push(["requestStart",  t.requestStart, right(t.requestStart)] );   
  timings.push(["responseEnd", t.responseEnd, right(t.responseEnd) ] );
  timings.push(["PageLoadTime", ( t.loadEventEnd - t.navigationStart), 0 ] );
  // timings.push("navigationStart: " + t.navigationStart );
  // timings.push("responseEnd: " + t.responseEnd );
  
  // timings.push("PageLoadTime: " + ( t.loadEventEnd - t.navigationStart));
  // timings.push("DOMContentLoadedTime: " +  (t.domContentLoadedEventEnd - t.navigationStart ));
  // timings.push("ResponseTime: " + (t.responseEnd - t.requestStart) );
  // timings.push({ label: "Connection", time: t.connectEnd - t.connectStart });
  // timings.push({ label: "Response", time: t.responseEnd - t.responseStart });
  // timings.push({ label: "DomainLookup", time: t.domainLookupEnd - t.domainLookupStart  });
  // timings.push({ label: "LoadEvent", time: t.loadEventEnd - t.loadEventStart  });
  // timings.push({ label: "UnloadEvent", time: t.unloadEventEnd - t.unloadEventStart  });
  // timings.push({ label: "DOMContentLoadedEvent", time: t.domContentLoadedEventEnd - t.domContentLoadedEventStart  });

  // chrome.loadTimes will be removed see https://bugs.chromium.org/p/chromium/issues/detail?id=621512
  // var lt = window.chrome && window.chrome.loadTimes && window.chrome.loadTimes();
  // if(lt) {
    // if(lt.wasNpnNegotiated) { 
 //        timings.push({ label: "NPN negotiation protocol", time: lt.npnNegotiatedProtocol }); }
   //     timings.push({ label: "ConnectionInfo", time: lt.connectionInfo });
     //   timings.push({ label: "FirstPaintAfterDocumentLoad", time: Math.ceil(lt.firstPaintTime - lt.finishDocumentLoadTime)  });
  // }
  return timings;
  
  // return perf;
}

console.table(getPerformanceTimings())



/*
undefined
*/

snippets copied not working together yet