| <!DOCTYPE HTML> |
| <html> |
| <head> |
| <script src="/resources/testharness.js"></script> |
| <script src="/resources/testharnessreport.js"></script> |
| </head> |
| <body> |
| <script> |
| function testTimeResolution(highResTimeFunc, funcString) { |
| test(() => { |
| const t0 = highResTimeFunc(); |
| let t1 = highResTimeFunc(); |
| while (t0 == t1) { |
| t1 = highResTimeFunc(); |
| } |
| assert_greater_than_equal(t1 - t0, 0.02, 'The second ' + funcString + ' should be much greater than the first'); |
| }, 'Verifies the resolution of ' + funcString + ' is at least 20 microseconds.'); |
| } |
| |
| function timeByPerformanceNow() { |
| return performance.now(); |
| } |
| |
| function timeByUserTiming() { |
| performance.mark('timer'); |
| const time = performance.getEntriesByName('timer')[0].startTime; |
| performance.clearMarks('timer'); |
| return time; |
| } |
| |
| testTimeResolution(timeByPerformanceNow, 'performance.now()'); |
| testTimeResolution(timeByUserTiming, 'entry.startTime'); |
| </script> |
| </body> |
| </html> |
