dom/tests/mochitest/general/test_performance_now.html@97036ab72558
dom/tests/mochitest/general/test_performance_now.html
Tue, 06 Jan 2015 21:39:09 +0100
- author
- Michael Schloh von Bennewitz <michael@schloh.com>
- date
- Tue, 06 Jan 2015 21:39:09 +0100
- branch
- TOR_BUG_9701
- changeset 8
- 97036ab72558
- permissions
- -rw-r--r--
Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.
1 <!DOCTYPE HTML>
2 <html>
3 <head>
4 <title>Test for High Resolution Timer</title>
5 <script type="text/javascript" src="/MochiKit/MochiKit.js"></script>
6 <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
7 <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
8 </head>
9 <body>
10 <script>
11 ok(window.performance, "Performance object should exist.");
12 ok(typeof window.performance.now == 'function', "Performance object should have a 'now' method.");
13 var n = window.performance.now(), d = Date.now();
14 ok(n >= 0, "The value of now() should be equal to or greater than 0.");
15 ok(window.performance.now() >= n, "The value of now() should monotonically increase.");
16 SimpleTest.waitForExplicitFinish();
18 // The spec says performance.now() should have micro-second resolution, but allows 1ms if the platform doesn't support it.
19 // Our implementation does provide micro-second resolution, except for windows XP combined with some HW properties
20 // where we can't use QueryPerformanceCounters (see comments at mozilla-central/xpcom/ds/TimeStamp_windows.cpp).
21 // This XP-low-res case results in about 15ms resolutions, and can be identified when perf.now() returns only integers.
22 //
23 // Since setTimeout might return too early/late, our goal is that perf.now() changed within 2ms
24 // (or 25ms for XP-low-res), rather than specific number of setTimeout(N) invocations.
25 // See bug 749894 (intermittent failures of this test)
26 var platformPossiblyLowRes = navigator.oscpu.indexOf("Windows NT 5.1") == 0; // XP only
27 var allInts = (n % 1) == 0; // Indicator of limited HW resolution.
28 var checks = 0;
30 function checkAfterTimeout() {
31 checks++;
32 var d2 = Date.now();
33 var n2 = window.performance.now();
35 allInts = allInts && (n2 % 1) == 0;
36 var lowResCounter = platformPossiblyLowRes && allInts;
38 if ( n2 == n && checks < 50 && // 50 is just a failsafe. Our real goals are 2ms or 25ms.
39 ( (d2 - d) < 2 // The spec allows 1ms resolution. We allow up to measured 2ms to ellapse.
40 ||
41 lowResCounter &&
42 (d2 - d) < 25
43 )
44 ) {
45 setTimeout(checkAfterTimeout, 1);
46 return;
47 }
49 // Loose spec: 1ms resolution, or 15ms resolution for the XP-low-res case.
50 // We shouldn't test that dt is actually within 2/25ms since the iterations break if it isn't, and timeout could be late.
51 ok(n2 > n, "Loose - the value of now() should increase within 2ms (or 25ms if low-res counter) (delta now(): " + (n2 - n) + " ms).");
53 // Strict spec: if it's not the XP-low-res case, while the spec allows 1ms resolution, it prefers microseconds, which we provide.
54 // Since the fastest setTimeout return which I observed was ~500 microseconds, a microseconds counter should change in 1 iteretion.
55 ok(n2 > n && (lowResCounter || checks == 1),
56 "Strict - [if high-res counter] the value of now() should increase after one setTimeout (hi-res: " + (!lowResCounter) +
57 ", iters: " + checks +
58 ", dt: " + (d2 - d) +
59 ", now(): " + n2 + ").");
60 SimpleTest.finish();
61 };
62 setTimeout(checkAfterTimeout, 1);
63 </script>
64 </body>
65 </html>
