時計解像度

データ型 DOMHighResTimeStamp

[3] DOMデータ型 DOMHighResTimeStamp は、 高精度の時刻印 (タイムスタンプ) を表します。

仕様書

意味

[29] DOMHighResTimeStamp は、

... のいずれかを表します >>28

[25] DOMHighResTimeStamp は、既存の DateDOMTimeStamp では次のような場合に問題があるとして、導入されました >>24

[4] Web IDL 的には DOMHighResTimeStamp型定義であり、 実際のデータ型double です >>28

[33] 値は、ミリ秒単位の時刻とするべきです >>28

[32] 5マイクロ秒精度の値とするべきです >>28。 それが実現できない場合には、ミリ秒精度の値とすることができます >>28

[5] かつての規定では、ナノ秒の精度とするべき、それが実現できない場合には、 ミリ秒の精度の値とすることができる >>2 とされていました。

[36] 単位ms なので、それより精度が高い時は、小数で表されます。

文脈

[34] Performance API で使われています。

[35] timeRemaining が返す残り時間の値として使われます。

[39] Event インターフェイスtimeStamp IDL属性で使われています。

[60] Window最終活性化時刻印は、 DOMHighResTimeStamp または無限大です。

歴史

[7] IRC logs: freenode / #whatwg / 20140505 ( ( 版)) http://krijnhoetmer.nl/irc-logs/whatwg/20140505#l-231

[8] Re: [whatwg] Proposal: Event.creationTime ( (Anne van Kesteren 著, 版)) http://lists.w3.org/Archives/Public/public-whatwg-archive/2014May/0051.html

[9] IRC logs: freenode / #whatwg / 20150611 ( 版) http://krijnhoetmer.nl/irc-logs/whatwg/20150611

[10] High Resolution Time Level 2 ( 版) http://www.w3.org/TR/2015/WD-hr-time-2-20150617/

[11] High Resolution Time Level 2 ( ( 版)) http://www.w3.org/TR/2015/WD-hr-time-2-20150714/

[12] High Resolution Time Level 2 ( 版) http://www.w3.org/TR/2015/WD-hr-time-2-20150714/

[13] High Resolution Time Level 2 ( 版) http://www.w3.org/TR/2015/WD-hr-time-2-20150717/

[14] High Resolution Time Level 2 ( 版) http://www.w3.org/TR/2015/WD-hr-time-2-20150718/

[15] High Resolution Time Level 2 ( 版) http://www.w3.org/TR/2015/WD-hr-time-2-20150721/

[16] event.timeStamp now returns DOMHighResTimeStamp on Nightly/Aurora for Linux (Affected) | Firefox Site Compatibility ( ()) https://www.fxsitecompat.com/en-CA/docs/2015/event-timestamp-now-returns-domhighrestimestamp-on-nightly-aurora-for-linux/

[17] High resolution timing for events · Issue #23 · whatwg/dom ( ()) https://github.com/whatwg/dom/issues/23

[18] 77992 – Make Event.timeStamp return a DOMHighResTimeStamp on Windows (was Event.timeStamp should be relative to 1st January 1970 rather than the system start) ( ()) https://bugzilla.mozilla.org/show_bug.cgi?id=77992

[19] 1026804 – Make Event.timeStamp return a DOMHighResTimeStamp by default (switch on pref) ( ()) https://bugzilla.mozilla.org/show_bug.cgi?id=1026804

[20] receivedTime and upcoming DOM update · Issue #145 · WebAudio/web-midi-api ( ()) https://github.com/WebAudio/web-midi-api/issues/145

[21] [whatwg] Proposal: Event.creationTime ( (Brian Birtles著, )) https://lists.w3.org/Archives/Public/public-whatwg-archive/2014May/0046.html

[22] Issue 574514 - chromium - MSE conformance test failure related to event.timeStamp - Monorail ( ()) https://bugs.chromium.org/p/chromium/issues/detail?id=574514

[6] High Resolution Timestamps for Events | Web Updates - Google Developers ( ()) https://developers.google.com/web/updates/2016/01/high-res-timestamps

[37] Large rewrite/refactoring of the spec (#156) (tobie著, ) https://github.com/w3c/sensors/commit/615141fdd299e63e221a87d27f83766f345829e9

[38] Make Event's timeStamp use DOMHighResTimeStamp (majido著, ) https://github.com/whatwg/dom/commit/912d58746bc4c67c2fd210124639f7c34991fce5

[40] High resolution timing for events · Issue #23 · whatwg/dom () https://github.com/whatwg/dom/issues/23

[41] High resolution timing for events · Issue #23 · whatwg/dom () https://github.com/whatwg/dom/issues/23

[42] Update Event.timeStamp type to DOMHighResTimeStamp. by majido · Pull Request #420 · whatwg/dom () https://github.com/whatwg/dom/pull/420

[43] Is DOMHighResTimeStamp a "JSON type"? · Issue #504 · heycam/webidl () https://github.com/heycam/webidl/issues/504

[44] Temporarily reducing precision of DOMHighResTimeStamp in Chrome (Ross McIlroy著, ) https://lists.w3.org/Archives/Public/public-web-perf/2018Jan/0005.html

[45] Actions required to mitigate Speculative Side-Channel Attack techniques - The Chromium Projects () https://www.chromium.org/Home/chromium-security/ssca

[46] Mitigating speculative execution side-channel attacks in Microsoft Edge and Internet Explorer - Microsoft Edge Dev BlogMicrosoft Edge Dev Blog () https://blogs.windows.com/msedgedev/2018/01/03/speculative-execution-mitigations-microsoft-edge-internet-explorer/

[47] Mitigations landing for new class of timing attack | Mozilla Security Blog () https://blog.mozilla.org/security/2018/01/03/mitigations-landing-new-class-timing-attack/

[48] Speculative execution side-channel attack ("Spectre") — Mozilla () https://www.mozilla.org/en-US/security/advisories/mfsa2018-01/

[49] What Spectre and Meltdown Mean For WebKit | WebKit () https://webkit.org/blog/8048/what-spectre-and-meltdown-mean-for-webkit/

[50] metric -> name, value -> duration, duration as DOMHighResTimestamp (Charles Vazac著, ) https://github.com/w3c/server-timing/commit/48fcadffbb8ec4cf23404f681c607b2146c76078

[51] 165503 – performance.now() should truncate to 100us () https://bugs.webkit.org/show_bug.cgi?id=165503

[52] Temporarily reducing precision of DOMHighResTimeStamp in Chrome (Ross McIlroy著, ) https://lists.w3.org/Archives/Public/public-web-perf/2018Jan/0005.html

[53] Add a note regarding HRT precision (#57) (plehegar著, ) https://github.com/w3c/hr-time/commit/c7924fffdca73f8cf5ee057450a4ad9a5a73d645

[54] Add a note regarding HRT precision by plehegar · Pull Request #57 · w3c/hr-time () https://github.com/w3c/hr-time/pull/57

[55] Removed minimum resolution mention from SOTD (plehegar著, ) https://github.com/w3c/hr-time/commit/5220e4b80d62c4784c214dd66935e51366210680

[56] Define the reference clock used for RTCRtpContributingSource.timestamp ( (taylor-b著, ) https://github.com/w3c/webrtc-pc/commit/2820f6095ba81e018355260c4fdb801f311f4417

[57] RTCRtpContributingSource.timestamp needs a clearer definition · Issue #1690 · w3c/webrtc-pc () https://github.com/w3c/webrtc-pc/issues/1690

[58] Not possible to tell how old `RTCRtpContributingSource.timestamp` is · Issue #1497 · w3c/webrtc-pc () https://github.com/w3c/webrtc-pc/issues/1497

[59] Define the reference clock used for RTCRtpContributingSource.timestamp by taylor-b · Pull Request #1854 · w3c/webrtc-pc () https://github.com/w3c/webrtc-pc/pull/1854