105919 2013-01-02 04:47:58 -0800 Stylesheets that don't match current viewport etc. are no longer deferred 2013-04-08 15:31:35 -0700 1 1 1 Unclassified WebKit Page Loading 528+ (Nightly build) Mac OS X 10.8 NEW P2 Normal --- 1 dajdavies webkit-unassigned abarth ap beidson ddkilzer dglazkov japhet koivisto psolanki schenney simonjam webkit.review.bot yoav oldest_to_newest 798630 0 dajdavies 2013-01-02 04:47:58 -0800 Previous versions of WebKit deferred loading stylesheets where the media query didn't match viewport, orientation etc. This waterfall illustrates the behaviour in Chrome 23 - http://www.webpagetest.org/result/130102_CQ_0f4cca3d4aa1dff79941bb64eda548c9/1/details/ - where big.css is deferred, due to media="screen and (min-width : 1200px)" In Chrome 26, big.css is no longer deferred and so is competing for the network with other resources - http://www.webpagetest.org/result/130102_KJ_2079b3c622753c392584f48052d8a01c/1/details/ Also tested in r138591 801073 1 181459 yoav 2013-01-06 08:03:31 -0800 Created attachment 181459 Re-enabling the ResourceLoadScheduler This issue started in the disabling of the ResourceLoadScheduler for Chromium at the git commit 46e22591a4adb6bb42530b2f52e4517cd3b226bf. This patch reverses part of that commit. The reasoning for disabling the renderer's load scheduler is explained at https://insouciant.org/tech/throttling-subresources-before-first-paint/ and in short it is destined to move resource scheduling out of the rendering engine and into the browser. Since Chrome's resource scheduling is not yet in place (at least as I can tell), this results in obvious performance regressions, especially when it comes to external CSS files that are not necessary for first paint. 801101 2 yoav 2013-01-06 14:16:45 -0800 I've opened a slightly related bug regarding the PreloadScanner - https://bugs.webkit.org/show_bug.cgi?id=106198 801362 3 ap 2013-01-07 10:03:03 -0800 From the analysis above, this looks like a chromium-only issue. 801523 4 dajdavies 2013-01-07 12:02:35 -0800 I used webpagetest as it was the easiest way to provide waterfalls I also tested in WebKit r138591 and Safari 6.0.2 (8536.26.17) - Safari behaves the same a Chrome 23, WebKit nightly behaves as Chrome 26 That's why I raised it against WebKit rather than Chromium 801526 5 abarth 2013-01-07 12:03:25 -0800 This patch appears to be in the inverse of http://trac.webkit.org/changeset/129070 Perhaps you and simonjam should discuss this issue at bit. :) 801528 6 abarth 2013-01-07 12:03:51 -0800 Actually CC the folks from http://trac.webkit.org/changeset/129070 801529 7 abarth 2013-01-07 12:04:35 -0800 > That's why I raised it against WebKit rather than Chromium It's correct to raise this issue in bugs.webkit.org. Alexey is just marking the bug as only affecting Chromium so that he can ignore it. :) 801542 8 ap 2013-01-07 12:23:11 -0800 > Safari behaves the same a Chrome 23, WebKit nightly behaves as Chrome 26 If it's also broken in nightlies, then perhaps we have multiple issues. A fix that changes REQUEST_MANAGEMENT_ENABLED for Chromium won't fix Safari nightlies. 801837 9 simonjam 2013-01-07 16:57:33 -0800 As Alexey says, it's really only an issue if WebKit nightlies are affected. For Chrome, we have a browser based scheduler in the works and this bug doesn't affect stable or beta channel users. 817517 10 181459 webkit.review.bot 2013-01-27 22:00:36 -0800 Comment on attachment 181459 Re-enabling the ResourceLoadScheduler Attachment 181459 did not pass chromium-ews (chromium-xvfb): Output: http://queues.webkit.org/results/16156460 New failing tests: http/tests/css/link-css-disabled-value-with-slow-loading-sheet-in-error.html 817532 11 181459 webkit.review.bot 2013-01-27 22:58:34 -0800 Comment on attachment 181459 Re-enabling the ResourceLoadScheduler Attachment 181459 did not pass chromium-ews (chromium-xvfb): Output: http://queues.webkit.org/results/16150608 New failing tests: http/tests/css/link-css-disabled-value-with-slow-loading-sheet-in-error.html 181459 2013-01-06 08:03:31 -0800 2013-01-27 22:58:34 -0800 Re-enabling the ResourceLoadScheduler enable_load_scheduler.patch text/plain 467 yoav ZGlmZiAtLWdpdCBTb3VyY2UvV2ViQ29yZS9sb2FkZXIvUmVzb3VyY2VMb2FkU2NoZWR1bGVyLmNw cCBTb3VyY2UvV2ViQ29yZS9sb2FkZXIvUmVzb3VyY2VMb2FkU2NoZWR1bGVyLmNwcAppbmRleCBm YTNjMDk2Li4wNzI1NTIzIDEwMDY0NAotLS0gU291cmNlL1dlYkNvcmUvbG9hZGVyL1Jlc291cmNl TG9hZFNjaGVkdWxlci5jcHAKKysrIFNvdXJjZS9XZWJDb3JlL2xvYWRlci9SZXNvdXJjZUxvYWRT Y2hlZHVsZXIuY3BwCkBAIC00MiwxMSArNDIsNyBAQAogI2luY2x1ZGUgPHd0Zi9UZW1wb3JhcnlD aGFuZ2UuaD4KICNpbmNsdWRlIDx3dGYvdGV4dC9DU3RyaW5nLmg+CiAKLSNpZiBQTEFURk9STShD SFJPTUlVTSkKLSNkZWZpbmUgUkVRVUVTVF9NQU5BR0VNRU5UX0VOQUJMRUQgMAotI2Vsc2UKICNk ZWZpbmUgUkVRVUVTVF9NQU5BR0VNRU5UX0VOQUJMRUQgMQotI2VuZGlmCiAKIG5hbWVzcGFjZSBX ZWJDb3JlIHsKIAo=