We could reduce layout time by appending system fallback FontData to FontFallbackList.
Created attachment 190433 [details] Patch
Comment on attachment 190433 [details] Patch Attachment 190433 [details] did not pass qt-ews (qt): Output: http://webkit-commit-queue.appspot.com/results/16767027
Comment on attachment 190433 [details] Patch Attachment 190433 [details] did not pass qt-wk2-ews (qt): Output: http://webkit-commit-queue.appspot.com/results/16672138
Comment on attachment 190433 [details] Patch Attachment 190433 [details] did not pass chromium-ews (chromium-xvfb): Output: http://webkit-commit-queue.appspot.com/results/16805023
Created attachment 190436 [details] Patch
Comment on attachment 190436 [details] Patch Attachment 190436 [details] did not pass mac-wk2-ews (mac-wk2): Output: http://webkit-commit-queue.appspot.com/results/16806085 New failing tests: css2.1/t0905-c414-flt-fit-01-d-g.html fast/text/international/danda-space.html fast/text/international/bidi-mirror-he-ar.html
Comment on attachment 190436 [details] Patch Attachment 190436 [details] did not pass chromium-ews (chromium-xvfb): Output: http://webkit-commit-queue.appspot.com/results/16667135 New failing tests: fast/text/emphasis-combined-text.html css2.1/20110323/word-spacing-characters-002.htm
Comment on attachment 190436 [details] Patch Attachment 190436 [details] did not pass mac-ews (mac): Output: http://webkit-commit-queue.appspot.com/results/16829028 New failing tests: css2.1/t0905-c414-flt-fit-01-d-g.html fast/text/international/danda-space.html fast/text/international/bidi-mirror-he-ar.html
Comment on attachment 190436 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=190436&action=review > Source/WebCore/ChangeLog:14 > + No new tests, covered by existing tests. How is this covered by existing tests? You are adding this because you say it improves performance. Do you have data on this performance improvement or a test case to demonstrate the speed improvement?
Comment on attachment 190436 [details] Patch review- because this breaks regression tests as seen on the mac and mac-wk2 EWS results
Webkit dose not cache the fallback fontData. So it takes a long time to create same fallback fontData during layout especially at CJK web pages. Because CJK fontData is usually created using fallback font. This patch is just for caching fallback fontData and it improves performance when fallback fontData is used. The performance time of FrameView::layout is decreased after applying the patch : 232 milliseconds(before) -> 151 milliseconds (after) Test site : m.naver.com (Korean web page)