[Webkit-unassigned] [Bug 31931] New: CPU spikes when rendering, spending time loading compressed pcf fonts

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=31931

           Summary: CPU spikes when rendering, spending time loading
                    compressed pcf fonts
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: PC
        OS/Version: Mac OS X 10.5
            Status: UNCONFIRMED
          Severity: Normal
          Priority: P2
         Component: WebKit Gtk
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: pclouds at gmail.com


Hi,

I don't know if this is WebKit bug or cairo/freetype. About a month ago, every
time I surfed pages with CJK letters inside, CPU went up 100% for a while, then
back to normal. Recently this happens more often even with pages that have no
CJK letters. I ran with gdb and stopped the program a few times while CPU
spiked and got this call trace

#0  0xb5af410b in pcf_load_font () from /usr/lib/libfreetype.so.6
#1  0xb5af55c7 in PCF_Face_Init () from /usr/lib/libfreetype.so.6
#2  0xb5aad6b5 in open_face () from /usr/lib/libfreetype.so.6
#3  0xb5aaefb9 in FT_Open_Face () from /usr/lib/libfreetype.so.6
#4  0xb5ab0e66 in FT_New_Face () from /usr/lib/libfreetype.so.6
#5  0xb5ee858b in cairo_ft_scaled_font_lock_face () from /usr/lib/libcairo.so.2
#6  0xb7b23c72 in WebCore::SimpleFontData::containsCharacters () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#7  0xb7af8948 in WebCore::FontCache::getFontDataForCharacters () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#8  0xb78322cb in WebCore::Font::glyphDataForCharacter () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#9  0xb78411bb in WebCore::WidthIterator::advance () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#10 0xb7831a60 in WebCore::Font::floatWidthForSimpleText () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#11 0xb782a99d in WebCore::Font::floatWidth () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#12 0xb78ab2ec in WebCore::RenderBlock::findNextLineBreak () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#13 0xb78ad6b7 in WebCore::RenderBlock::layoutInlineChildren () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2
#14 0xb789fd56 in WebCore::RenderBlock::layoutBlock () from
/home/pclouds/opt/webkit/lib/libwebkit-1.0.so.2

OProfile said most of time was spent inside zlib, which was probably because
all my pcf fonts were compressed.

I tested with WebKit r51413, cairo 1.8.8, freetype 2.3.11. An easy test is open
yahoo.co.jp. My PCF fonts are baemuk-fonts, font-adobe-75dpi, font-cursor-misc,
font-misc-misc, unifont (Gentoo package names). Any suggestions how to find out
where the bottleneck is?

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.