Distinct performance issues with Japanese only on win32 systems


I have noticed significant performance issues with pango when
displaying Japanese text on win32 systems.  Thus far, I've assumed
that this was a configuration issue, but I've encountered the problem
using the stock gtk+ win32 binaries on what I believe is a standard
msys/mingw setup on both English and Japanese versions of Windows XP.

In addition to using the stock pango, I've tried building pango myself
using different versions, I've checked pango.modules and
pango.aliases, and I've tried various combinations of LANG and Windows
language settings; the numbers below are the best I've obtained for
each over multiple runs.

Here's the sort of timing I'm seeing for pango_layout_check_lines()
for the test files referenced below:

English (10.9k bytes/chars)  Japanese file (12.6k bytes, 4.5k chars)
34ms                         57ms         Linux setup
10ms                        940ms         Windows setup

Obviously the particular values will vary by system, but my machine is
a year-old developer-class machine, and 940ms is long in human terms.

Some brief explorations suggest that the 940ms case involves making
many calls to Uniscribe (each roughly 10ms in cost), but since
Japanese is not a complex script, it is unclear to me why layout would
require Uniscribe at all.

The files referenced above can be found here:

http://www.fastanimals.com/tech/pango/pango-test1.c      (Linux file)
http://www.fastanimals.com/tech/pango/pango-win-test1.c  (Windows file)
http://www.fastanimals.com/tech/pango/udhr-en.txt        (English)
http://www.fastanimals.com/tech/pango/udhr-ja.txt        (Japanese)
http://www.gtk.org/download-windows.html                 (gtk All-in-one bundle)
http://www.mingw.org/wiki/msys                           (msys/mingw)

I would appreciate it if someone else would try compiling
pango-win-test1.c to see if they have similar results.

Thank you for any suggestions on how to proceed,

David E Hollingsworth
deh curl com

"I've just found the silverware and I'm sticking a fork in that square!" - N.H.

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