[XeTeX] wrong kerning and slow processing with xelatex in texlive 2010

[Vadim Radionov]

> Do Cyrillic small capital letters exist? I would have thought they're
> typical Latin...

Only few cyrillic letter have different capital shapes, probably
that's why they are no so popular.
Anyway, many perfect modern fonts have them.

> I don't have fontspec version 2.x around, but Will wrote that he changed
> many things, in xltxtra as well. Could you compare the definition of \textsc
> in the two fontspec versions you are using?

This is probably not a fontspec issue.  This example

\font\a = "CharterITC"
\font\b = "CharterITC:+smcp"
\b тар \a оттого
\end

also gives good kerning with xetex

XeTeX 3.141592-0.996-patch1 (Web2C 7.5.6)
kpathsea version 3.5.6
Compiled with ICU version 3.4 [with modifications for XeTeX]
Compiled with zlib version 1.2.3.3; using 1.2.3.3
Compiled with FreeType2 version 2.3.5; using 2.3.9
Compiled with fontconfig version 2.5.0; using 2.5.0
Compiled with libpng version 1.2.15beta5; using 1.2.15beta5
Compiled with libpoppler version 3.00

and wrong with

XeTeX 3.1415926-2.2-0.9997.4 (TeX Live 2010)
kpathsea version 6.0.0
Compiled with ICU version 4.4 [with modifications for XeTeX]
Compiled with zlib version 1.2.3; using 1.2.3
Compiled with FreeType2 version 2.3.11; using 2.3.11
Compiled with fontconfig version 2.3.1; using 2.5.0
Compiled with libpng version 1.2.40; using 1.2.40
Compiled with xpdf version 3.02pl4

Vadim