fltk and Xinerama

[jhhaynes]

I compiled an application that links with the fltk library. It insisted that I also link with
the Xinerama library. When it runs the Xserver takes up about 50% of the available
CPU time. I then compiled my own fltk library, not enabling Xinerama, and linked with
that. This application runs fine, with quite low CPU loading from the X server.

So what is it about using the distribution-supplied fltk and Xinerama that causes such
excessive CPU burning? I've done this on F8 and F9 with the same results.

[RupertPupkin]

Interesting. I've noticed that some apps and libraries shipped with Fedora are linked against a lot more libraries than is necessary. Run ldd against the Fedora-supplied fltk shared library and then run it against the one you compiled, then compare. On my F7 system I get this with the Fedora fltk shared library:

$ ldd /usr/lib/libfltk.so.1.1
        linux-gate.so.1 =>  (0xffffe000)
        libXft.so.2 => /usr/lib/libXft.so.2 (0xb7e6b000)
        libXinerama.so.1 => /usr/lib/libXinerama.so.1 (0xb7e68000)
        libpthread.so.0 => /lib/libpthread.so.0 (0xb7e50000)
        libdl.so.2 => /lib/libdl.so.2 (0xb7e4b000)
        libXext.so.6 => /usr/lib/libXext.so.6 (0xb7e3a000)
        libX11.so.6 => /usr/lib/libX11.so.6 (0xb7d38000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7c4d000)
        libm.so.6 => /lib/libm.so.6 (0xb7c24000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7c18000)
        libc.so.6 => /lib/libc.so.6 (0xb7ac4000)
        libfontconfig.so.1 => /usr/lib/libfontconfig.so.1 (0xb7a94000)
        libfreetype.so.6 => /usr/lib/libfreetype.so.6 (0xb7a0a000)
        libXrender.so.1 => /usr/lib/libXrender.so.1 (0xb7a01000)
        /lib/ld-linux.so.2 (0x80000000)
        libXau.so.6 => /usr/lib/libXau.so.6 (0xb79fe000)
        libXdmcp.so.6 => /usr/lib/libXdmcp.so.6 (0xb79f8000)
        libexpat.so.0 => /lib/libexpat.so.0 (0xb79d6000)

If your fltk library is lighter and faster, I'd just use that and uninstall the Fedora one.

[jhhaynes]

Well that's what I did, but I wish somebody who understands these things would figure out why
the Fedora one causes the problem so I wouldn't have to work around it. Maybe I should file a bug
report.