Is it possible just to recompile libfb and replace it?

Adam Jackson ajax at
Tue Nov 7 15:35:56 PST 2006

On Wednesday 01 November 2006 10:43, Clemens Eisserer wrote:
> Hi there,
> When looking at usual oprofile results I see a lot of time spent in
> libfb, however I am using FC6 which is compiled for i586 or i686.
> Would it be possible to download xorg-7.1 and recompile it with really
> agresisve optimizations (auto-vectorization, sse2, -O3,
> -fomit-frame-pointer, ...) and just to exchange this single library or
> should I expect problems?

You can try.  Don't break the calling convention or you'll be sorry.

And really, if you're using FC6, it's much easier to just rebuild the server 
SRPM in mock with the CFLAGS you want, since mock will handle populating the 
necessary build-deps and you'll end up with a server otherwise configured the 
way FC6 did it.  See the Fedora wiki for details.

That said I would be pretty surprised if you saw any appreciable improvement 
by doing this.  The time spent in libfb is generally not slow on account of 
underoptimization; it's slow because touching pixels on the other side of the 
PCI bus from you is intrinsically not fast.

- ajax
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
URL: <>

More information about the xorg mailing list