[FFmpeg-devel] [RFC] Runtime-inited versus Hardcoded tables.

[Reimar Döffinger]

Hello,
On Thu, Jan 31, 2008 at 10:03:18AM +0100, Zdenek Kabelac wrote:
> 2008/1/31, Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> > On Thu, Jan 31, 2008 at 02:12:23AM +0100, Michael Niedermayer wrote:
> > > $free -m
> > >              total       used       free     shared    buffers     cached
> > > Mem:           181        177          3          0          0         49
> > > -/+ buffers/cache:        127         53
> > > Swap:          980        357        622
> > >
> > > And which OSs dont support COW?
> >
> > What does COW even matter here? This is about .rodata, with the right
> > linker hacks that can even be shared on MMU-less systems.
> > And even the experimental OS I wrote during my time as a student,
> > despite not getting further than running a very basic shell without a
> > proper filesystem supported COW...
> 
> And now I'm getting curious, how do you want to make COW with MMU-less
> system - was your system running in some emulator/valgrind-like mode
> ?

No, I am not aware of a way to implement COW without MMU, I was trying
to say that for one of the approaches (hard coded constant tables) no
COW and no MMU is needed.
And I was meaning to say that if you have an MMU COW is almost
trivial to implement, whereas supporting dynamic loading/swapping of
.rodata from the binary can be more painful.