[Fedora-livecd-list] Performance

[Albert Strasheim]

Hello all

On Thu, 01 Sep 2005, jeff wrote:

> Glen Eustace wrote:
> >It may be worthwhile thinking about how to improve the performance by
> >coping more stuff into the RAM Disk. In my case there is a trade off
> >between the initial boot speed and the speed of the application. If it
> >takes too long to boot because of the copies, the users will get
> >annoyed.  It seems somehow better to have things actually happening on
> >the screen even though they are a little sluggish to start with.
> 
> For performance a few things have come to mind.
> 
> 1) What about running the prelinker in the chroot before the ISO is rolled?

Cool idea.

> <snip>

> 4) By listening to the booting of the CD, it sounds like the head of the 
> CD drive seeks quite a bit. Is there any optimization we can do so the 
> CD can be read (more) sequentially?

mkisofs and SquashFS both support the idea of prioritising files to 
indicate where they should be placed on the image (see the -sort option 
in the mkisofs man page).

This way, you can determine whether files are added to the start of the 
image, i.e. the middle of the CD, where reading them is slow, or at the 
end of the image, i.e. the edge of the image, where reading is faster.

If we can find a way of instrumenting the boot process to get a list of 
files used during boot, a priority list can be built automatically. The 
boot files can probably be followed by everything in the bin and lib 
directories and then the remaining biggest files in the installation.

Cheers

Albert