Cross Compile Howto?

[Pinn2]

Hi All

I've Googled around and searched here without success so can someone possibly point me in to right direction.

I have a few old Sony Picturebook machines that are 266Mhz Pentium II based and only 64MB of RAM, while they are pretty useless for most things they have 1024x480 screens and built in cameras and are therefore extremely useful for monitoring type applications (Ethereal, SNMP etc type stuff). I've got one setup with FC4 and XFCE and while functional it's painfully slow (mainly due to thrashing).

Due to the restrictions of FC5 and FC6 requiring a minimum of 128MB to do the installation I decided to compile my own Kernel based upon 2.6.20 to install on the machine, stripping out all the drivers and modules I don't need (this should reduce the footprint quite dramatically), I'll probably also end up compiling my own XFCE version once I've done the compile on the machine.

Now while there are a few HOWTO's around on compiling the Kernel I don't intend to compile the Kernel on a 266Mhz machine when I have a perfectly good Core 2 Duo machine that'll do it in a fraction of the time. Therefore can anyone point to a good up to date Howto on cross compiling using the GCC compiler? Else can anyone give me advice on how to go about it?

TIA

P

[Jman]

Pentium II is an i686 class processor. So, install i386 Fedora on Core 2 Duo machine and build minimal i686 kernel.

It can be done on x86_64, I forget how.

[fakie_flip]

I'm having no luck with cross compiling either. The crossdev script is for Gentoo only using distcc. I'm trying to use distcc to compile enlightenment and other things on a slow Debian p2 machine from a faster x2 amd 64 Fedora 8 machine.

[Seve]

Hello :
fakie_flip
What exactly are you trying ?
Are you trying to compile 32bit on a 64bit system etc.?

Effective cross-compiling is not neccesarily that easy do do...

You might want to consider using something like Vmware-server or VirtualBox to install the OS / with the architecture that you want and use that installation to compile the native program.

Just a thought

Seve

[stevea]

I've done a huge amount of cross compiling for embedded linux systems and ... I sort of agree with Seve.

You can build a cross compiler easily enough. Search for the terms "kegel" and "crosstools" and you'll have a nicely scripted cross gnu tool builder. *IF* you are developing your own code and don't need more than a compiler and host make .. then that's pretty good. *BUT* you have to be very careful about making the target code only include and link to the target include files and libraries.


The big headache is that most packages aren't written for cross compilation and the configure script is always trying to peek at the host environment when it should be looking at the target environment. These look at /usr/include or /lib of the host when instead they must look at the target environment. Many of the major packages do work properly, and there have been several partial solutions to this problem ... scratchbox.org for example.

Qemu emulates several target architectures, not just i686 & x86_64 but also PPC, PPC64, Sparc, MIPS, m68k, SH-4 and several others.

[stevea]

Sorry - I went off-topic above. If you just need to recompile a kernel to i686 on a x86_64 machine install an i686 distro under qemu-kvm ( I hope you have the vmx hardware feature). Build the kernel
and move-on.

Also fwiw the crosstools compiler will nicely produce a kernel too, since the kernel has only internal .h dependencies and no library dependencies.


I don't think you'll save as much space as you expect in a trimmed down kernel. You can just delete the excess modules and that's about it. The i686 module tree on Fedora is only 55MB and it only appears on disk (not memory) until you load a module. As a rule you only load modules you need to there is at most a ~54MB disk saving and a tiny memory saving.

The bigger problem are the mammoth libraries associated with KDE and especially Gnome. Big slow memory hogs in recent years. You're using XFCE and still having problems in 64M ! That's bad.


So perhaps you should consider installing distro aimed at a small memory profile.
Not sure but puppylinux and DSL come to mind.

[edit]

Also recompiling XFCE won't help much. You have to attack the Xorg bloat ad that's a big task.

[sideways]

Seve's idea of using a virtual machine would be ideal in this senario, you can even download a ready made fedora vmware image from here (although it would be better to create your own from the fedora install disk using vmware server, that way you ensure all development packages etc are loaded)

I've cross-compiled for arm based systems on a fedora machine using a scratchbox sandbox environment (nice howto here, and a bugfix for fedora) but that is more complicated to set up and unnecessary in this case

[akrao]

how to install pythan

[fakie_flip]

Can I run a 32 bit kernel in Userspace Mode Linux? I think that would work to compile the most effiecient using resouces. VMware will take away a lot of my resources to run it.