compiling the kernel faster

[Daniel Molina Wegener]

   On Thu, Oct 27, 2005 at 05:14:51AM -0700,
   ray at redshift.com wrote:

> At 04:54 AM 10/27/2005 -0700, kamal kc wrote:
> | hello everybody,
> | 
> | i am new to kernel programming.
> | i am developing a compression/decompression
> | functionality in the ip layer.
> | 
> | i want to compile the kernel faster.
> | 
> |  it would
> | be ok if the kernel doesn't have support for sound
> | devices, or other devices like scsi,usb etc. because
> | i would be using the compiled kernel for 
> | network data compression only. 
> | 
> | how could i do that. which source files and where in
> | the makefiles do i make modifications ????
> | 
> | thanks for any suggestions
> | 
> | kamal
> 
> Kamal,
> 
>   The files you modify to drop stuff out of the kernel are in
> /sys/i386/conf/ (assuming you are on an Intel platform). Copy
> the GENERIC file in there to something else (e.g DEVKERNEL),
> then edit that file.

  That's OK, also can take a look into the NOTES kernel config
for additional options.

> Comment out any drivers you don't need using # (check your
> dmesg output when you boot to see what drivers the OS is
> loading for your hardware). Don't comment out anything unless
> it's obviously something you don't need - doublt check the
> dmesg for stuff like network drivers, hard drive stuff, etc.)
> 
> Once you comment out the drivers, you will need to re-compile
> the kernel. Go into /sys/i386/conf/ directory type this:
> 
> config DEVKERNEL (using the example above)
> 
> then change into the directory it shows you (should be
> something like ../compile/DEVKERNEL or something like that)
> and type this:
> 
> make depend && make all install clean
> 
> that will compile the new kernel and leave it in /boot/kernel
> (it will also backup your old kernel into kernel.old)

  Here are new instructions to compile the kernel.

  Go to the root source directory -- usually /usr/src -- then...

  make buildkernel KERNCONF=DEVKERNEL

  But, before making a new kernel, if you add new devices, edit
the src/sys/conf/files to add the device properly.

> go into /boot/kernel/ and type this:
> 
> strip -s *
> 
> then reboot using shutdown -r now

  Nope, if you are developing over the kernel _never_ strip the
symbol table. Do not use the strip command. Instead, use the
kernel config command flag in the DEVKERNEL config file.

makeoptions             DEBUG=-g

  This will enable symbol tables on the kernel for debugging
purposes ;)

> If all goes well, you should boot to the new kernel. You can
> use the uname -a command to make sure you are on the new
> kernel okay. If the machine won't boot, you can boot into
> single user mode and copy the old kernel back in place.
> 
> An excellent book on the subject is:
> 
> Absolute BSD: The Ultimate Guide to FreeBSD (Paperback)
> 
> good luck.
> 
> Ray

  That's OK
  Also take a look on the FreeBSD Documetation Proyect.

Regards.
-- 
 . 0 . | Daniel Molina Wegener
 . . 0 | dmw at unete dot cl
 0 0 0 | FreeBSD Power User