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Re: Success - finally



On Mon, 20 Jul 2009 08:20:20 -0700
Markus Kesaromous <remotestar live com> wrote:
> >
> > Bradley,
> >
> > On Mon, Jul 20, 2009 at 5:44 AM, Bradley wrote:
> >> Well, I've been tinkering with installing an optimized kernel for
> >> years and finally I understand how to do it! This was such a big
> >> thing for me, since I run on an older, slower system, that I had
> >> to share it. I am now running Kernel 2.6.30.1 on my system and it
> >> runs so much nicer than before. I still have some optimization to
> >> do on it but getting it to this point was a major accomplishment
> >> for me.
> >>
> >
> > Congratulations!
> >
> > I'd be interested in hearing/reading what you did to optimize. What
> > did you modify/change in the config file? Which command did you use
> > to modify the config file.
> >
> > I have an older system too - VA Linux 420 that I purchased in 2000,
> > VA Linux Systems was making and selling computers.
> >
> > Thank you for your consideration,
> > Darlene Wallach
> >
> 
> I to would like to know how you optimized the kernel to run better
> (i.e. less cpu utilisation). I am on an older machine as well, and
> currently running F11. Everything is so sluggish now. 
> 
> MM

The Fedora instructions for building a custom kernel are here:

http://fedoraproject.org/wiki/Building_a_custom_kernel

Doing a web search will turn up other instructions as well, to give you
a cross reference if you need it for clarification.

If you have an old system, then you can immediately eliminate the
virtualization stuff.  It won't have the hardware support and if you
run the software version it will be too slow.  And SMP if you have
a single cpu (the menuconfig says this speeds up the cpu slightly).
The kernel hacking section is a great place to eliminate lots of things
unnecessary unless you are developing the kernel.  Switch off
optimizing for size as that will enable optimizing for speed (at least
that is what menuconfig says). Because you are eliminating so much stuff
from the kernel, it will be smaller anyhow, so page swapping isn't such
a big issue.  In network, you can get rid of all the Gigabit and picabit
cards. Firewire and lots of the scsi can go too.  If you are not on a
network, eliminate all the network filesystems.  Do you use exotic
filesystems? Eliminate all but the actual filesystem you use.
Shouldn't need all the alsa sound card modules.  Don't have any flash
devices, eliminate flash support. It is slow, but just use the help
function on every option, and decide if you need it.

Eliminating modules doesn't really change the size of the kernel,
because they are loaded only if needed.  But they sure take a lot of
time to compile every time, so get rid of them if they aren't
necessary.  And eliminating entire subsystems of modules does shrink the
kernel because you no longer need the code to support the modules.

I don't know that the following is true, just seems logical. If there
is something you *know* you have and use, build it into the kernel, not
as a module.  Calling a module is an extra call through the module
interface and will slow down the usage. For occasional usage, not an
issue, for continuous use will have an impact.

Boot device support has to be built into the kernel so it can find
and use the device to boot from.  So don't make it a module or
eliminate it.

Build, install, reboot, and try often.  Save the config files along the
way, or at least the last working config.  That way when you eliminate
something that is needed, you can immediately go back to the last
working config and start from there again.

Remember, if you get new hardware that you aren't supporting in your
custom kernel, you can always drop back to the Fedora generic kernel to
test it, or rebuild your custom kernel to include support.  So be
ruthless.

As far as speed goes, there are lots of background processes that run
continuously.  Removing beagle, strigi, locate/updatedb, prelink can
make your system seem faster because they aren't sucking cycles.  Linux
seems to be going the luxury car route, putting all kinds of exotic
functionality in place.  On a modern system, it is hardly noticeable,
on an older system it has an impact.  Use top to find these.

Add memory, the simplest way to improve performance.  Max it out.



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