Kernel upgrade: Is it worth it?

[lucho]

The title says it all. I´m running both Debian Etch and Ubuntu Breezy
on my machine. I compiled a new kernel on Breezy (from 2.6.12-10-amd64-k8
to 2.6.16.16), and got a nice increase in performance.
I´m running a 2.6.15-1-k7 kernel from the repositories on Etch, and things
work very nicely. So here´s my question: I´ve got the source material for
a 2.6.16.16 or 2.6.16.20 kernel, but is it worth it to compile a new kernel?
Or should I stick with what I have?
Opinions?

[Javasnob]

Is it worth it?

Of course.

What does it cost you to compile a new kernel? 5-10 minutes of configuration and around 30 minutes to compile while you go watch TV, take a nap, make a sandwich, etc. So practically nothing. It's not like you can't go back to your old kernel if the new one fails; just have another GRUB/LILO entry for it.

[antidrugue]

As Javasnob said, it is very much worth it, specially if you have relatively new hardware, or are using drivers which development are fast paced (wireless, power management, etc.).

Remember to configure it right (for example : turn off kernel hacking, choose low-latency, high frequency timer, etc.) so it suits your machine.

[lucho]

thanks for the advice. I guess what I´m after is if I can expect any
kind of boost in performance. My hardware isn´t so bleeding edge,
but the old kernel handles all of it like a champ.
Ok, it´s very late here, so I´ll get down to business tomorrow. In
Ubuntu, I just removed all the drivers not related to my hardware,
went for low-latency and high-frequency timer (I turned off the kernel
hacking, but because it was recomended. What does it do?). Is that
how it´s supposed to be configured?

[antidrugue]

I turned off the kernel
hacking, but because it was recomended. What does it do?

Kernel hacking has to do with debugging, it is mainly useful for kernel and drivers developpers (for more info, see the "help" about kernel hacking in "make menuconfig").

I would say try the Con Kolivas patches to the Linux kernel if you want a nice performance boost :
http://members.optusnet.com.au/ckolivas/kernel/

There is an how-to here :
http://ck.kolivas.org/faqs/walkthrough.txt

But it is pretty simple, you just patch the kernel :

cd /usr/src
tar jxf /path/to/linux-2.6.17.bz2
mv linux-2.6.17 linux-2.6.17-ck1
cd linux-2.6.17-ck1
bzcat /path/to/patch-2.6.17-ck1.bz2 | patch -p1

And then you go on with the rest.

Remember that those "ck" patches are to be applied to unpatched kernel sources, like 2.6.15, 2.6.16, 2.6.17. And not to 2.6.15.7 or 2.6.16.20. They already contain the latest fixes.

[lucho]

Ok, I finally got some time to compile a new kernel. I used the
2.6.16.20 source, and simply recycled my old kernel config- I only
changed things like latency and kernel hacking. It´s interesting, the
debian kernel is already set to a frequency of 1000mhz, while the
ubuntu one is set to 250mhz- now I know why Debian is always faster
than Ubuntu.
So anyway, there is a bit of a boost in performance; things are starting
up a little bit faster. But memory usage has gone up: it was 94-135 MB
before, but now it´s in the 145-225MB range
I guess a little more memory is worth it for the extra horsepower. I already
like this new kernel. Gotta love Debian