Re: Benchmarking on CentOS 5

[Andrea Arcangeli <andrea@qumranet.com>]

On Wed, May 28, 2008 at 10:27:08PM +0200, Farkas Levente wrote:
> ok. so what is qumranet recommendation?

I'm not aware of a Qumranet reccomandation for this but I can give you
my opinion.

> the just released latest rhel 5.2 kernel is kernel-2.6.18-92.el5 is it good 
> enough for kvm host os? or its' better to change some other distro eg: 
> fedora 9?
> until now we try to use the latest rhel/centos on all of our servers while 
> we use fedora (currently 8 but may be upgrade in a few weeks if 9 become 
> stable) on desktops. but now it seems probably then for a kvm host 
> rhel/centos is not enough:-(

This is a almost the opposite question of the previous one from Cam
;), here you're asking about a production kernel, Cam was asking for a
benchmarking setup.

I think any distro enterprise kernel is better for production systems
than a latest mainline, but that's just me. You'll find others
preferring to run 2.6.25 in production a few days after it is
released.

The slowdown we're talking about here for the preempt notifiers isn't
going to make a big difference in a production system, more important
that you're sure your host kernel is rock solid and well tested
IMHO. But if it was pure benchmarking what you were doing, then using
latest mainline was better to get the best possible score, that is why
such printk is there.