Thanks for your info, but your message leaves open exactly the two
questions that I was asking:
On Wed, 2009-08-26 at 12:15 -0700, Rick Stevens wrote:
Jonathan Ryshpan wrote:
> Configuring the kernel I came across a choice between generic-x86_64
> processors, and the Opteron/Athlon/Hammer/K8 processors. My system has
> a 4-core Phenom processor. Questions:
>
> 1. Is the Phenom compatible with the Opteron/etc? I.e. if I
> configure for the Opteron, will my kernel be reliable? (This is
> not as easy to find out as I thought.)
To my knowledge, yes. It's certainly compatible with the Athlon. I run
a Phenom quad-core as well, but I just use the off-the-shelf x86_64
kernel. Works fine.
I run the same kernel myself, built for the generic-x86_64 CPU. The
question is are there enhancements for the Athlon above the generic,
which are not compatible with the Phenom. I think not, but I haven't
been able to get any firm info yet.
> 2. How much of a performance advantage is there to
configuring for
> the Opteron as against the generic?
I don't know that you'd notice any significant difference with a normal
work load. If you were doing heavy I/O or number crunching, then you
might see some difference, but not enough to really bother making a
custom kernel.
Again, I suspect you're right about both things. I have to build
another kernel to chenge the preemption rule from VOLUNTARY_PREEMPT to
PREEMPT, so this looked like a natural change to add (if it works).
Thanks - jon