Re: [Qemu-devel] [PATCH] Add definitions for current cpu models..

[Anthony Liguori]

On 01/26/2010 02:26 AM, Gerd Hoffmann wrote:
> On 01/25/10 23:35, Dor Laor wrote:
> > On 01/25/2010 04:21 PM, Anthony Liguori wrote:
> > > Another way to look at this is that implementing a somewhat arbitrary
> > > policy within QEMU's .c files is something we should try to avoid.
> > > Implementing arbitrary policy in our default config file is a fine 
> > > thing
> > > to do. Default configs are suggested configurations that are modifiable
> > > by a user. Something baked into QEMU is something that ought to work 
> > > for
> >
> > If we get the models right, users and mgmt stacks won't need to define
> > them. It seems like almost impossible task for us, mgmt stack/users
> > won't do a better job, the opposite I guess. The configs are great, I
> > have no argument against them, my case is that if we can pin down some
> > definitions, its better live in the code, like the above models.
> > It might even help to get the same cpus across the various vendors,
> > otherwise we might end up with IBM's core2duo, RH's core2duo, Suse's,..
>
> I agree.  When looking at this thread and config file idea it feels a 
> bit like "we have a hard time to agree on some sensible default cpu 
> types, so lets make this configurable so we don't have to".  Which is 
> a bad thing IMHO.

There's no sensible default.  If a user only has Nehalem-EX class 
processors and Westmeres, why would they want to limit themselves to 
just Nehalem?  For an organization that already uses and understand the 
VMware grouping, is it wrong for them to want to just use VMware-style 
grouping?

This feature is purely data driven.  There is no code involved.  Any 
time a feature is purely data driven and there isn't a clear right and 
wrong solution, a configuration file is a natural solution IMHO.

I think the only real question is whether it belongs in the default 
config or a dedicated configuration file but honestly that's just a 
statement of convention.

Regards,

Anthony Liguori

> cheers,
>   Gerd