Messages in this thread | | | Date | Mon, 8 Sep 2008 21:02:49 +0200 | From | Ingo Molnar <> | Subject | Re: [git pull] x86 fixes |
| |
* H. Peter Anvin <hpa@zytor.com> wrote:
> Arjan van de Ven wrote: >> >> the ideal case would be "support them all" > > Not really. That would include things like the i386, which is a bunch > of really nasty stuff.
agreed - especially the verify_area() impact makes it a non-starter.
but 486 and higher is certainly quite reasonable, and is still being tested.
... and _in practice_ 99% of all systems that run Linux today understand CMOV.
... _and_ in practice 99% of all new Linux systems shipped today are Core2 or better.
... and so on it goes with this argument. Everyone has a different target audience and there's no firm limit. Maybe what makes more sense is to have some sort of time dependency:
support all x86 CPUs released in the last year support all x86 CPUs released in the past 5 years support all x86 CPUs released in the past 10 years support all x86 CPUs released ever [ ... or configure a specific model ]
and people/distributions would use _those_ switches. That means we could continuously tweak those targets, as systems become obsolete and new CPUs arrive.
Ingo
| |