illegal instruction - create compile variants ?

[David Timms]

On 01/05/11 17:41, Hans de Goede wrote:
> Erm, specifying a minimum support CPU in the package description is
> not acceptable IMHO. The fix here is to patch the packages buildsystem,
> so that it gets build for the minimum cpu level which is supported by
> Fedora, and thus will work out of the box on all systems Fedora
> supports.
Where is that stated currently, and for older releases ?

> No tricks / hacks with multiple compilation, cpu detect scripts, etc.
> will be necessary then.
Though it comes at the cost of audio lag/latency increase when we are 
trying to achieve near real time (eg live guitar input to sound effect 
generation output). Even on the my machine (4x core amd 3Ghz), the 
calculations the app performs for difficult presets (convolution) can 
cause jack to abort because rakarrack didn't finish it's calculations 
before it was required to deliver data.

Should I be suggesting to upstream to attempt to detect CPU before 
running non-available instructions, eg as part of app startup ?
Can that even be done (reliably) ?

Thanks for your input.