[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: is it em64t ?

On Saturday 07 January 2006 11:46, Hamish Moffatt wrote:
> It does, but what if HyperThreading was present but disabled in the
> BIOS? I don't know how you would tell in that case.

Most of these flags are not set simply because the kernel found a certain type 
of processor. They are the result of elaborate startup tests which detect 
these capabilities. 

If a capability is disabled in the bios, two things can happen

1) the kernel does not detect it at all; in which case the relevant flag is 
not set;

2) the kernel detects the capability but switched off; in which case the 
kernel will attempt to switch it on (if it can of course). If this succeeds 
the flag is set, if not you will often see an error and the flag is not 
switched on.

I have been told, however, that a few processor capabilities are so bound to 
the a certain type of cpu that their flag is simply set if that cpu is found.

I don't know under which category the hyperthreading flag falls, but knowing 
that hyperthreading can be disabled in the bios, I would not expect the 
kernel to simply set that flag blindly.


Reply to: