On Fri, 7 Jan 2005 22:12:00 +0100, Andi Kleen wrote:
>On Fri, Jan 07, 2005 at 01:14:24PM -0800, YhLu wrote:
>> After keep the bsp using 0, the jiffies works well. Werid?
>
>Probably a bug somewhere. But since BSP should be always
>0 I'm not sure it is worth tracking down.
I hope by "0" you're referring to a Linux kernel defined
software value and _not_ what the HW or BIOS conjured up!
Case in point: I was involved a while ago in tracking down
and fixing a local APIC enumeration bug in the x86-32 (i386)
kernel code, where the kernel failed miserably on some
dual K7 boxes because (a) only one CPU socket was populated,
(b) the BIOS assigned that CPU a non-zero ID, and (c) the
kernel (apic.c) had a bug which triggered when BSP ID != 0.
Never trust a BIOS to DTRT.
/Mikael
On Sat, Jan 08, 2005 at 03:37:50AM +0100, Mikael Pettersson wrote:
> On Fri, 7 Jan 2005 22:12:00 +0100, Andi Kleen wrote:
> >On Fri, Jan 07, 2005 at 01:14:24PM -0800, YhLu wrote:
> >> After keep the bsp using 0, the jiffies works well. Werid?
> >
> >Probably a bug somewhere. But since BSP should be always
> >0 I'm not sure it is worth tracking down.
>
> I hope by "0" you're referring to a Linux kernel defined
> software value and _not_ what the HW or BIOS conjured up!
No, I'm refering to the APIC ID configured by the BIOS.
> Never trust a BIOS to DTRT.
I won't complicate the x86-64 code to work around non existant
theoretical BIOS issues.
-Andi