[lug] Clock drifting - SOLVED

[D. Stimits]

Zan Lynx wrote:
> On Wed, 2006-03-29 at 08:19 -0700, John Hernandez wrote:
> 
>>I solved the problem by booting with the kernel option 'noapic'.  Thanks
>>to the previous responders for helping get my investigation on track.
>>
>>I'm curious:  What is apic, and what's the tradoff of running 'noapic'?
>> My processor is an Athlon XP 2700+, kernel 2.6.12, if it matters.

Incidentally, there are both SMP APICs, and non-SMP APIC's. On the SMP 
boards (multiple cpu), the APIC is required if any cpu other than cpu #0 
is to service hardware interrupts. This can actually be quite a boost to 
how smooth the system feels under load, especially if you are running 
simultaneous network and disk loads. Software interrupts can be handled 
on any cpu, even if APIC is disabled, but software interrupts are a bad 
way to manage hardware drivers (very high overhead). Software interrupts 
work fine for programs which don't require kernel access to hardware.

D. Stimits, stimits AT comcast DOT net