Messages in this thread | | | From | "Khimenko Victor" <> | Date | Thu, 25 Nov 1999 12:46:12 +0300 (MSK) | Subject | Re: SMP kernel with single processor ? |
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In <OF5446ECA7.EAFC68A7-ONCA256834.0007B33E@cvsi.com> Brad.Larden@solution6.com (Brad.Larden@solution6.com) wrote: > Hi All,
> I have what seems like a simple question.
It's not a simple question :-/
> I have a Dell PowerEdge 1300 which has a dual processor motherboard but is > only fitted with one processor and some sort of 'dummy' board in the 2nd > processor slot.
I'm not know about Dell PowerEdge 1300 but I have Dell PowerEdge 2300 with similar configuration and you MUST use SMP kernel there (even when there are in fact just one processor unit installed). Reason ? APIC ... All external PCI devices on Dell PowerEdge 2300 (I almost sure for PowerEdge 1300 this is true as well) are using APIC-extended interrupts (Linux marks them as IRQ 20, IRQ 21, etc). So with UP kernel you simple will be unable to use your hardware.
> Having just installed Redhat 6.1 on the machine I find that it has > installed 2.2.12-20smp by default (yes, I know that's a redhat-ism).
> My question is; Do you see a problem running the smp kernel with a single > processor installed ?
Sometimes it's troublesome (in VERY rare situations: on some rare Cyrix and/or AMD processors mostly), but usually it's just Ok. Slightly slower then UP kernel, though. With PowerEdge you have no choices anyway.
> Excuse my ignorance, I have searched the archives and come up empty on this > subject. > I just have no idea what implications might be in running the smp kernel > and as this machine is going to be a rather well used production squid > server, I don't want it falling in a heap because I 'assumed' everything > would be fine. By the way, the machine won't have a 2nd processor installed > anytime soon.
> Any pointers or comments would be most appreciated.
Check your /proc/interrupts file. If there are APIC interrupts > 15IRQ (last "normal" interrupt) listed as used for something then you have the same situation as I am and SHOULD use SMP kernel.
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