performance issues without apic?

roan · n00b Joined: 11 Jul 2002 Posts: 22

I can't boot without the noapic boot option. How much of an issue is this
when it comes to performance? I have a Fujutsi/Siemens RX200 with
a 2.8 GHz XEON processor and 2G RAM (chipset is Intel 7501 if this can
be of any interest). It is a 2 processor motherboard but currently I only
have one processor.

If I understand the little information I've seen about APIC right
(which I probably haven't) this means the processor will not use so
called hyperthreading. Is this correct? Is there anyway for me to fix
this without becoming a kernel hacker? Should it be reported to
someone or is it a known issue?

Best regards
Robert Andersson

oggialli · Posted: Tue Oct 12, 2004 8:31 am Post subject:

Dunno if it affects HT, but youll at least lose interrupts, and I think if you upgrade to 2 CPU's the standard 15 IRQ lines won't be enough (or thats what APIC does on uniprocessor systems at least)

I doubt it will affect performance directly if you don't lose HT that is.
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IBM Thinkpad T42P - Gentoo Linux

burzmali · Apprentice Joined: 18 Apr 2002 Posts: 238 Location: ca

i beleive you have to configure your kernel for smp and ht support to have hyperthreading work, and with those options selcted, the apic option goes away from the config menu (right?). cat out /proc/cpuinfo, if it shows two cpus then you are all set, if not, go back and make sure you have smp enabled in your kernel.

good luck.
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burzmali
www.burzmali.net