[linux-audio-user] APIC is bad?

Florin Andrei florin at andrei.myip.org
Thu Jul 15 20:26:41 EDT 2004

I rebuilt the latest Fedora 2 kernel update to enable preempt and
I'm not yet sure about preempt, but IO-APIC has been acting weird.

It gave me more interrupts (up to 21 instead of 15), but the devices
were distributed suboptimal.

Without APIC, the nvidia module was alone on its own interrupt, the
EMU10K1 was alone, the ide and eth modules were on separate interrupts,
etc. Quite ok.

With IO-APIC, nvidia, EMU10K1 and bttv were on the same interrupt, ide2,
ide3 and eth0 were on the same interrupt.
Instead of messing with the kernel again, i just rebooted with the
"noapic" parameter and now the interrupts are looking good again.

BTW, anyone has any measurements on how bad it is to put essential
devices on the same interrupt? (in terms of xruns)

Florin Andrei


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