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SubjectRe: emu10k1 - interrupt storm?
On 9 Dec 2001, Zlatko Calusic wrote:

The emu10k1 only generates interrupts when playing pcm sound.
The interrupt rate depends on the "fragment" size and is usually
smaller than ~1000interrupts/s (this is 256bytes fragment 48Khz sample
rate, 16bit, stereo).

Is it possible there is another device producing these interrupts?
On-board devices (usb, ...) that you don't use?
Does this happen with this kernel only?

> Rui Sousa <rui.p.m.sousa@clix.pt> writes:
> >
> > The current emu10k1 driver uses a hardware clock to generate periodic
> > interrupts. These apparently ran at the wrong rate in some Alpha machines.
> > It's possible that the same problem occur now with more recent i386
> > machines.
> >
>
> Hi!
>
> Sorry to quote a really old email. :)
>
> I'm currently investigating why is my emu10k1 doing so much
> interrupts. They are so frequent that they usually show on a kernel
> profile report on the top, no matter what I've been doing with the

Which functions do you see listed? If it's only "emu10k1_interrupt()"
then the interrupt was not generated by the emu10k1.

> poor machine (interrupts are there even if I'm not using my
> Soundblaster live).
>
> Kernel is the most recent 2.5.x. dmesg says:
>
> Creative EMU10K1 PCI Audio Driver, version 0.16, 16:17:32 Dec 9 2001
> emu10k1: EMU10K1 rev 6 model 0x8027 found, IO at 0xc400-0xc41f, IRQ 10
> ac97_codec: AC97 Audio codec, id: 0x8384:0x7609 (SigmaTel STAC9721/23)
>
> This is my /proc/interrupts:
>
> CPU0 CPU1
> 0: 423348 425806 IO-APIC-edge timer
> 1: 13674 13371 IO-APIC-edge keyboard
> 2: 0 0 XT-PIC cascade
> 8: 2 1 IO-APIC-edge rtc
> 10: 5956299 5956064 IO-APIC-level EMU10K1 <===========
> 11: 19803 20033 IO-APIC-level ide2
> 12: 104203 101822 IO-APIC-edge PS/2 Mouse
> 14: 4356 4285 IO-APIC-edge ide0
> 15: 7 9 IO-APIC-edge ide1
> NMI: 0 0
> LOC: 849167 849165
> ERR: 2
> MIS: 0
>
> Yes, this is a SMP machine, but I don't know why would that make any
> difference. As you can see, number of emu10k1 interrupts is enormous
> (I also tried noapic, no changes).
>
> procinfo -d quickly shows that emu10k1 is generating ~1412 interrupts
> per second (7060/2).
>
> irq 0: 500 timer irq 10: 7060 EMU10K1
> irq 1: 1 keyboard irq 11: 10 ide2
> irq 2: 0 cascade [4] irq 12: 164 PS/2 Mouse
> irq 3: 0 irq 14: 2 ide0
> irq 4: 0 irq 15: 0 ide1
> irq 8: 0 rtc
>
> Is that the periodic hardware interrupt you're talking about, and why
> are there so many interrupts? Is there a way to stop that storm?
>
> Regards,
>

Rui Sousa

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