Re: emu10k1 - interrupt storm?

[Rui Sousa]

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 <[e-mail]> 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