[linux-audio-dev] IRQ rotation

Juan Linietsky coding at reduz.com.ar
Sat Mar 6 05:26:17 UTC 2004


On Friday 05 March 2004 16:03, Tim Hockin wrote:
> On Fri, Mar 05, 2004 at 06:30:58PM +0000, Steve Harris wrote:
> > > This really mattered?  I'm honestly DEEPLY surprised, and a bit
> > > sceptical. IRQ priority will only matter AT ALL if you are in a
> > > constant state of interrupt, or your IRQ handlers are painfully slow,
> > > neither of which should be true.
> >
> > Heres /proc/interrupts after ~3 hours of uptime.
> >
> >            CPU0
> >   0:   12578480          XT-PIC  timer
> >   1:      22347          XT-PIC  keyboard
> >   2:          0          XT-PIC  cascade
> >   5:          0          XT-PIC  Maestro3
> >   8:          1          XT-PIC  rtc
> >  10:      58915          XT-PIC  usb-uhci, ohci1394, eth0, Texas
> > Instruments PCI4451 PC card Cardbus Controller, Texas Instruments PCI4451
> > PC card Cardbus Controller (#2)
> >  11:     774663          XT-PIC  nvidia
> >  12:      28909          XT-PIC  PS/2 Mouse
> >  14:      16635          XT-PIC  ide0
> > NMI:          0
> > ERR:          0
> >
> > Everything beats the soundcard, including the video drivers.
>
> It shows that your soundcard had ZERO interrupts.  I have trouble believing
> that over the course of THREE HOURS it tried and tried and could not get a
> single interrupt through.  Is that what you're saying?

The soundcard having zero interrupts seems strange to me..
unless he didnt use it at all?

> This does not show a particularly high interrupt load, either.  It does
> show that you get about 70 video interrupts per second (ask nvidia!) 

That's probably the vblank interrupt, used to sync the contents
of the screen to avoid "paging" effect.. (though doesnt seem
like xfree honors it hehe).. so i guess that can be considered normal too..

reduz








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