Subject: Re: [linux-audio-dev] IRQ rotation
From: Tim Hockin (thockin_AT_hockin.org)
Date: Fri Mar 05 2004 - 21:03:46 EET
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?
This does not show a particularly high interrupt load, either. It does show
that you get about 70 video interrupts per second (ask nvidia!) and it shows
that you seem to have the timer at 1024 HZ (lowlatency patch?).
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