Re: processes, interrupts, and cpus

[Dan Ritter <dsr@randomstring.org>]

fxkl47BF@protonmail.com wrote: 
> i have a video capture card with 4 separate chips
> when i start up i get bttv0 - bttv3
> i'm getting a lot of errors in syslog on bttv2 and bttv3
> like
> bttv: 2: timeout: drop=3888442 irq=27910652/28054718, risc=338f048c, bits: HSYNC
> bttv: 3: timeout: drop=3940265 irq=27929862/27929862, risc=33adc01c, bits: HSYNC
> 
> could it be related to interrupts and cpus
> cat /proc/interrupts
>       CPU0       CPU1       CPU2  CPU3
> 16:     0   26950435          0     0   IO-APIC   16-fasteoi   bttv1
> 17:     0          0   28079982     0   IO-APIC   17-fasteoi   bttv2
> 18:     0          0   27950635     0   IO-APIC   18-fasteoi   i801_smbus, bttv3
> 19: 66003          0          0     0   IO-APIC   19-fasteoi   bttv0
> 
> i notice bttv2 and bttv3 are on the same cpu
> and bttv3 is sharing an interrupt
> is this related to my timeout errors
> if so is it correctable

Depending on the hardware -- I don't remember the ins and outs
of most video capture cards these days -- you should be able to
set the interrupt per card either in hardware or at kernel
module load time.

This could certainly be an issue, especially on a relatively
low-powered machine; if you don't have the irqbalance daemon
installed, you might try that first.

-dsr-