Re: processes, interrupts, and cpus
On Tue, 20 Aug 2024, Dan Ritter wrote:
> 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-
>
i installed irqbalance and it dramatically reduced the errors
from 2-3 a minute to 1 every 3-4 minutes
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