[Asterisk-Users] Re: X100P interrupt load

[Jesse Guardiani]

Kristian Kielhofner wrote:

> Jesse Guardiani wrote:
>> Hello,
>> 
>> Can anyone tell me what the "normal" number of
>> interrupts per second is for an X100P card?
> 
> 1000 / card
> 
>> I've used FreeBSD 5.3 and a linux 2.6.11 kernel
>> on the exact same hardware (only the disk changed)
>> and `systat -vmstat 1` on FreeBSD and
>> `procinfo -dS -n1` under Linux. For both, I'm
>> seeing roughly 1000 interrupts per second on my
>> X100p card. It was a bit worse under FreeBSD,
>> and I experienced frequent lockups, hangs, and
>> X100p malfunctions, so I switched to Linux. The
>> machine is usable under Linux, but I still think
>> that number of interrupts per second is a bit
>> high.
> 
> FreeBSD had some issues with Asterisk.

This should be "has some issues". I do not consider
the FreeBSD zaptel support to be production quality
in any way. I experienced reproducible system hangs
(mostly after an asterisk restart), interrupt issues
(audio skips and SSH pauses during typing), and
general instability. This was with an up-to-date
FreeBSD 5.3-SECURITY and the latest zaptel at
asterisk from ports (1.0.6 for asterisk, and a
significantly lower version for zaptel, I think).

I do not recommend anyone run FreeBSD + Asterisk at
this time.


[...]

> Also, on 2.6.11 look at the "timer" in /proc/interrupts.  It's
> 1000/second too.

Yeah, I saw that. How is that significant? I'm a software guy,
not a hardware guy, so I don't know much about interrupts.
Just that 1000 interrupts/sec is fairly high. :)


>> My motherboard is an Abit BE6, and it seems to
>> have some IRQ assignment problems, so I'm
>> wondering what my baseline should be.
>> 
>> Also, I have a dual CPU PII motherboard with two
>> X100P cards in it, and it's hitting about 1000
>> interrupts per second per card too. Is this normal?
>> How many interrupts per second can a given CPU
>> sustain?
> 
> If you want to reduce interrupt load, go down to one card.  If you have
> 4 X100P's, that 4000 interrupts/sec.  If you have 1 TDM400, that's
> 1000/sec.

Again, is there a formula to describe how many interrupts per
second a given CPU, PCI bus, and FSB bus can theoretically
sustain per second?

I'm curious if my 450mhz PIII should be able to handle 2 x100p
cards, or just 1? What's the limit? Etc....

-- 
Jesse Guardiani, Systems Administrator
WingNET Internet Services,
P.O. Box 2605 // Cleveland, TN 37320-2605
423-559-LINK (v)  423-559-5145 (f)
http://www.wingnet.net