'top' showing high interrupt rate

[Andy Farkas]

On Wed, 21 May 2003, Paul Hamilton wrote:

> I noticed that top shows a rather high interrupt rate, usually hovering
> around 60%!  Here is a sample:-

Try `top -S` instead. This will show system processes as well. Also, use
`systat -v` as previously mentioned to see interrupt counts.

> last pid:  2879;  load averages:  0.34,  0.24,  0.18
> up 1+17:26:56  17:18:10
> 36 processes:  2 running, 33 sleeping, 1 zombie

Zombies not good.

> dmesg says:
>
> Copyright (c) 1992-2000 The FreeBSD Project.
> Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
>         The Regents of the University of California. All rights reserved.
> FreeBSD 4.2-RELEASE #1: Tue Feb 13 22:51:23 WST 2001
>     root at ant.compwest.net.au:/usr/src/sys/compile/ANT
> Timecounter "i8254"  frequency 1193182 Hz
> CPU: Pentium/P55C (165.79-MHz 586-class CPU)
>   Origin = "GenuineIntel"  Id = 0x544  Stepping = 4
>   Features=0x8001bf<FPU,VME,DE,PSE,TSC,MSR,MCE,CX8,MMX>
> real memory  = 33554432 (32768K bytes)
> avail memory = 29478912 (28788K bytes)
>
> Yes, the server only has 32MB or RAM, however, it's only using 4MB of VM.
>
> Anyone have any idea how to troubleshoot further?  How can I isolate what is
> causing the rather high interrupt rate?

My guess is this box is a gateway/firewall and may be getting pounded on
the network interfaces. Are you running ipfw as well?

--

 :{ andyf at speednet.com.au

        Andy Farkas
    System Administrator
   Speednet Communications
 http://www.speednet.com.au/