High interrupt CPU usage in top

[Mark Cullen]

Mark Cullen wrote:
Oliver Fromme wrote:

Mark Cullen <mark.r.cullen at xxxxxxxxx> wrote:
 > Taken when the interrupt in top was at 22%, building world:
 >  > 320 total
 > 279 clk
 > 37  fxp0
 > 4   ata1
 >  > Taken when the interrupt in top was at 5%, still building world:
 >  > 288 total
 > 281 clk
 > 7   fxp0
 >     ata1
 >  > Watching it in real-time there are some spikes where either fxp0 
or ata1  > will go up to about ~40-60, but it doesn't really seem to 
relate to the  > number seen in top if you ask me...

All of that looks quite normal.  It certainly shouldn't
account for a significant CPU interrupt percentage.
Either top(1) is lying, or something else is fishy.
Best regards
   Oliver
They were taken with systat as per Danials suggestion by the way, and I 
noticed afterwards it actually shows CPU states like top, slightly 
different from top, probably just due to the different times they were 
started and stuff, but still didn't really seem to relate to the 
relatively high number.

I have noticed that INVARIANTS is in the GENERIC kernel config, might 
that have anything to do with it?
Well, world and kernel just finished compiling, without INVARIANTS, and 
there's no difference. Infact, it seems worse... but it's probably the 
same. I guess I should keep INVARIANTS in for debugging in case of panics?

http://img198.imageshack.us/img198/1571/interrupt3eg.jpg

40% and very few interrupts? That was just starting out compiling 
`mysql4-server`.