Re: High interrupt CPU usage in top

[Danial Thom <danial_thom@xxxxxxxxx>]

--- Mark Cullen <mark.r.cullen@xxxxxxxxx> wrote:

> Oliver Fromme wrote:
> > Mark Cullen <mark.r.cullen@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?
> 

I just made mysql on a 4.9 Freebsd box and I get
50-80% interrupt usage. Its probably long disk
stop-and-waits or something. I'd guess its
nothing unusual.

DT

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