Irq high cpu usage

  • Hello All,


    On one of our two pfsense boxes being used in a k-12 school setting which is a fairly old VIA processor decommisioned commerical router , after several days of uptime ,currently 70 days uptime ,the IRQ is very high cpu usage on two irq's. Does anyone know how to circumvent this? I done a search here first and did not get any exact results for this.
    I will attach a  copy/paste of  top -S :   below,

    Edit:I should have added , for completeness, the two IRQ's that show high cpu count are IRQ 10 for the two onboard nics , and IRQ 11 which is a GB add on card.

    thank you,


  • Netgate Administrator

    Running that comand from the console rather than via the GUI will give CPU figures as well.
    While you're there run vmstat -i:

    [2.0-RC3][]/root(4): vmstat -i
    interrupt                          total       rate
    irq4: uart0                          852          0
    irq14: ata0                       192437          0
    irq16: fxp3 uhci0                      1          0
    irq17: fxp2 fxp6                22384728         11
    irq18: em0 ath0++              114952354         57
    irq19: fxp0 fxp4+                5543477          2
    irq23: ehci0                           1          0
    irq26: em1                      15201802          7
    irq27: em2                       1763446          0
    cpu0: timer                    798574991        400
    Total                          958614089        480


  • Sounds like a hardware issue.

    A trick that might help is to disconnect power supply units, open up the server, and take out the bios battery, which will essentially perform a full bios reset and clear up anything wierd going on.

    It will also give you an opportunity what the physical state of that server is like.

  • Just a matter of a slow CPU, crappy NICs, and too much throughput for those two things. Replacing the Realtek NICs with good ones would reduce that, though you may just be trying to do more with a slow CPU than is reasonable and need a faster one (depends on how much traffic you're pushing and what kind of CPU that is).

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