Dell Vostro 200: Interrupts



  • I sincerely apologize if this has been covered elsewhere.

    I've got a Dell Vostro 200 that I'm planning on using for pfSense. Everything seems to be working smoothly. My only concern is that the system is continually running at a load average of 1, even with no load on it. Looking at top, I see that the CPU is busy dealing with interrupts.

    
    last pid: 67336;  load averages:  1.00,  1.00,  1.00                    up 0+13:42:24  03:46:33
    80 processes:  4 running, 59 sleeping, 17 waiting
    CPU states:  0.0% user,  0.0% nice,  0.2% system, 41.7% interrupt, 58.1% idle
    
    

    (This is a dual-core processor, so it appears that one of the cores is busy handling interrupts.)

    If I look at vmstat -i, I see:

    
    interrupt                          total       rate
    irq16: skc0 uhci0                   2371          0
    irq18: ehci0 uhci5                     2          0
    irq19: uhci2 uhci*            2585067329      52370
    irq21: uhci1                           1          0
    cpu0: timer                     98676946       1999
    cpu1: timer                     98676389       1999
    Total                         2782423038      56368
    
    

    I'm really not sure how to go about debugging this problem. Any advice would be appreciated.



  • An update…

    The BIOS in this system has a setting that controls the SATA controller's mode... It can be toggled between "IDE" and "RAID". By default the system was configured in "IDE" mode--the controller showed up as a generic ATA controller under FreeBSD.

    Tonight I switched the controller to "RAID" mode. Now it shows up as an Intel ICH8 SATA300 controller. The high interrupts have disappeared and everything seems to be working well.

    The only catch is that the system doesn't appear to detect the SATA DVD-ROM any longer. This isn't a show-stopper as I'm only using it during the initial installation. I can probably toggle the controller configuration for that purpose.

    Maybe the DVD-ROM will reappear in the future with a 7.x FreeBSD kernel?



  • I think the Dell systems which allow RAID see Sata0 and Sata1 as members of RAID.  If you have another Sata port ie…Sata2 try switching the CD-ROM to that port.  I know this is true with the Dell 755's.

    Mark


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