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Date:      Sun, 7 Sep 2008 22:54:35 -0700
From:      "Scott Gasch" <scott.gasch@gmail.com>
To:        questions@freebsd.org
Subject:   Re: irq19 uhci interrupts taking ~100% of one core?
Message-ID:  <a174d0600809072254j1ad277e8jdfb638f7e1b71a11@mail.gmail.com>
In-Reply-To: <a174d0600809071607g308a91c0qbc5c114e40c6146e@mail.gmail.com>
References:  <a174d0600809071607g308a91c0qbc5c114e40c6146e@mail.gmail.com>

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Replying to my own question with more data.
Previously I had been running my own kernel; I was curious if the problem
would reproduce with a GENERIC kernel.  It does but the symptoms are
slightly different.  The same irq is firing too often and consuming nearly
all of one core.  But the driver that is associated with the interrupt is
different -- it's fwohci0:

interrupt                          total       rate
irq6: fdc0                             1          0
irq17: mskc0 dc0                  313242         13
irq18: skc0 uhci2*             124475451       5540
irq19: fwohci0+++              957875379      42638
irq23: uhci3 ehci1                  1145          0
cpu0: timer                     44458513       1979
cpu1: timer                     44448875       1978
cpu3: timer                     43393901       1931
cpu2: timer                     43393921       1931
Total                         1258360428      56014


This makes me start to wonder if this is not a problem with irq19 (the PIC?)
and not one particular device / driver.  I'm not sure how to make dig deeper
here, any help greatly appreciated.

Thx,
Scott


On Sun, Sep 7, 2008 at 4:07 PM, Scott Gasch <scott.gasch@gmail.com> wrote:

> Hi,
> I'm running freebsd 7.0-RELEASE-p4 on a 4-core amd64 box.  nearly 100% of 1
> cpu is constantly being used handling irq19: uhci4 interrupts.  This seems
> to happen both with and without any USB devices plugged in:
>
> vmstat -i
> interrupt                          total       rate
> irq1: atkbd0                           5          0
> irq6: fdc0                             1          0
> irq17: mskc0 dc0                 1180547         18
> irq18: skc0 uhci2*             163250699       2512
> irq19: uhci4++                3187989508      49072
> irq23: uhci3 ehci1                    31          0
> cpu0: timer                    129208570       1988
> cpu1: timer                    129208457       1988
> cpu2: timer                    125750147       1935
> cpu3: timer                    125750122       1935
> Total                         3862338087      59452
>
> dmesg
> uhci4: <UHCI (generic) USB controller> port 0xa400-0xa41f irq 19 at device
> 29.1
> on pci0
> uhci4: [GIANT-LOCKED]
> uhci4: [ITHREAD]
>
> Any idea what's going on here and/or how to fix this?
>
> Thx,
> Scott
>
>



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