Weird system cpu usage
danger at FreeBSD.org
Wed Mar 19 14:08:36 PDT 2008
Wednesday, March 19, 2008, 9:32:13 PM, you wrote:
>>Also, I believe there was a report from another user who saw similar
>>issues with em(4), and found that disabling MSI fixed the storm in
>>question. I believe you can disable MSI/MSIX by placing the following
>>in /boot/loader.conf, then reboot:
> When MSI is enabled, the irq will be a strangely high number. e.g.
Interesting, I have disabled MSI and MSIX support, but they still share
the same irq. However, I don't know yet if the interrupt storm is
going to be resolved, it needs some time (It always used to take some
time until it has showed up).
> If anything, I found enabling MSI helped matters where I saw strange
> IRQ issues. However, not sure if the original poster's hardware
> supports it. One thing it does remind me of is some strange IRQ
> issues I had on an AMD board where a USB setting for "legacy handoff"
> (something like that) would really slow down the machine with an in
> inordinate amount of IRQs firing. I forget if I had to enable it or
> disable it to fix the problem. If anything, I would try disabling
> USB all together if its not being used even though its not figuring
> in the above really high rate of IRQs.
The USB isn't indeed used, I will think about disabling it, and also
about trying to move around the em(4) NICs to the other slots.
Unfortunately I don't have a physical access to the given maschine.
Daniel mailto:danger at FreeBSD.org
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