Why is em nic generating interrupts?

Michael O. Boev mike at tric.tomsk.gov.ru
Mon Oct 6 05:49:06 PDT 2003


Hello, everyone!

I've got a [uniprocessor] router machine with fxp and em nics.
I've built my kernel with the following included:

options         DEVICE_POLLING
options         HZ=2500

and enabled polling in /etc/sysctl.conf.

Having looked through a vmstat -i output I see
that the em card is generating interrupts, although
they should be disabled (as I see in em's source code).

interrupt                     total       rate
stray irq0                        1          0
stray irq6                        1          0
npx0 irq13                        1          0
ata0 irq14                     2339          0
em0 irq10                    421457        155
fxp0 irq5                         2          0
atkbd0 irq1                    3326          1
clk irq0                    6778872       2500
rtc irq8                     346899        127
Total                       7552898       2786

What's happening? Is polling working in my case?
If yes, why is vmstat showing interrupts? I see clearly,
that fxp's counter doesn't increase, and em's is constantly growing.

Thanks in advance to anyone for an idea!
Please also CC: me as I'm not subscribed.
--
Best wishes,
[mike at tric.tomsk.gov.ru].


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