Re: Interrupt storms with wm(4)

[Mouse <mouse%Rodents-Montreal.ORG@localhost>]

> The wm0 interface gets a lot of interrupts.  On low usage, CPU is
> spent around 10% in interrupts.  It can rise to more than 80%.

!!

> Any idea of what could I try to improve the situation?

As a possible data point, I have a machine with six wm interfaces in it
(ifconfig -l reports wm0 wm1 wm2 wm3 wm4 wm5 bge0 lo0 bridge0 tap1
bridge1 tap2 bridge2 tap3 bridge3 tun0 tun1 tun2 srt0 tap0 tap4 tap5)
and it doesn't exhibit anything like that.

It is, however, running much older NetBSD (my 5.2 derivative), and it's
amd64, not i386.  They also are not 82801s:

wm0 at pci1 dev 0 function 0: 82580 1000BaseT Ethernet, rev. 1
wm1 at pci1 dev 0 function 1: 82580 1000BaseT Ethernet, rev. 1
wm2 at pci1 dev 0 function 2: 82580 1000BaseT Ethernet, rev. 1
wm3 at pci1 dev 0 function 3: 82580 1000BaseT Ethernet, rev. 1
wm4 at pci3 dev 1 function 0: Intel i82546GB 1000BASE-T Ethernet, rev. 3
wm5 at pci3 dev 1 function 1: Intel i82546GB 1000BASE-T Ethernet, rev. 3

I mention it in case there _is_ something of use in knowing that older
NetBSD doesn't necessarily do that.  Maybe it's worth trying something
older, maybe even as old as 5.2, just to see if it helps with the
interrupt storms on your hardware?  The 5.2 wm driver does appear to be
prepared to recognize 82801I interfaces.

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