Re: Interrupt storm with MSI in combination with em1

Who makes your motherboard? The problem you are having is that MSIX AND
MSI are both failing as em0 comes up, so it falls back to Legacy interrupt
mode,
and must be having some issue with sharing the line, causing the storm.

This is the second report in a matter of a week perhaps about a problematic
motherboard, I would like to know who makes them.

Thanks,

Jack


On Wed, May 4, 2011 at 8:34 AM, Daan Vreeken <Daan_at_vehosting.nl> wrote:

> Hi All,
>
> I've just updated a machine to -current (r221321) and since then I'm seeing
> an
> interrupt storm on irq 16. The storm goes away when I disable MSI/MSIX with
> the following lines in "loader.conf" :
>
>        hw.pci.enable_msix="0"
>        hw.pci.enable_msi="0"
>
> According to "dmesg" the following devices share IRQ 16 :
>
>        pcib1: <ACPI PCI-PCI bridge> irq 16 at device 1.0 on pci0
>        em0: <Intel(R) PRO/1000 Network Connection 7.2.3> port 0xcc00-0xcc1f
>           mem
> 0xf7de0000-0xf7dfffff,0xf7d00000-0xf7d7ffff,0xf7ddc000-0xf7ddffff
>           irq 16 at device 0.0 on pci1
>        vgapci0: <VGA-compatible display> port 0xbc00-0xbc07
>           mem 0xf7800000-0xf7bfffff,0xe0000000-0xefffffff irq 16 at device
> 2.0 on
>           pci0
>        ehci0: <Intel PCH USB 2.0 controller USB-B> mem
> 0xf7cfa000-0xf7cfa3ff
>           irq 16 at device 26.0 on pci0
>        em1: <Intel(R) PRO/1000 Network Connection 7.2.3> port 0xec00-0xec1f
>           mem
> 0xf7fe0000-0xf7ffffff,0xf7f00000-0xf7f7ffff,0xf7fdc000-0xf7fdffff
>           irq 16 at device 0.0 on pci4
>        pcib4: <ACPI PCI-PCI bridge> irq 16 at device 28.5 on pci0
>
> During a storm "vmstat -i" shows a rate of about 220.000 interrupts/sec.
> MSI
> interrupt delivery to both 'em0' and 'em1' seems to work correctly during a
> storm, as I see their counters increase normally in the "vmstat -i" output.
>
> As only 'em0' and 'em1' seem to be using MSI interrupts, my guess is that
> the
> e1000 driver is causing this problem. Could it be that the driver forgets
> to
> clear/mask legacy interrupts when attaching the MSI interrupts perhaps?
>
> Any tips on how to debug and/or fix this?
>
>
> The full output of "dmesg" can be found here :
>        http://vehosting.nl/pub_diffs/dmesg_plantje2_2011_05_04.txt
>
> And the full output of "pciconf -lv" is here :
>        http://vehosting.nl/pub_diffs/pciconf_plantje2_2011_05_04.txt
>
>
> Regards,
> --
> Daan Vreeken
> VEHosting
> http://VEHosting.nl
> tel: +31-(0)40-7113050 / +31-(0)6-46210825
> KvK nr: 17174380
>