Re: Network problem with 2.6.18-mm1 ?

[ebiederm@xmission.com (Eric W. Biederman)]

"Jesse Brandeburg" <jesse.brandeburg@gmail.com> writes:

> On 9/28/06, Sukadev Bhattiprolu <sukadev@us.ibm.com> wrote:
>> $ cat /proc/interrupts
>>
>>            CPU0       CPU1
>>  28:          0          0   IO-APIC-fasteoi  eth0
>> NMI:         96         35
>> LOC:      18251      18524
>> ERR:          0
>
> you should be getting an interrupt every two seconds from the eth0
> (e1000) driver.  You are having interrupt delivery problems probably
> due to something screwing up interrupt routing in the kernel.
> Normally these issues are associated with MSI interrupts but your
> adapter doesn't support those and is using generic IRQ
>
> I'm guessing that if you somehow enable interrupts on your vga card on
> the same bus as e1000 (bus 3) it will have interrupt delivery problems
> as well.  Maybe try xorg?

To summarize.

We have an e1000 plugged into a pci-x slot on an Opteron system with
an amd chipset.

That motherboard has 3 ioapics.  (One on each PCI-X bridge and
one on the 8111 for handling everything else.

We know we are getting interrupts through the 8111 ioapic.

We don't know which ioapic the pci-x bus is hooked to.

So either the ioapics on the 8131 are having problems.
Or we have a problem parsing the irq routing tables.

We see in dmesg.
[    0.000000] I/O APIC #2 at 0xFEC00000.
[    0.000000] I/O APIC #3 at 0xE8000000.
[    0.000000] I/O APIC #4 at 0xE8001000.
...
[   97.410411] PCI: Cannot allocate resource region 0 of device 0000:00:0a.1
[   97.423945] PCI: Cannot allocate resource region 0 of device 0000:00:0b.1

We see in lspci
> 
> 0000:00:0a.1 PIC: Advanced Micro Devices [AMD] AMD-8131 PCI-X IOAPIC (rev 01)
> (prog-if 10 [IO-APIC])
> 	Subsystem: Advanced Micro Devices [AMD] AMD-8131 PCI-X IOAPIC
> 	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
> Stepping- SERR- FastB2B-
> 	Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
> <TAbort- <MAbort- >SERR- <PERR-
> 	Latency: 0
> 	Region 0: Memory at 88100000 (64-bit, non-prefetchable) [size=4K]
> 
> 0000:00:0b.1 PIC: Advanced Micro Devices [AMD] AMD-8131 PCI-X IOAPIC (rev 01)
> (prog-if 10 [IO-APIC])
> 	Subsystem: Advanced Micro Devices [AMD] AMD-8131 PCI-X IOAPIC
> 	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
> Stepping- SERR- FastB2B-
> 	Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort-
> <TAbort- <MAbort- >SERR- <PERR-
> 	Latency: 0
> 	Region 0: Memory at 88101000 (64-bit, non-prefetchable) [size=4K]

So it looks like the kernel moved the ioapics.

The following patch in 2.6.18-mm1 is known to have that effect.
x86_64-mm-insert-ioapics-and-local-apic-into-resource-map

Can you please try reverting that one patch?

There is a fix an updated version of that patch I think in -mm2
but I haven't had a chance to see if it fixes the problem yet.

Eric
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