Re: [BUG] linux-2.6.28-rc3 regression: IRQ smp_affinities not respected

[Eric Dumazet]

Michael Chan a écrit :
> Eric Dumazet wrote:
>
> > Hi all
> >
> > One more problem it seems on 2.6.28-rc3
> >
> > I wanted to get maximal throughput from my machine on a
> > network bench with 3 Gigabit
> > links delivering 600.000 packets per second, so I tried to
> > play with smp_affinity to
> > dedicate one CPU for each NIC.
> >
> > It worked with 2.6.27, so there is a regression on this part.
>
> I believe this may be the patch that broke it:
>
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=ce6fce4295ba727b36fdc73040e444bd1aae64cd
>
> I don't remember all the details, but the Broadcom 5708 chip is
> affected because it does not support MSI per-vector masking.
>
> One way to get around is to disable MSI with bnx2 parameter
> disable_msi=1.

Thanks Michael for your fast answer


I tried this MSI disabling and yes, it now works.

16:      42726        128        105        106         89         89        145        152   IO-APIC-fasteoi   uhci_hcd:usb1, eth0, eth1

But I now have same interrupt used on two NIC, so I cannot split the load on two CPUS, unless
using a smp_affinity with 2 CPUS on it. Not exactly what I wanted to do..

Do you know if BCM5715S (tg3 driver) have same problem ?

03:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (rev 12)
       Subsystem: Hewlett-Packard Company NC373i Integrated Multifunction Gigabit Server Adapter
       Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 16
       Memory at f6000000 (64-bit, non-prefetchable) [size=32M]
       [virtual] Expansion ROM at d1300000 [disabled] [size=16K]
       Capabilities: [40] PCI-X non-bridge device.
       Capabilities: [48] Power Management version 2
       Capabilities: [50] Vital Product Data
       Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-

07:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5708S Gigabit Ethernet (rev 12)
       Subsystem: Hewlett-Packard Company NC373i Integrated Multifunction Gigabit Server Adapter
       Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 16
       Memory at fa000000 (64-bit, non-prefetchable) [size=32M]
       [virtual] Expansion ROM at d1000000 [disabled] [size=16K]
       Capabilities: [40] PCI-X non-bridge device.
       Capabilities: [48] Power Management version 2
       Capabilities: [50] Vital Product Data
       Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/0 Enable-

14:04.0 Ethernet controller: Broadcom Corporation NetXtreme BCM5715S Gigabit Ethernet (rev a3)
       Subsystem: Hewlett-Packard Company NC326m PCIe Dual Port Adapter
       Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 46
       Memory at fdff0000 (64-bit, non-prefetchable) [size=64K]
       Memory at fdfe0000 (64-bit, non-prefetchable) [size=64K]
       [virtual] Expansion ROM at d1200000 [disabled] [size=128K]
       Capabilities: [40] PCI-X non-bridge device.
       Capabilities: [48] Power Management version 2
       Capabilities: [50] Vital Product Data
       Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/3 Enable+

14:04.1 Ethernet controller: Broadcom Corporation NetXtreme BCM5715S Gigabit Ethernet (rev a3)
       Subsystem: Hewlett-Packard Company NC326m PCIe Dual Port Adapter
       Flags: bus master, 66Mhz, medium devsel, latency 64, IRQ 16
       Memory at fdfd0000 (64-bit, non-prefetchable) [size=64K]
       Memory at fdfc0000 (64-bit, non-prefetchable) [size=64K]
       [virtual] Expansion ROM at d1220000 [disabled] [size=128K]
       Capabilities: [40] PCI-X non-bridge device.
       Capabilities: [48] Power Management version 2
       Capabilities: [50] Vital Product Data
       Capabilities: [58] Message Signalled Interrupts: 64bit+ Queue=0/3 Enable-

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