Re: [2.6.36.1] IGB driver handles all ethX interrupts on single cpu core.

[PaweÅ Sikora]

On Wednesday 08 of December 2010 02:44:25 Robert Hancock wrote:
> On 12/07/2010 12:06 PM, PaweÅ Sikora wrote:
> > hi,
> >
> > i'm currently testing a new server with 2x opteron-6128 with dual gigabit port
> > and observing that the igb driver uses only single core for all ethX interrupts.
> > is it a correct behaviour for this driver?
> >
> > BR,
> > Pawel.
> 
> The CPU affinity for the IRQ isn't really under the driver's control. It 
> looks like all your interrupts are being handled on CPU0. You likely 
> need to run the irqbalance daemon.

ok, so why e.g. on one machine (dual amd opteron) irqbalance daemon is required
and on second machine (single intel quad-core) irqs are balanced w/o daemon?
this looks inconsistent to me.

$ cat /proc/interrupts
           CPU0       CPU1       CPU2       CPU3
  0:         49          2          0          0   IO-APIC-edge      timer
  1:          0          1          0          1   IO-APIC-edge      i8042
  8:         13         11         12         13   IO-APIC-edge      rtc0
  9:          0          0          0          0   IO-APIC-fasteoi   acpi
 12:          0          0          3          1   IO-APIC-edge      i8042
 16:        224        236        235        232   IO-APIC-fasteoi   pata_marvell, uhci_hcd:usb3
 17:          0          0          0          0   IO-APIC-fasteoi   saa7133[0], saa7133[0]
 18:          0          0          0          0   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb5, uhci_hcd:usb8
 19:        695        672        660        630   IO-APIC-fasteoi   uhci_hcd:usb7
 21:          0          0          0          0   IO-APIC-fasteoi   uhci_hcd:usb4
 23:          1          1          1          0   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb6
 40:       3409       3446       3441       3403   PCI-MSI-edge      ahci
 41:         63         60         60         61   PCI-MSI-edge      hda_intel
 42:       3219       3180       3237       3192   PCI-MSI-edge      radeon
 43:        505        487        496        498   PCI-MSI-edge      eth0
NMI:         11          7         12          8   Non-maskable interrupts
LOC:      14822      15293      17577      14404   Local timer interrupts
SPU:          0          0          0          0   Spurious interrupts
PMI:         11          7         12          8   Performance monitoring interrupts
PND:          0          0          0          0   Performance pending work
RES:        493        498        525        495   Rescheduling interrupts
CAL:       3975        248       2729        299   Function call interrupts
TLB:        937       1727        913       1600   TLB shootdowns
TRM:          0          0          0          0   Thermal event interrupts
THR:          0          0          0          0   Threshold APIC interrupts
MCE:          0          0          0          0   Machine check exceptions
MCP:          2          2          2          2   Machine check polls
ERR:          3
MIS:          0
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