Re: cpu load balancing problem on smp

[Pablo Sebastian Greco <lkml@fliagreco.com.ar>]

Arjan van de Ven wrote:
> Pablo Sebastian Greco wrote:
>
> > 2296:        427        426        436  134563009   PCI-MSI-edge      
> > eth1
> > 2297:        252        252  135926471        257   PCI-MSI-edge      
> > eth0
>
> this suggests that  cores would be busy rather than only one....
> -
Yes, but you are looking at mm kernel statistics, but if you look at the 
standard kernel, you'll see that eth interrupts are on the same core 
according to attached /proc/cpuinfo.
OTOH, take a look at timer interrupt distribution

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 6
model name      :                   Intel(R) Xeon(TM) CPU 2.66GHz
stepping        : 4
cpu MHz         : 2656.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 6
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est cid cx16 xtpr lahf_lm
bogomips        : 5324.82
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 6
model name      :                   Intel(R) Xeon(TM) CPU 2.66GHz
stepping        : 4
cpu MHz         : 2656.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 1
cpu cores       : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 6
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est cid cx16 xtpr lahf_lm
bogomips        : 5320.06
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor       : 2
vendor_id       : GenuineIntel
cpu family      : 15
model           : 6
model name      :                   Intel(R) Xeon(TM) CPU 2.66GHz
stepping        : 4
cpu MHz         : 2656.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 0
cpu cores       : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 6
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est cid cx16 xtpr lahf_lm
bogomips        : 5320.20
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor       : 3
vendor_id       : GenuineIntel
cpu family      : 15
model           : 6
model name      :                   Intel(R) Xeon(TM) CPU 2.66GHz
stepping        : 4
cpu MHz         : 2656.000
cache size      : 2048 KB
physical id     : 0
siblings        : 4
core id         : 1
cpu cores       : 2
fpu             : yes
fpu_exception   : yes
cpuid level     : 6
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm syscall nx lm constant_tsc pni monitor ds_cpl vmx est cid cx16 xtpr lahf_lm
bogomips        : 5320.16
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management: