[Oisf-users] Question about IRQs affinity on all machine cores

[Fernando Sclavo]

Hi! Trying to find out why our IDS is dropping packets, we can see that
IRQs are not evenly distributed on all cores (we run Intel
/ixgbe-3.14.5/scripts/set_irq_affinity eth5 eth7 to do it). Instead, all
IRQs are mapped to socket 1.

If you see the top output below, is clear that all interrupts from both
NICs are serviced by CPU1, how can we distribute IRQs on all 32 cores?

Cores 0-15 are CPU 1, and cores 16/31 are CPU 2.

top - 17:15:10 up  1:42,  1 user,  load average: 12.69, 14.29, 14.43
Tasks: 271 total,  31 running, 240 sleeping,   0 stopped,   0 zombie
Cpu0  : 63.5%us,  3.0%sy,  0.0%ni, 29.6%id,  0.0%wa,  0.0%hi,  3.9%si,
0.0%st
Cpu1  : 64.0%us,  1.6%sy,  0.0%ni, 27.0%id,  0.0%wa,  0.0%hi,  7.4%si,
0.0%st
Cpu2  : 60.4%us,  1.6%sy,  0.0%ni, 33.3%id,  0.0%wa,  0.0%hi,  4.7%si,
0.0%st
Cpu3  : 48.2%us,  2.0%sy,  0.0%ni, 46.7%id,  0.0%wa,  0.0%hi,  3.0%si,
0.0%st
Cpu4  : 55.4%us,  1.5%sy,  0.0%ni, 38.5%id,  0.0%wa,  0.0%hi,  4.6%si,
0.0%st
Cpu5  : 53.7%us,  2.1%sy,  0.0%ni, 41.0%id,  0.0%wa,  0.0%hi,  3.2%si,
0.0%st
Cpu6  : 60.2%us,  2.0%sy,  0.0%ni, 31.3%id,  0.0%wa,  0.0%hi,  6.5%si,
0.0%st
Cpu7  : 49.8%us,  2.5%sy,  0.0%ni, 44.8%id,  0.0%wa,  0.0%hi,  3.0%si,
0.0%st
Cpu8  : 52.6%us,  2.1%sy,  0.0%ni, 41.2%id,  0.0%wa,  0.0%hi,  4.1%si,
0.0%st
Cpu9  : 49.5%us,  1.1%sy,  0.0%ni, 45.8%id,  0.0%wa,  0.0%hi,  3.7%si,
0.0%st
Cpu10 : 53.7%us,  2.1%sy,  0.0%ni, 39.5%id,  0.0%wa,  0.0%hi,  4.7%si,
0.0%st
Cpu11 : 52.4%us,  1.0%sy,  0.0%ni, 44.0%id,  0.0%wa,  0.0%hi,  2.6%si,
0.0%st
Cpu12 : 57.5%us,  2.5%sy,  0.0%ni, 35.5%id,  0.0%wa,  0.0%hi,  4.5%si,
0.0%st
Cpu13 : 41.5%us,  3.1%sy,  0.0%ni, 52.8%id,  0.0%wa,  0.0%hi,  2.6%si,
0.0%st
Cpu14 : 56.3%us,  3.0%sy,  0.0%ni, 35.0%id,  0.0%wa,  0.0%hi,  5.6%si,
0.0%st
Cpu15 : 54.5%us,  3.0%sy,  0.0%ni, 37.6%id,  0.0%wa,  0.0%hi,  5.0%si,
0.0%st
Cpu16 : 16.9%us,  0.0%sy,  0.0%ni, 83.1%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu17 :  7.0%us,  0.0%sy,  0.0%ni, 93.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu18 :  7.0%us,  0.0%sy,  0.0%ni, 93.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu19 :  3.0%us,  0.0%sy,  0.0%ni, 97.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu20 :  5.5%us,  0.0%sy,  0.0%ni, 94.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu21 :  0.5%us,  0.0%sy,  0.0%ni, 99.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu22 :  1.5%us,  0.0%sy,  0.0%ni, 98.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu23 :  2.0%us,  0.0%sy,  0.0%ni, 98.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu24 : 16.6%us,  0.0%sy,  0.0%ni, 83.4%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu25 :  9.5%us,  0.5%sy,  0.0%ni, 89.9%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu26 : 11.0%us,  0.0%sy,  0.0%ni, 89.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu27 :  4.5%us,  0.0%sy,  0.0%ni, 95.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu28 : 14.5%us,  0.0%sy,  0.0%ni, 85.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu29 :  3.0%us,  0.0%sy,  0.0%ni, 97.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu30 : 13.0%us,  0.0%sy,  0.0%ni, 87.0%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Cpu31 :  8.5%us,  0.0%sy,  0.0%ni, 91.5%id,  0.0%wa,  0.0%hi,  0.0%si,
0.0%st
Mem:  198002932k total, 35837232k used, 162165700k free,    29800k buffers
Swap: 15624188k total,        0k used, 15624188k free,  4419012k cached


Thanks in advance.
Regards
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