irqbalance superfluous
John Moser
john.r.moser at gmail.com
Thu Apr 9 12:19:21 UTC 2015
IRQbalance keeps all of the IRQ requests from backing up on a single
CPU. It tries to balance this out in an intelligent way accross all the
CPUs and, when possible, puts the IRQ processing as close to the process
as possible.
On NUMA systems, you may want numad. I believe irqbalance exits if it
detects NUMA.
On 04/09/2015 08:14 AM, Istimsak Abdulbasir wrote:
> What is the irqbalance and what was the reason for using it?
>
> On Apr 9, 2015 8:09 AM, "Daniel J Blueman" <daniel at quora.org
> <mailto:daniel at quora.org>> wrote:
>
> Checked with Vivid beta on Intel i5 hardware, and it seems interrupt
> distribution doesn't change when I boot with irqbalance running [1],
> or after purging it and rebooting [2].
>
> Finally, it can't second guess MSI interrupt setup better than the
> APIC driver and adds a unnecessary layer of 'intelligence'. I don't
> see any case common enough to warrant deploying it by default.
>
> Anyone against removing it?
>
> Dan
>
> -- [1]
>
> root at nuc:~# cat /proc/interrupts
> CPU0 CPU1 CPU2 CPU3
> 0: 18 0 0 0 IR-IO-APIC-edge
> timer
> 1: 1 1 0 1 IR-IO-APIC-edge
> i8042
> 7: 9 0 0 0 IR-IO-APIC-edge
> 8: 0 0 0 1 IR-IO-APIC-edge
> rtc0
> 9: 3 0 0 0
> IR-IO-APIC-fasteoi acpi
> 12: 1 2 1 0 IR-IO-APIC-edge
> i8042
> 23: 11 1 15 6 IR-IO-APIC
> 23-fasteoi ehci_hcd:usb3
> 40: 0 0 0 0 DMAR_MSI-edge
> dmar0
> 41: 0 0 0 0 DMAR_MSI-edge
> dmar1
> 42: 0 0 0 0 IR-PCI-MSI-edge
> PCIe PME
> 43: 0 0 0 0 IR-PCI-MSI-edge
> PCIe PME
> 44: 87 25 95 23 IR-PCI-MSI-edge
> xhci_hcd
> 45: 2740 4911 4405 14870 IR-PCI-MSI-edge
> 0000:00:1f.2
> 46: 10 10 2504 3 IR-PCI-MSI-edge
> eth0
> 47: 12 1 1 0 IR-PCI-MSI-edge
> mei_me
> 48: 8 14 3 1 IR-PCI-MSI-edge
> iwlwifi
> 49: 496 594 290 331 IR-PCI-MSI-edge
> i915
> 50: 197 80 4 39 IR-PCI-MSI-edge
> snd_hda_intel
> 51: 721 0 0 28 IR-PCI-MSI-edge
> snd_hda_intel
> NMI: 1 1 0 1 Non-maskable
> interrupts
> LOC: 30046 19983 13391 18318 Local timer
> interrupts
> SPU: 0 0 0 0 Spurious interrupts
> PMI: 1 1 0 1 Performance
> monitoring interrupts
> IWI: 0 0 0 0 IRQ work interrupts
> RTR: 2 0 0 0 APIC ICR read retries
> RES: 943 1130 618 693 Rescheduling
> interrupts
> CAL: 840 699 674 747 Function call
> interrupts
> TLB: 198 205 286 1241 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: 4 4 4 4 Machine check polls
> HYP: 0 0 0 0 Hypervisor callback
> interrupts
> ERR: 9
> MIS: 0
>
> -- [2]
>
> root at nuc:~# cat /proc/interrupts
> CPU0 CPU1 CPU2 CPU3
> 0: 20 0 0 0 IR-IO-APIC-edge
> timer
> 1: 1 0 1 1 IR-IO-APIC-edge
> i8042
> 7: 11 0 0 0 IR-IO-APIC-edge
> 8: 0 0 0 1 IR-IO-APIC-edge
> rtc0
> 9: 3 0 0 0
> IR-IO-APIC-fasteoi acpi
> 12: 3 0 1 0 IR-IO-APIC-edge
> i8042
> 23: 15 10 10 0 IR-IO-APIC
> 23-fasteoi ehci_hcd:usb3
> 40: 0 0 0 0 DMAR_MSI-edge
> dmar0
> 41: 0 0 0 0 DMAR_MSI-edge
> dmar1
> 42: 0 0 0 0 IR-PCI-MSI-edge
> PCIe PME
> 43: 0 0 0 0 IR-PCI-MSI-edge
> PCIe PME
> 44: 48 9 98 11 IR-PCI-MSI-edge
> xhci_hcd
> 45: 3592 754 4633 1272 IR-PCI-MSI-edge
> 0000:00:1f.2
> 46: 37 23 89 13 IR-PCI-MSI-edge
> eth0
> 47: 14 0 0 0 IR-PCI-MSI-edge
> mei_me
> 48: 291 0 4 25 IR-PCI-MSI-edge
> snd_hda_intel
> 49: 12 16 6 0 IR-PCI-MSI-edge
> iwlwifi
> 50: 246 132 154 288 IR-PCI-MSI-edge
> i915
> 51: 25 673 13 42 IR-PCI-MSI-edge
> snd_hda_intel
> NMI: 0 0 0 0 Non-maskable
> interrupts
> LOC: 1041 1680 928 964 Local timer
> interrupts
> SPU: 0 0 0 0 Spurious interrupts
> PMI: 0 0 0 0 Performance
> monitoring interrupts
> IWI: 0 0 1 0 IRQ work interrupts
> RTR: 3 0 0 0 APIC ICR read retries
> RES: 374 517 311 305 Rescheduling
> interrupts
> CAL: 638 640 679 609 Function call
> interrupts
> TLB: 1628 93 49 110 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
> HYP: 0 0 0 0 Hypervisor callback
> interrupts
> ERR: 11
> MIS: 0
> --
> Daniel J Blueman
>
> --
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