irqbalance superfluous
Istimsak Abdulbasir
saqman2060 at gmail.com
Thu Apr 9 12:31:24 UTC 2015
On Apr 9, 2015 8:20 AM, "John Moser" <john.r.moser at gmail.com> wrote:
>
> 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.
>
I see. Splitting interrupt handling evenly between CPUs. That is of course,
there are multiple CPUs. How do I know my kernel is using irqbalance?
> 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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