Why an interrupt is not being delivered across multiple CPUs when the interrupt has been routed to multiple CPUs by setting /proc/irq/IRQ_NUMBER/smp_affinity in RHEL?
Issue
Interrupts are routed to multiple CPUs as indicated in /proc/IRQ_NUMBER/smp_affinity mask but are delivered only to a first CPU in that mask.
For example, smp_affinity file might contain mask 0xFF for particular interrupt but irqs are delivered only to CPU 0.
Environment
- Red Hat Enterprise Linux 6, 7 or 8
- x86 architecture (both 32-bit and 64-bit kernel modes)
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