Glossary
AIC (Apple Interrupt Controller)
The SoC's interrupt aggregator on Apple Silicon. Routes interrupts from devices to specific CPU clusters with per-source priority and masking.
The AIC — Apple Interrupt Controller — is the SoC-level interrupt aggregator on Apple Silicon. Every interrupt source on the chip (the GPU, every PCIe device, every USB controller, every sensor) wires through it.
Its responsibilities:
- Per-source mask/enable — the kernel can individually disable any source.
- Per-source target routing — each interrupt can be directed at a specific CPU cluster (P or E).
- Priority dispatch — high-priority interrupts preempt low-priority ones.
When a device asserts an interrupt line, the AIC selects a target CPU, records the source ID, and raises an interrupt on the chosen core. The kernel's sleh.c IRQ handler reads the AIC's "what fired" register to identify the source.
The AIC is the Apple-Silicon equivalent of an x86 APIC or an ARM GIC, but with Apple-specific extensions for cluster-aware routing.
See also: the interrupt handling article, the Apple Silicon article.