Inter-processor interrupt

An inter-processor interrupt (IPI) is a special type of interrupt by which one processor may interrupt another processor in a multiprocessor system. IPIs are typically used to implement a cache coherency synchronization point.

In a Windows based multiprocessor system, a processor may interrupt another processor for the following reasons:

1. Queue a DISPATCH_LEVEL interrupt to schedule a particular thread for execution.
2. Updating the processor's translation look-aside buffers cache.
3. System shutdown.
4. System crash.
5. Kernel debugger breakpoint.

In Windows, this has IRQL as 29.

In x86 based systems, an IPI synchronizes the cache and Memory Management Unit (MMU) between processors.

See also

• Advanced Programmable Interrupt Controller
• Interrupt
• Interrupt handler
• Non-maskable interrupt
• Programmable Interrupt Controller