Message Signaled Interrupts (MSI)

In modern PCs you find PCIe cards that can use MSI. MSI directly generates interrupt vectors.

If your device supports MSI then you can tell the RT kernel to use this feature to invoke your interrupt handler. Some devices can generate multiple interrupt vectors to signal different conditions or else to signal different cores. Multiple MSI support is available in INtime.

MSI handlers are never shared, since each MSI event generates a different interrupt vector. This has two advantages; the performance is slightly better than a shared handler because only one is called, and the device is isolated from any other interrupt source.