Understanding the Vertical Sync Interrupt

Understanding the Vertical Sync Interrupt

In systems with dedicated graphics hardware, the graphics hardware generates a variety of hardware interrupts. The most frequent of these is the vertical sync interrupt, which marks the end of a video frame. The vertical sync interrupt can be used by the Frame Scheduler as a time base (see "Vertical Sync Interrupt"). Certain GL and Open GL functions are internally synchronized to the vertical sync interrupt (for an example, refer to the gsync(3g) reference page).

All the interrupts produced by dedicated graphics hardware are at an inferior priority compared to other hardware. All graphics interrupts including the vertical sync interrupt are directed to CPU 0. They are not "sprayed" in rotation, and they cannot be directed to a different CPU.