3 ms·
No, because you aren't writing directly to the frame buffer, you have to go through drivers, kernels and PCIe bus.
by BubRoss 7y ago
No, because you aren't writing directly to the frame buffer, you have to go through drivers, kernels and PCIe bus.
- MuffinFlavored 7y agoWhat do the drivers in the kernel talking to the device do over the PCI-e bus? Just send data, right?
- BubRoss 7y agoIn the previous scenario the cpu isn't running using virtual memory and doesn't need to go through the kernel to do something outside of writing to its isolated memory space. It can write to certain memory addresses that make up the frame buffer that the screen is being drawn from. This is not how a modern PC works. There are system calls (specific assembly instructions) that a user space program can use to communicate with global resources. These go through the kernel and thus are an escape hatch to isolated processes. These are two very different scenarios with the fundamental difference between virtual memory and multiple isolated processes. There isn't much semantic wiggle room.