What do you know about regarding IRQ processing methods + drivers? (line-based vs message-based)

In a thread here: http://forums.guru3d.com/showthread.php?t=378044

…it discusses IRQ’s, particularly the difference between line-based IRQ’s vs. message-based ones. It discusses a tweak for possibly switching devices from using the older line-based IRQ’s (hard-wired based) to the newer and more efficient message-based (using memory locations/access instead of hard-wired).

Supposedly, this can improve a system’s performance, particularly if there are a number of devices that are sharing IRQ’s.

In that thread, a number of people mentioned that install updated Intel drivers + Intel RST automatically switched a number of their controllers/devices to the newer message-based method, without them having to manually tweak this via registry.

Do you know anything about this? Is there potential benefit to be gained from doing this?

Looking at my own current x58 system, I can see that I only have one device which is (apparently) using message-based: my AMD GPU. All of the other controllers, such as I/O, PCIe, USB, network, SATA, audio, etc. – they’re all on line-based IRQ’s, and most of them are stacked with others on one IRQ. For example, IRQ 16 has eight devices stacked on it!

Anyway, I’m wondering what your thoughts are regarding this, and if it’d be helpful if I tweaked these to all try to use message-based, or perhaps if installing RST might possibly help in this. I’m currently on Intel 11.x.1006 (AHCI).


Here’s a paragraph in that thread giving some more insight into this (I thought it’d be helpful for anyone new to this, as I am):

Fernando, are you there? Just wondering if you have an opinion regarding this. Thanks.

Yes, I am here, but not there.

Unfortunately I am not an expert regarding this topic.

There is no definitive answer, it should be tested individually. I have seen drivers that ignore this setting, others that give a yellow bang, others that BSOD. I believe mbk1969 has written a tool for easily changing to MSI interrupts, among other useful utilities.

Very Socratic of you :slight_smile:

K thanks. I’ll look up mbk1969 and try out his utility(ies) to see how it fares. I appreciate the info.