DMA-Fence Deadline Awareness Proposed To Help Ensure GPU Drivers Render On-Time

[phoronix]

Phoronix: DMA-Fence Deadline Awareness Proposed To Help Ensure GPU Drivers Render On-Time

There is the phenomenon on Linux where when double-buffered rendering and missing vblanks can lead to the GPU running at a lower frequency when instead the opposite should happen so it will try to not miss vblanks in the first place. In the past there's been talks of "boost" support in the GPU drivers or also workarounds from user-space like dynamic triple buffering, but sent out this week is a new proposal around DMA-Fence deadline awareness as another means of addressing this problem...

https://www.phoronix.com/scan.php?page=news_item&px=DMA-Fence-Deadline-Awareness

[Hibbelharry]

Doesn't this try to fix the same issues that van vugt is trying to solve via triple buffering in gnome-shell?

[bregma]

I would like to know what Daniel van Vugt's opinion on this.

[GreatLord]

Yes it is and issue and most correct fix is what Rob doing, trippel buffer can solv same issue and it have it Good and bad Side. It can use both method same times . I want see Rob solutions it is is best way to solv it property once for all

[tildearrow]

Making a good compositor:

1. Super-lightweight. The compositor has to be the lightest part on the desktop.
2. Important. The compositor shall run with high priority, immediately taking over rendering near the end of a frame.
3. Real-time. The compositor must predict how long will a frame take to render and estimate when to start drawing the next frame.

[timofonic]

Making a good compositor:

1. Super-lightweight. The compositor has to be the lightest part on the desktop.
2. Important. The compositor shall run with high priority, immediately taking over rendering near the end of a frame.
3. Real-time. The compositor must predict how long will a frame take to render and estimate when to start drawing the next frame.

Are there feature complete compositors following strictly those rules and being quite robust too? Are they part of a DE?

[royce]

Sway certainly is the lightest part of the desktop. It does run at default (0) priority and I've no idea if it's realtime. It however has impeccable latency and performance, even with many displays connected at different dpi and frequencies.