3 ms·

With regard to latency sensitivity, with so many cores available, a single core could be dedicated to processing mouse input. Of course, if there's a lock in t

by chrsig 4y ago

With regard to latency sensitivity, with so many cores available, a single core could be dedicated to processing mouse input. Of course, if there's a lock in the way that's held, that's still a problem.

astrange 4y ago
Or if it needs code that’s paged out or all cores are thermal limited or the GPU hung. CPU time usually isn’t the limiting factor.
PaulHoule 4y ago
For a modern system like Wayland or WDM, the display compositor gets rectangles of pixels from the applications, copies those into a big rectangle it sends to the rasterizer. Just before it does that, it draws on a mouse cursor. It also has to communicate with the applications about what image to draw so you have to deal with multiple threads no matter what. (Unless you go back to the late 8-bit era where the cursor might be a just a hardware sprite that can be moved around by writing a few bytes.)
- Rusky 4y ago
  I believe the mouse cursor is still often a hardware sprite today.
  - db48x 4y ago
    Almost 100% guaranteed, but it is still possible for the OS to be delayed in sending it the coordinates. Of course that means that the OS is badly written.
    - yamtaddle 4y ago
      By these standards, the only well-written operating systems I've ever seen are BeOS and QNX/Photon. Probably iOS (at least, older versions of it) deserves to be on the list, despite mouse use being atypical. Which... yeah, that actually might be true.
      - db48x 4y ago
        iOS is the odd one out, because user input has first priority. IIRC, it cannot even do network I/O if you are holding your finger on the screen; all interrupts except those from the touchscreen are disabled for the duration.
    - mijoharas 4y ago
      I can say for sure this is true on sway (wayland) because while messing around seeing if the proprietary nvidia driver finally works yet (when will I learn... for anyone curious nvidia is still nvidia) one of the things I had to do was manually disable hardware cursors.
- pas 4y ago
  sure, no problem, negotiate with the application, but also act as a responsible shepherd of the desktop, if some timeout is exceeded draw the "application is busy" cursor. this already happens, just after some laughably long chain of unprocessed input events

by chrsig 4y ago

astrange 4y ago

Or if it needs code that’s paged out or all cores are thermal limited or the GPU hung. CPU time usually isn’t the limiting factor.

PaulHoule 4y ago

For a modern system like Wayland or WDM, the display compositor gets rectangles of pixels from the applications, copies those into a big rectangle it sends to the rasterizer. Just before it does that, it draws on a mouse cursor. It also has to communicate with the applications about what image to draw so you have to deal with multiple threads no matter what. (Unless you go back to the late 8-bit era where the cursor might be a just a hardware sprite that can be moved around by writing a few bytes.)

Rusky 4y ago
I believe the mouse cursor is still often a hardware sprite today.
- db48x 4y ago
  Almost 100% guaranteed, but it is still possible for the OS to be delayed in sending it the coordinates. Of course that means that the OS is badly written.
  - yamtaddle 4y ago
    By these standards, the only well-written operating systems I've ever seen are BeOS and QNX/Photon. Probably iOS (at least, older versions of it) deserves to be on the list, despite mouse use being atypical. Which... yeah, that actually might be true.
    - db48x 4y ago
      iOS is the odd one out, because user input has first priority. IIRC, it cannot even do network I/O if you are holding your finger on the screen; all interrupts except those from the touchscreen are disabled for the duration.
  - mijoharas 4y ago
    I can say for sure this is true on sway (wayland) because while messing around seeing if the proprietary nvidia driver finally works yet (when will I learn... for anyone curious nvidia is still nvidia) one of the things I had to do was manually disable hardware cursors.
pas 4y ago
sure, no problem, negotiate with the application, but also act as a responsible shepherd of the desktop, if some timeout is exceeded draw the "application is busy" cursor. this already happens, just after some laughably long chain of unprocessed input events