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I guess I'm just looking for some evidence to support the decision to use GPU. Show some framerate benchmarks, some CPU usage comparisons, etc.

dahart 5y ago
Why does it need “evidence”? GPUs are fast and good at displaying pixels. Moving rendering to the GPU lets the CPU focus on things it’s good at rather than bog it down with a high bandwidth task that has to go to the GPU anyway. Lots of editors have been getting GPU acceleration (I use Sublime and Visual Studio among others, both have hardware acceleration). All major browsers and operating systems support hardware accelerated drawing. Video games of course… I think the question is why wouldn’t you use the GPU for rendering these days? It’s a pixel processor that nearly everyone has in their machine. What evidence is there to support the decision to render pixels on a CPU rather than use the rendering co-processor?
- anthk 5y ago
  Because that's snake oil. I had accelerated 2D since XV days (XVideo extension for X) back in 2003.
  - dahart 5y ago
    I’m very confused by that comment, what do you mean snake oil? Are you saying GPUs don’t do anything? Isn’t the XV you’re referring to in the same category as today’s GPU wrt parent’s comment? @cosmotic asked for evidence why not to use the CPU, and XV is not implemented on the CPU. Also it looks like XV did video resizing and some color mapping (https://en.wikipedia.org/wiki/X_video_extension https://en.wikipedia.org/wiki/X_video_extension). Today’s GPUs are doing the rendering. Filling the display buffer using primitives and textures, and outputting the display buffer are different activities that are both done by the GPU today, but it sound like XV didn’t do the first part at all, and that first part is what we’re talking about here.
    - anthk 5y ago
      Ok, maybe not XV, but X11/Xorg was 2D accelerated back in the days, for sure. X without 2D acceleration was crawlish even under my AMD Athlon.
  - cosmotic 5y ago
    If GPUs are good at displaying pixels, the benchmarks and evidence should be easy to come by. As I mentioned in another comment, I use iTerm2 and it's GPU acceleration has no visual impact but makes CPU usage much higher while sitting idle. Turning it off is a huge improvement.
    - dahart 5y ago
      Evidence is super easy to come by, but the question does need to be specific and well formed (what kind of rendering, exactly, are we comparing, how many pixels, what’s the bottleneck, etc.). There are loads and loads of benchmarks demonstrating GPUs are faster than CPUs at turning triangles into pixels. Not just a little faster, the numbers are usually in the ~100x range. There’s literally zero contention on this point, nobody is questioning whether simple rendering cases might be faster. Nobody is playing Fortnite with CPU rendering. Because this question is so well settled, GPU rendering is so ubiquitous that it’s even hard to test CPU software rendering. There are certain kinds of rendering and corner cases where CPUs can have an edge, but those happen in areas like scientific visualization or high end VFX, they don’t come up often in text editor rendering engines. You can’t use your anecdote of 1 app that might have a broken implementation to question GPUs categorically. I’ve never noticed iTerm2 using significant CPU. My iTerm2 sits at 0.0% CPU while idle. Maybe your install is busted?

dahart 5y ago

Why does it need “evidence”? GPUs are fast and good at displaying pixels. Moving rendering to the GPU lets the CPU focus on things it’s good at rather than bog it down with a high bandwidth task that has to go to the GPU anyway. Lots of editors have been getting GPU acceleration (I use Sublime and Visual Studio among others, both have hardware acceleration). All major browsers and operating systems support hardware accelerated drawing. Video games of course… I think the question is why wouldn’t you use the GPU for rendering these days? It’s a pixel processor that nearly everyone has in their machine. What evidence is there to support the decision to render pixels on a CPU rather than use the rendering co-processor?

anthk 5y ago
Because that's snake oil. I had accelerated 2D since XV days (XVideo extension for X) back in 2003.
- dahart 5y ago
  I’m very confused by that comment, what do you mean snake oil? Are you saying GPUs don’t do anything? Isn’t the XV you’re referring to in the same category as today’s GPU wrt parent’s comment? @cosmotic asked for evidence why not to use the CPU, and XV is not implemented on the CPU. Also it looks like XV did video resizing and some color mapping (https://en.wikipedia.org/wiki/X_video_extension https://en.wikipedia.org/wiki/X_video_extension). Today’s GPUs are doing the rendering. Filling the display buffer using primitives and textures, and outputting the display buffer are different activities that are both done by the GPU today, but it sound like XV didn’t do the first part at all, and that first part is what we’re talking about here.
  - anthk 5y ago
    Ok, maybe not XV, but X11/Xorg was 2D accelerated back in the days, for sure. X without 2D acceleration was crawlish even under my AMD Athlon.
- cosmotic 5y ago
  If GPUs are good at displaying pixels, the benchmarks and evidence should be easy to come by. As I mentioned in another comment, I use iTerm2 and it's GPU acceleration has no visual impact but makes CPU usage much higher while sitting idle. Turning it off is a huge improvement.
  - dahart 5y ago
    Evidence is super easy to come by, but the question does need to be specific and well formed (what kind of rendering, exactly, are we comparing, how many pixels, what’s the bottleneck, etc.). There are loads and loads of benchmarks demonstrating GPUs are faster than CPUs at turning triangles into pixels. Not just a little faster, the numbers are usually in the ~100x range. There’s literally zero contention on this point, nobody is questioning whether simple rendering cases might be faster. Nobody is playing Fortnite with CPU rendering. Because this question is so well settled, GPU rendering is so ubiquitous that it’s even hard to test CPU software rendering. There are certain kinds of rendering and corner cases where CPUs can have an edge, but those happen in areas like scientific visualization or high end VFX, they don’t come up often in text editor rendering engines. You can’t use your anecdote of 1 app that might have a broken implementation to question GPUs categorically. I’ve never noticed iTerm2 using significant CPU. My iTerm2 sits at 0.0% CPU while idle. Maybe your install is busted?