4 ms·

(2017) Previous discussion: https://news.ycombinator.com/item?id=14798211 https://news.ycombinator.com/item?id=14798211

by nxrabl 8y ago

sevensor 8y ago
I'd love to see a followup study. GPU based terminal emulators (alacritty, kitty) have evolved a lot over the last two years.
- llimllib 8y ago
  iTerm is a GPU based terminal emulator now too, as long as the metal backend is active
- swiley 8y ago
  My personal experience with GPU accelerated GUIs is that latency is always worse. Drawing text is something that the cpu is pretty good at and the GPU just means more back and forth over the buss, more driver coupling, more weird libraries.
  - sevensor 8y ago
    That would be my concern. But there are so many factors, I'd like to see some scientific measurement.
  - 1996 8y ago
    Matches user reports like https://stackoverflow.com/questions/42888024/git-bash-mintty-is-extremely-slow-on-windows-10-os https://stackoverflow.com/questions/42888024/git-bash-mintty...
  - raphlinus 8y ago
    I think you're right about GPU tending to have worse latency, but I think it's because that's the way the swap chain is set up and the use of blocking present calls. I've been studying this and am pretty sure I know how to make low latency on Windows work, mostly it's following the advice in [1]. If you do it right, then on modern hardware, DirectFlip kicks in and that saves you an additional frame that would ordinarily be eaten by the compositor. I plan to measure this at some point in the not too distant future, or would be happy to mentor somebody interested in taking it on. [1]: https://devblogs.microsoft.com/directx/dxgi-flip-model/ https://devblogs.microsoft.com/directx/dxgi-flip-model/
- mpweiher 8y ago
  AFAIK, GPUs are throughput devices, not latency-reducing devices. Happy to be proven wrong!
- deleted 8y ago
  [deleted]
c_r_w 8y ago
Thanks, I knew I had seen this before but unbelievably there is no date on that article.
- dang 8y ago
  Submissions on HN only get dated when they are aren't from the current year. That one was.

(2017) Previous discussion: https://news.ycombinator.com/item?id=14798211 https://news.ycombinator.com/item?id=14798211

by nxrabl 8y ago

(2017) Previous discussion: https://news.ycombinator.com/item?id=14798211 https://news.ycombinator.com/item?id=14798211

I'd love to see a followup study. GPU based terminal emulators (alacritty, kitty) have evolved a lot over the last two years.

llimllib 8y ago
iTerm is a GPU based terminal emulator now too, as long as the metal backend is active
swiley 8y ago
My personal experience with GPU accelerated GUIs is that latency is always worse. Drawing text is something that the cpu is pretty good at and the GPU just means more back and forth over the buss, more driver coupling, more weird libraries.
- sevensor 8y ago
  That would be my concern. But there are so many factors, I'd like to see some scientific measurement.
- 1996 8y ago
  Matches user reports like https://stackoverflow.com/questions/42888024/git-bash-mintty-is-extremely-slow-on-windows-10-os https://stackoverflow.com/questions/42888024/git-bash-mintty...
- raphlinus 8y ago
  I think you're right about GPU tending to have worse latency, but I think it's because that's the way the swap chain is set up and the use of blocking present calls. I've been studying this and am pretty sure I know how to make low latency on Windows work, mostly it's following the advice in [1]. If you do it right, then on modern hardware, DirectFlip kicks in and that saves you an additional frame that would ordinarily be eaten by the compositor. I plan to measure this at some point in the not too distant future, or would be happy to mentor somebody interested in taking it on. [1]: https://devblogs.microsoft.com/directx/dxgi-flip-model/ https://devblogs.microsoft.com/directx/dxgi-flip-model/
mpweiher 8y ago
AFAIK, GPUs are throughput devices, not latency-reducing devices. Happy to be proven wrong!
deleted 8y ago
[deleted]

c_r_w 8y ago

Thanks, I knew I had seen this before but unbelievably there is no date on that article.

dang 8y ago
Submissions on HN only get dated when they are aren't from the current year. That one was.