5 ms·

I built a GPU back end for Emacs

193 points by andros 4mo ago

semessier 4mo ago
cudos
- andros 4mo ago
  Why?
  - _f9cu 4mo ago
    What's the article talking about?
- qrios 4mo ago
  A new CUDA API? For DOS?
  - saltcured 4mo ago
    No, CUDOS is using CUDA as your OS. What that has to do with this article about a new device driver for the EMACS OS, I don't quite know...
skydhash 4mo ago
This was almost a good read (a very good goal and a sensible approach), But the pacing of the article smells of LLM. I would suggest to do another pass at editing it out as it diminishes the story.
- andros 4mo ago
  If you've reached that conclusion, I'm truly proud of my writing technique. I'm sorry to say, though, that your instincts are failing you this time. I write my articles by hand over several days, although it's true that I do consult AI to improve my style, expressions, find synonyms, create tables, and correct spelling mistakes. Thank you for your comment!
  - reinitctxoffset 4mo ago
    FWIW no one can tell anymore. Claude stopped doing all the LLM ticks like 6 months ago. There's a whole industry of people trying to detect LLM writing and they're getting stomped, this can be and is extremely well studied in the literature. The criticism is that you did something wildly ambitious and pulled it off. The blog is just well written.
    - tom_ 4mo ago
      People clearly can, though, because they did.
      - reinitctxoffset 4mo ago
        I'm inclined to believe the author, given that they were honest about the machine assist on the engineering? Why would they lie about the post and not the artifact? More broadly, I'm just getting tired of the low effort snark on this. If someone is going to cite a passage, or examples of a theme, do some serious analysis by all means. I'm not trying to tone police high effort comments. But this drive by "that's LLM output" thing is the new low effort "javascript is just as hard as c++" a.k.a "i don't know how to do that and i have no intention of learning and it feels bad so i'm going to lash out". Make a case that something is deficient on its merits or don't, but baseless accusations of dishonesty are not a reasonable default. The parent here did real work that no one paid them to do, donated it to the community asking nothing in return, it's meticulous and high value, and they've already been run over by the FSF goons, you really want to pile on with no evidence?
        tom_ 4mo ago
        I'm inclined to believe them too, so when he said he used LLMs to tweak the wording, I'll accept that was the case. Perhaps the opening post was ill-phrased, but I think the second post clarifies it a bit: https://news.ycombinator.com/item?id=48677597 https://news.ycombinator.com/item?id=48677597 - and I was certainly getting some vague LLM vibes from the writing, so I was curious about this too. So, whatever it is in the LLM output that is detectable, it's clearly detectable, even with the latest LLMs, and even when it's present possibly only in trace quantities.
- ghosty141 4mo ago
  Very much this. I really dislike the somewhat corporate and characterless sounding tone of AI. I really liked the part where he tried to get it into upstream emacs, most of these type of projects never even get there. But yeah things like "bring honest numbers" sounds just weird.
  - andros 4mo ago
    Please, have some mercy, English is not my first language! Thanks for the advice, I'll keep it in mind.
    - nh23423fefe 4mo ago
      dont listen to insane people obsessed with llm hatred. thanks for the article
    - ghosty141 4mo ago
      hey, honestly I personally wouldnt mind "unusual" english or some weird sentences. Obviously using AI to proofread and give suggestions is great use of it and I dont see a problem in that. Not a native speaker either so I can definitely relate :) I hope I didnt come off as too harsh, its just due to me seeing a lot of half-baked blog spam on r/emacs Ive gotten a bit sensitive when noticing AI writing.
    - green7ea 4mo ago
      People are paranoid that everything they read was written by a LLM. It's likely that they are even more suspicious because you used one to code. You should be proud of both the work you did and the article :-).
    - iLemming 4mo ago
      I honestly just don't get it. I feel people just whine for the sake of complaining about it, to get a feeling of some kind of moral superiority, or something. It's as if they're reading some GRR Martin kind of novel and the dragon slaying portrayal isn't up to their liking. It's not a fucking prose, learn how to extract useful information from a text, you're goddamn programmers, you've been mentally deciphering literal code, probably for a long fucking time, just fucking scan the text with your eyes and comprehend the meaning with your brain. If you don't like the style, just ask the LLM to summarize it for you, dang it. It's like if someone said: "your text appears to be typed in Emacs, sorry, but I won't read it. Try using a less controversial editor next time. Good effort though." Oh fuck you! Don't read it, who cares? Why come complaining about it? I feel like smacking them on the forehead, saying: "good job, you got me, I used AI, now what? Call the police, shoot me, cancel me, send complaints, clog my toilet..." Enormously annoying. More annoying that actually reading text written with AI assistance.
juancn 4mo ago
Doesn't just emacs render to a tty? Or is this for some Emacs build with its own renderer?
- andros 4mo ago
  This is for the GUI build of Emacs, not the terminal (tty) version. Emacs has had a native GUI renderer since the 90s, on macOS it uses Cocoa/NS, on Linux it uses GTK or raw X11. This project replaces that CPU-based drawing pipeline with a GPU backend: Metal on macOS and OpenGL/EGL on Linux. The tty build is unaffected.
sph 4mo ago
https://github.com/tanrax/emacs-gpu/blob/main/.github/assets/bench-linux-4k.png https://github.com/tanrax/emacs-gpu/blob/main/.github/assets... This massive speed-up on 4K screens makes me want to try it. The wayland pgtk version has such terrible latency I have to use the X11 build to avoid gnashing teeth during my working hours. And I think it's the X11 version that uses cairo, so the actual speedup in my case might be even larger. I reported the issue years ago, the pgtk maintainer confirmed, say they can't do much as they're using GTK3 which isn't hardware accelerated, so I have to wait until they migrate to GTK4 (in a decade or so). A bit disappointing, but that's open source. Looks like I'm not the only one suffering with a 4K screen: https://old.reddit.com/r/emacs/comments/ucv0at/awful_performance_with_pgtk_on_wayland/ https://old.reddit.com/r/emacs/comments/ucv0at/awful_perform...
- andros 4mo ago
  Good news on the Wayland front: there is already a working branch (wayland-pgtk-backend) that adds a PGTK binding on top of the same EGL/GLES driver, pending merge to main. If you want to try it before that, the branch is available on the repo.
  - zeendo 4mo ago
    I can't find that branch here - https://cgit.git.savannah.gnu.org/cgit/emacs.git https://cgit.git.savannah.gnu.org/cgit/emacs.git Am I looking in the wrong place?
    - stebalien 4mo ago
      https://github.com/tanrax/emacs-gpu/tree/wayland-pgtk-backend https://github.com/tanrax/emacs-gpu/tree/wayland-pgtk-backen... The main emacs-gpu branch doesn't have wayland support.
      - zeendo 4mo ago
        Oh thanks! I thought they meant this was going on in the real emacs man.
drob518 4mo ago
Well done. Here’s hoping that a hand-written GPU backend gets developed based on this wonderful proof of concept. There’s no reason to not take advantage of the state of the art hardware when it’s available. And screens are only moving toward 4k and higher (6k or 8k).
- andros 4mo ago
  Me too. In the meantime, I'll stick with this version :)
- joshjob42 4mo ago
  Or that GNU updates a policy that will very rapidly go from probably net silly/mildly contestedly useful to completely ridiculous in a year or two. Not allowing LLM code will be basically turning down the work of the worlds best programmers running at 50x speed in couple years, and will functionally doom any software project that enforces such a policy.
  - tom_ 4mo ago
    We shall see.
  - vlian2088 4mo ago
    that policy should only ever be relaxed towards legacy contributors and those they can vouch for. otherwise, allowing sloptributions opens the gates to a myriad you-know-who who used to submit pull requests for ESL rewrite of two sequences in README.md and now submit chatgpt-generated refactors - which waste even more human time - just so they can proudly put "open source contributor" on their resumes.
  - agentultra 4mo ago
    Doubt that. If you couldn’t write it yourself you can’t get an LLM to do it for you. So unless you’re attracting the 50 best software developers you’re getting middling to miserable results.
  - deleted 4mo ago
    [deleted]
bingemaker 4mo ago
Great work! Possible to have a patch that I can apply on 32.0.5 and try this out?
- andros 4mo ago
  Yes, of course, I worked with the develop version until at a certain point I decided to downgrade to the stable versions. I'll be releasing more versions later; I'm still focused on fixing minor issues in Linux.
_doctor_love 4mo ago
This is the way! Very nice work. I want it!
- andros 4mo ago
  Thank you!
bjourne 4mo ago
Cool! Regardless of whether your code gets merged, it shows that xdisp.c can be tamed. Like Roger Bannister who ran the miracle mile, you showed that it can be done. Hopefully more will chip in and slay the Emacs redisplay code beast.
- andros 4mo ago
  Thank you, this means a lot!
reinitctxoffset 4mo ago
This is outstanding, if I have time I'll be switching over today. This is the kind of thing that could drive a truly free fork of emacs forward, it's enough better on realistic desktop displays to rally around and as the parent discovered "Free Software" at this point has very little to do with the freedom to do what I want on my computer in a low friction way: an ideological position on "GPUs" as a category is bizarre even by Late Soviet FSF standards. By all means cite a vendor and a policy, but even NVIDIA is in tree now, it's got the same software freedom as ext4 and I don't hear anyone talking about chains on that. In the age of machine assist emacs could get a modern fast/cachable build, clean under all the sanitizers, io_uring on Linux, deterministic clang formatting, compat break with zero-use junk from the 80s, WASM compilation for polyglot extension (I like lisp but I understand why some people don't), modern networking, modern chrome, 100% vscode compatible LSP, modern theming that defaults to something that doesn't drive users away. I would love to have a ten line init.el instead of 4k of workarounds. Maybe this can be the nvim moment. I love emacs but the nvim people have so many nice things and FSF emacs has a shelf life. If someone out of their own time and resources did a cross platform, mechanically verified, dramatically accelerated at HiDPI patch to basically anything else they'd be greeted like a hero. Keep up the good work legend.
- andros 4mo ago
  Thank you! A small correction on framing though: the goal is not a fork but a patch upstream. The backend is structured precisely to minimize the diff against Emacs mainline. The "nvim moment" comparison is flattering but I would rather this be the patch that makes the FSF argument easier to win than the one that splits the community. That said, your list of modernization items is a fair read of the backlog.
- arikrahman 4mo ago
  I agree. Nvim already takes notes out of emacs with major contributors using Funnel to use Lisp as a workaround for working with Lua. This would be a step in the right direction for the continued pioneer emacs proves to be.
- wasting_time 4mo ago
  Just to clarify: the NVIDIA driver is not in-tree, and probably never will be. Intel and AMD are, but require proprietary firmware to work, so the freedom aspect is disputed.
abstractbg 4mo ago
Interesting improvement. My biggest issue with Emacs and the reason that I left it was because it was not multi-threaded. I wonder if is/can be multi-threaded now.
- andros 4mo ago
  You have libraries for multithreading. I use them myself for parallel tasks. However, how events and redrawing work is a completely different matter.
- skydhash 4mo ago
  Concurrency is a source of many bugs and complexity. Emacs have a few async mechanisms and they’re good enough for most tasks. The async nature of other editors does not really matter as you’re still waiting for actions to complete.
- iLemming 4mo ago
  > because it was not multi-threaded I'm honestly curious, what kind of multi-threading you use, in whatever you're using now instead of Emacs? Can you share some practical example(s)? I'm not trying to trick you, I'm just curious for what kind of complex tasks possible there and where Emacs comes short.
  - tmtvl 4mo ago
    Curious that your comment was dead for whatever reason. I vouched for you because I'm also curious at what a user would need concurrency for in a text editor (I mean, granted, Emacs is a Lisp implementation with an amazing text editor attached so in theory someone may want concurrency for programming something in Elisp).
    - andros 4mo ago
      To avoid UI freezes, separate event processing from rendering (for example). It's very common to see the interface freeze while a complex command is running.
  - 4mo ago
arikrahman 4mo ago
Aside from the wonderful contribution to Emacs, I have the utmost respect for how straight-forward you were with the 100% LLM generated code. The enlightening conversation on GPU freedom that ensued was also informative.
- andros 4mo ago
  I completely agree with you. For me, it was the best reward.
- wrs 4mo ago
  This is a way of using LLMs that doesn’t seem appreciated enough: prototyping a refactor or other new approach to see how it goes. Even if you then rewrite it from scratch, it’s a big timesaver because you’re using the new knowledge to do the “right thing” and avoid backtracking.
  - jadyoyster 4mo ago
    This is exactly how I use LLMs. "I wonder if it's possible to ...", and if I get something that seems to work or passes the test suite that gives me lots of added confidence that an approach is worth spending proper engineering time on. Or sometimes you get suggested a method or library you've never heard of, opening your horizons.
- mark_h 4mo ago
  I really appreciated this too. Such a contrast with a similar article from someone offended because their "honesty" caused a patch to be rejected.
internet_points 4mo ago
could've guessed staying away from xdisp.c was a good idea, cf. the "Buttery Smooth Emacs"[0] post: > Keep in mind that Emacs xdisp.c tries to support five different toolkits (including two different major versions of GTK) with #ifdefs. There is no runtime abstraction. We define three or four different versions of each damn function. It’s a nightmare. [0] https://gist.github.com/ghosty141/c93f21d6cd476417d4a9814eb71dd46e https://gist.github.com/ghosty141/c93f21d6cd476417d4a9814eb7...
- adrian_b 4mo ago
  "No runtime abstraction" seems the correct approach for good performance. Run-time abstractions should always be avoided when the problem can be solved at compile-time. While the conditional compilation syntax of the C/C++ preprocessor is not nice, good programming text editors can make it much more readable, by highlighting/hiding appropriate text sections.
simscitizen 4mo ago
I know this type of approach was rejected at the beginning, but you can also just ask CoreGraphics to use the GPU for 2D rendering (and I'm sure there are equivalent paths in e.g. Skia or Cairo). On macOS/iOS, the easiest way would probably be to set the drawsAsynchronously property on a CALayer. Then, all CoreGraphics operations on the context passed back to the layer via drawInContext: will be GPU accelerated. Lastly, there are some pretty sharp edges to this API, so definitely don't go flipping it on for every layer/view in your view hierarchy.
- Conscat 4mo ago
  This seems like the "obvious" solution. Why was the rejected? EDIT: It appears to be an objection to GPU programming entirely.
- andros 4mo ago
  There's a lot to discuss here, a very interesting comment. I wouldn't want to talk too much publicly about certain technical elements, and because I don't want to encourage solutions decided by LLMs, however the Skia/Cairo-GL angle is interesting but would be a heavy dependency and does not help Linux, where the same gfxterm.c policy drives the OpenGL backend. The vtable abstraction was specifically designed so the rendering logic is written once and the platform just supplies the draw primitives.
kleiba2 4mo ago
I'm more impressed that you managed to stream youtube - that seems to me like almost the more impressive feat.
- andros 4mo ago
  There's not much of a secret here; I used ffmpeg to pre-download the video—there's... no actual streaming. When you select a video, it downloads in parallel and starts playing. Sorry to disappoint you :)
jwr 4mo ago
Emacs user for >32 years now. It's a pity this won't get merged. There is a big usability/accessibility factor to consider here: I really wish I could have something like the Ghostty cursor_blaze.glsl shader for highlighting where the cursor is when you switch windows/buffers/apps. Most people think GPU equals silly toys like video in a text window, but there is much more to it than that. [and yes, I know about beacon, which unfortunately doesn't work too well, as well as about pulse, which I use]
- mickeyp 4mo ago
  GPU speedups are welcome, but you don't need a shader and a gpu to insert a flashy effect. Emacs has had this for decades: `pulse.el`. And building your own is very simple also. You'll still need someone to write the glue code to trigger the pulse, but then a gpu patch on the backend wouldn't give you that either. I'm sure someone on MELPA/Github has written code to do just this already.
  - iLemming 4mo ago
    > Emacs has had this for decades Pulse works, but honestly it pales when compared to neovim's effect. It would be nice to have a machinery to create things like that in Emacs.
  - jwr 4mo ago
    I expected this kind of reply, which is why I specifically mentioned that I actually use pulse. This attitude of "Emacs already has this" is not helpful and limits the development and evolution of Emacs. Have you seen how the Ghostty shaders work and how specifically the cursor highlighting one works? It is way better than what Emacs does today.
- iLemming 4mo ago
  I would love to have something like nvim's "smear-cursor". iirc someone wrote a patch (it was posted on r/emacs) - I'll attach it if I find it. My first thought was "is it doable as a dylib?"
- d-us-vb 4mo ago
flakiness 4mo ago
If I were you, it'd be pretty much worth it when you had a conversation with Stallman.
_f9cu 4mo ago
What is a backend for GPU?
- tmtvl 4mo ago
  A backend is a part of a program which receives commands from the frontend (the user-facing part of the program) and performs some actions based on the input received before sending the result back to the frontend. A GPU (graphics processing unit) is a piece of hardware which is very good at doing a lot of calculations with a lot of numbers very quickly. Making a backend for the GPU means programming the backend in such a way that it can run on the GPU, thereby (hopefully) getting the program to run faster and more efficiently.
asa123 4mo ago
Wow, I was just looking for something like this 15 minutes before you posted! Seems to not support Wayland though, from a quick scan, but cool project nonetheless
mickeyp 4mo ago
This is a really cool project. And it's so small, too, when you consider what it unlocks and the opportunities it creates. Really awesome!
lilactown 4mo ago
I tried to look for the thread on the emacs-devel archive, and couldn't find it. Is it not archived for some reason?
- tom_ 4mo ago
  https://lists.gnu.org/archive/html/emacs-devel/2026-06/msg00177.html https://lists.gnu.org/archive/html/emacs-devel/2026-06/msg00...
iLemming 4mo ago
Hey @d12frosted, would it be possible to have it as the emacs-plus (homebrew formula) option?
tomaskafka 4mo ago
"That was the moment the architecture stopped being a promise and became a fact." The post is AI generated as well, right?
- cml123 4mo ago
  it certainly has the tells... I could be charitable and say maybe since it's a bilingual blog it was generated as a type of translation from the original source, but that post itself seems only available in English
itomato 4mo ago
This should also compile to WASM, and support WebGPU, not that I’m advocating for it.
dharmatech 4mo ago
Andros is also the guy behind the really cool Org Social: https://org-social.org/ https://org-social.org/
- andros 4mo ago
  That's me!
stebalien 4mo ago
In case anyone is curious, ezemtsov (EWM author) has a Skai port of Emacs [1] built for Wayland (only). [1]: https://codeberg.org/ezemtsov/emacs https://codeberg.org/ezemtsov/emacs
devinprater 4mo ago
Holy crap does the visitors in realtime thing have to be a live region? Every sentence or two: "visitors in realtime party popper 8 weary cat face."
efti 4mo ago
Also done by master incal and his faithful sidekick cognitive efti, some time ago, with industry standard methods: Elisp/C/SDL3/OpenGL/GLSL/GPU. https://www.reddit.com/r/lisp/comments/1rasjwf/elgpu/ https://www.reddit.com/r/lisp/comments/1rasjwf/elgpu/ https://dataswamp.org/~incal/el-gpu/ https://dataswamp.org/~incal/el-gpu/ Big thread on devel as well also 'forgetting' to mention it eheh? Well, now then :)

193 points by andros 4mo ago

semessier 4mo ago

cudos

andros 4mo ago
Why?
- _f9cu 4mo ago
  What's the article talking about?
qrios 4mo ago
A new CUDA API? For DOS?
- saltcured 4mo ago
  No, CUDOS is using CUDA as your OS. What that has to do with this article about a new device driver for the EMACS OS, I don't quite know...

skydhash 4mo ago

This was almost a good read (a very good goal and a sensible approach), But the pacing of the article smells of LLM. I would suggest to do another pass at editing it out as it diminishes the story.

andros 4mo ago
If you've reached that conclusion, I'm truly proud of my writing technique. I'm sorry to say, though, that your instincts are failing you this time. I write my articles by hand over several days, although it's true that I do consult AI to improve my style, expressions, find synonyms, create tables, and correct spelling mistakes. Thank you for your comment!
- reinitctxoffset 4mo ago
  FWIW no one can tell anymore. Claude stopped doing all the LLM ticks like 6 months ago. There's a whole industry of people trying to detect LLM writing and they're getting stomped, this can be and is extremely well studied in the literature. The criticism is that you did something wildly ambitious and pulled it off. The blog is just well written.
  - tom_ 4mo ago
    People clearly can, though, because they did.
    - reinitctxoffset 4mo ago
      I'm inclined to believe the author, given that they were honest about the machine assist on the engineering? Why would they lie about the post and not the artifact? More broadly, I'm just getting tired of the low effort snark on this. If someone is going to cite a passage, or examples of a theme, do some serious analysis by all means. I'm not trying to tone police high effort comments. But this drive by "that's LLM output" thing is the new low effort "javascript is just as hard as c++" a.k.a "i don't know how to do that and i have no intention of learning and it feels bad so i'm going to lash out". Make a case that something is deficient on its merits or don't, but baseless accusations of dishonesty are not a reasonable default. The parent here did real work that no one paid them to do, donated it to the community asking nothing in return, it's meticulous and high value, and they've already been run over by the FSF goons, you really want to pile on with no evidence?
      - tom_ 4mo ago
        I'm inclined to believe them too, so when he said he used LLMs to tweak the wording, I'll accept that was the case. Perhaps the opening post was ill-phrased, but I think the second post clarifies it a bit: https://news.ycombinator.com/item?id=48677597 https://news.ycombinator.com/item?id=48677597 - and I was certainly getting some vague LLM vibes from the writing, so I was curious about this too. So, whatever it is in the LLM output that is detectable, it's clearly detectable, even with the latest LLMs, and even when it's present possibly only in trace quantities.
ghosty141 4mo ago
Very much this. I really dislike the somewhat corporate and characterless sounding tone of AI. I really liked the part where he tried to get it into upstream emacs, most of these type of projects never even get there. But yeah things like "bring honest numbers" sounds just weird.
- andros 4mo ago
  Please, have some mercy, English is not my first language! Thanks for the advice, I'll keep it in mind.
  - nh23423fefe 4mo ago
    dont listen to insane people obsessed with llm hatred. thanks for the article
  - ghosty141 4mo ago
    hey, honestly I personally wouldnt mind "unusual" english or some weird sentences. Obviously using AI to proofread and give suggestions is great use of it and I dont see a problem in that. Not a native speaker either so I can definitely relate :) I hope I didnt come off as too harsh, its just due to me seeing a lot of half-baked blog spam on r/emacs Ive gotten a bit sensitive when noticing AI writing.
  - green7ea 4mo ago
    People are paranoid that everything they read was written by a LLM. It's likely that they are even more suspicious because you used one to code. You should be proud of both the work you did and the article :-).
  - iLemming 4mo ago
    I honestly just don't get it. I feel people just whine for the sake of complaining about it, to get a feeling of some kind of moral superiority, or something. It's as if they're reading some GRR Martin kind of novel and the dragon slaying portrayal isn't up to their liking. It's not a fucking prose, learn how to extract useful information from a text, you're goddamn programmers, you've been mentally deciphering literal code, probably for a long fucking time, just fucking scan the text with your eyes and comprehend the meaning with your brain. If you don't like the style, just ask the LLM to summarize it for you, dang it. It's like if someone said: "your text appears to be typed in Emacs, sorry, but I won't read it. Try using a less controversial editor next time. Good effort though." Oh fuck you! Don't read it, who cares? Why come complaining about it? I feel like smacking them on the forehead, saying: "good job, you got me, I used AI, now what? Call the police, shoot me, cancel me, send complaints, clog my toilet..." Enormously annoying. More annoying that actually reading text written with AI assistance.

juancn 4mo ago

Doesn't just emacs render to a tty? Or is this for some Emacs build with its own renderer?

andros 4mo ago
This is for the GUI build of Emacs, not the terminal (tty) version. Emacs has had a native GUI renderer since the 90s, on macOS it uses Cocoa/NS, on Linux it uses GTK or raw X11. This project replaces that CPU-based drawing pipeline with a GPU backend: Metal on macOS and OpenGL/EGL on Linux. The tty build is unaffected.

sph 4mo ago

https://github.com/tanrax/emacs-gpu/blob/main/.github/assets/bench-linux-4k.png https://github.com/tanrax/emacs-gpu/blob/main/.github/assets... This massive speed-up on 4K screens makes me want to try it. The wayland pgtk version has such terrible latency I have to use the X11 build to avoid gnashing teeth during my working hours. And I think it's the X11 version that uses cairo, so the actual speedup in my case might be even larger. I reported the issue years ago, the pgtk maintainer confirmed, say they can't do much as they're using GTK3 which isn't hardware accelerated, so I have to wait until they migrate to GTK4 (in a decade or so). A bit disappointing, but that's open source. Looks like I'm not the only one suffering with a 4K screen: https://old.reddit.com/r/emacs/comments/ucv0at/awful_performance_with_pgtk_on_wayland/ https://old.reddit.com/r/emacs/comments/ucv0at/awful_perform...

andros 4mo ago
Good news on the Wayland front: there is already a working branch (wayland-pgtk-backend) that adds a PGTK binding on top of the same EGL/GLES driver, pending merge to main. If you want to try it before that, the branch is available on the repo.
- zeendo 4mo ago
  I can't find that branch here - https://cgit.git.savannah.gnu.org/cgit/emacs.git https://cgit.git.savannah.gnu.org/cgit/emacs.git Am I looking in the wrong place?
  - stebalien 4mo ago
    https://github.com/tanrax/emacs-gpu/tree/wayland-pgtk-backend https://github.com/tanrax/emacs-gpu/tree/wayland-pgtk-backen... The main emacs-gpu branch doesn't have wayland support.
    - zeendo 4mo ago
      Oh thanks! I thought they meant this was going on in the real emacs man.

drob518 4mo ago

Well done. Here’s hoping that a hand-written GPU backend gets developed based on this wonderful proof of concept. There’s no reason to not take advantage of the state of the art hardware when it’s available. And screens are only moving toward 4k and higher (6k or 8k).

andros 4mo ago
Me too. In the meantime, I'll stick with this version :)
joshjob42 4mo ago
Or that GNU updates a policy that will very rapidly go from probably net silly/mildly contestedly useful to completely ridiculous in a year or two. Not allowing LLM code will be basically turning down the work of the worlds best programmers running at 50x speed in couple years, and will functionally doom any software project that enforces such a policy.
- tom_ 4mo ago
  We shall see.
- vlian2088 4mo ago
  that policy should only ever be relaxed towards legacy contributors and those they can vouch for. otherwise, allowing sloptributions opens the gates to a myriad you-know-who who used to submit pull requests for ESL rewrite of two sequences in README.md and now submit chatgpt-generated refactors - which waste even more human time - just so they can proudly put "open source contributor" on their resumes.
- agentultra 4mo ago
  Doubt that. If you couldn’t write it yourself you can’t get an LLM to do it for you. So unless you’re attracting the 50 best software developers you’re getting middling to miserable results.
- deleted 4mo ago
  [deleted]

bingemaker 4mo ago

Great work! Possible to have a patch that I can apply on 32.0.5 and try this out?

andros 4mo ago
Yes, of course, I worked with the develop version until at a certain point I decided to downgrade to the stable versions. I'll be releasing more versions later; I'm still focused on fixing minor issues in Linux.

_doctor_love 4mo ago

This is the way! Very nice work. I want it!

andros 4mo ago
Thank you!

bjourne 4mo ago

Cool! Regardless of whether your code gets merged, it shows that xdisp.c can be tamed. Like Roger Bannister who ran the miracle mile, you showed that it can be done. Hopefully more will chip in and slay the Emacs redisplay code beast.

andros 4mo ago
Thank you, this means a lot!

reinitctxoffset 4mo ago

This is outstanding, if I have time I'll be switching over today. This is the kind of thing that could drive a truly free fork of emacs forward, it's enough better on realistic desktop displays to rally around and as the parent discovered "Free Software" at this point has very little to do with the freedom to do what I want on my computer in a low friction way: an ideological position on "GPUs" as a category is bizarre even by Late Soviet FSF standards. By all means cite a vendor and a policy, but even NVIDIA is in tree now, it's got the same software freedom as ext4 and I don't hear anyone talking about chains on that. In the age of machine assist emacs could get a modern fast/cachable build, clean under all the sanitizers, io_uring on Linux, deterministic clang formatting, compat break with zero-use junk from the 80s, WASM compilation for polyglot extension (I like lisp but I understand why some people don't), modern networking, modern chrome, 100% vscode compatible LSP, modern theming that defaults to something that doesn't drive users away. I would love to have a ten line init.el instead of 4k of workarounds. Maybe this can be the nvim moment. I love emacs but the nvim people have so many nice things and FSF emacs has a shelf life. If someone out of their own time and resources did a cross platform, mechanically verified, dramatically accelerated at HiDPI patch to basically anything else they'd be greeted like a hero. Keep up the good work legend.

andros 4mo ago
Thank you! A small correction on framing though: the goal is not a fork but a patch upstream. The backend is structured precisely to minimize the diff against Emacs mainline. The "nvim moment" comparison is flattering but I would rather this be the patch that makes the FSF argument easier to win than the one that splits the community. That said, your list of modernization items is a fair read of the backlog.
arikrahman 4mo ago
I agree. Nvim already takes notes out of emacs with major contributors using Funnel to use Lisp as a workaround for working with Lua. This would be a step in the right direction for the continued pioneer emacs proves to be.
wasting_time 4mo ago
Just to clarify: the NVIDIA driver is not in-tree, and probably never will be. Intel and AMD are, but require proprietary firmware to work, so the freedom aspect is disputed.

abstractbg 4mo ago

Interesting improvement. My biggest issue with Emacs and the reason that I left it was because it was not multi-threaded. I wonder if is/can be multi-threaded now.

andros 4mo ago
You have libraries for multithreading. I use them myself for parallel tasks. However, how events and redrawing work is a completely different matter.
skydhash 4mo ago
Concurrency is a source of many bugs and complexity. Emacs have a few async mechanisms and they’re good enough for most tasks. The async nature of other editors does not really matter as you’re still waiting for actions to complete.
iLemming 4mo ago
> because it was not multi-threaded I'm honestly curious, what kind of multi-threading you use, in whatever you're using now instead of Emacs? Can you share some practical example(s)? I'm not trying to trick you, I'm just curious for what kind of complex tasks possible there and where Emacs comes short.
- tmtvl 4mo ago
  Curious that your comment was dead for whatever reason. I vouched for you because I'm also curious at what a user would need concurrency for in a text editor (I mean, granted, Emacs is a Lisp implementation with an amazing text editor attached so in theory someone may want concurrency for programming something in Elisp).
  - andros 4mo ago
    To avoid UI freezes, separate event processing from rendering (for example). It's very common to see the interface freeze while a complex command is running.
- 4mo ago

arikrahman 4mo ago

Aside from the wonderful contribution to Emacs, I have the utmost respect for how straight-forward you were with the 100% LLM generated code. The enlightening conversation on GPU freedom that ensued was also informative.

andros 4mo ago
I completely agree with you. For me, it was the best reward.
wrs 4mo ago
This is a way of using LLMs that doesn’t seem appreciated enough: prototyping a refactor or other new approach to see how it goes. Even if you then rewrite it from scratch, it’s a big timesaver because you’re using the new knowledge to do the “right thing” and avoid backtracking.
- jadyoyster 4mo ago
  This is exactly how I use LLMs. "I wonder if it's possible to ...", and if I get something that seems to work or passes the test suite that gives me lots of added confidence that an approach is worth spending proper engineering time on. Or sometimes you get suggested a method or library you've never heard of, opening your horizons.
mark_h 4mo ago
I really appreciated this too. Such a contrast with a similar article from someone offended because their "honesty" caused a patch to be rejected.

internet_points 4mo ago

could've guessed staying away from xdisp.c was a good idea, cf. the "Buttery Smooth Emacs"[0] post: > Keep in mind that Emacs xdisp.c tries to support five different toolkits (including two different major versions of GTK) with #ifdefs. There is no runtime abstraction. We define three or four different versions of each damn function. It’s a nightmare. [0] https://gist.github.com/ghosty141/c93f21d6cd476417d4a9814eb71dd46e https://gist.github.com/ghosty141/c93f21d6cd476417d4a9814eb7...

adrian_b 4mo ago
"No runtime abstraction" seems the correct approach for good performance. Run-time abstractions should always be avoided when the problem can be solved at compile-time. While the conditional compilation syntax of the C/C++ preprocessor is not nice, good programming text editors can make it much more readable, by highlighting/hiding appropriate text sections.

simscitizen 4mo ago

I know this type of approach was rejected at the beginning, but you can also just ask CoreGraphics to use the GPU for 2D rendering (and I'm sure there are equivalent paths in e.g. Skia or Cairo). On macOS/iOS, the easiest way would probably be to set the drawsAsynchronously property on a CALayer. Then, all CoreGraphics operations on the context passed back to the layer via drawInContext: will be GPU accelerated. Lastly, there are some pretty sharp edges to this API, so definitely don't go flipping it on for every layer/view in your view hierarchy.

Conscat 4mo ago
This seems like the "obvious" solution. Why was the rejected? EDIT: It appears to be an objection to GPU programming entirely.
andros 4mo ago
There's a lot to discuss here, a very interesting comment. I wouldn't want to talk too much publicly about certain technical elements, and because I don't want to encourage solutions decided by LLMs, however the Skia/Cairo-GL angle is interesting but would be a heavy dependency and does not help Linux, where the same gfxterm.c policy drives the OpenGL backend. The vtable abstraction was specifically designed so the rendering logic is written once and the platform just supplies the draw primitives.

kleiba2 4mo ago

I'm more impressed that you managed to stream youtube - that seems to me like almost the more impressive feat.

andros 4mo ago
There's not much of a secret here; I used ffmpeg to pre-download the video—there's... no actual streaming. When you select a video, it downloads in parallel and starts playing. Sorry to disappoint you :)

jwr 4mo ago

Emacs user for >32 years now. It's a pity this won't get merged. There is a big usability/accessibility factor to consider here: I really wish I could have something like the Ghostty cursor_blaze.glsl shader for highlighting where the cursor is when you switch windows/buffers/apps. Most people think GPU equals silly toys like video in a text window, but there is much more to it than that. [and yes, I know about beacon, which unfortunately doesn't work too well, as well as about pulse, which I use]

mickeyp 4mo ago
GPU speedups are welcome, but you don't need a shader and a gpu to insert a flashy effect. Emacs has had this for decades: `pulse.el`. And building your own is very simple also. You'll still need someone to write the glue code to trigger the pulse, but then a gpu patch on the backend wouldn't give you that either. I'm sure someone on MELPA/Github has written code to do just this already.
- iLemming 4mo ago
  > Emacs has had this for decades Pulse works, but honestly it pales when compared to neovim's effect. It would be nice to have a machinery to create things like that in Emacs.
- jwr 4mo ago
  I expected this kind of reply, which is why I specifically mentioned that I actually use pulse. This attitude of "Emacs already has this" is not helpful and limits the development and evolution of Emacs. Have you seen how the Ghostty shaders work and how specifically the cursor highlighting one works? It is way better than what Emacs does today.
iLemming 4mo ago
I would love to have something like nvim's "smear-cursor". iirc someone wrote a patch (it was posted on r/emacs) - I'll attach it if I find it. My first thought was "is it doable as a dylib?"
d-us-vb 4mo ago

flakiness 4mo ago

If I were you, it'd be pretty much worth it when you had a conversation with Stallman.

_f9cu 4mo ago

What is a backend for GPU?

tmtvl 4mo ago
A backend is a part of a program which receives commands from the frontend (the user-facing part of the program) and performs some actions based on the input received before sending the result back to the frontend. A GPU (graphics processing unit) is a piece of hardware which is very good at doing a lot of calculations with a lot of numbers very quickly. Making a backend for the GPU means programming the backend in such a way that it can run on the GPU, thereby (hopefully) getting the program to run faster and more efficiently.

asa123 4mo ago

Wow, I was just looking for something like this 15 minutes before you posted! Seems to not support Wayland though, from a quick scan, but cool project nonetheless

mickeyp 4mo ago

This is a really cool project. And it's so small, too, when you consider what it unlocks and the opportunities it creates. Really awesome!

lilactown 4mo ago

I tried to look for the thread on the emacs-devel archive, and couldn't find it. Is it not archived for some reason?

tom_ 4mo ago
https://lists.gnu.org/archive/html/emacs-devel/2026-06/msg00177.html https://lists.gnu.org/archive/html/emacs-devel/2026-06/msg00...

iLemming 4mo ago

Hey @d12frosted, would it be possible to have it as the emacs-plus (homebrew formula) option?

tomaskafka 4mo ago

"That was the moment the architecture stopped being a promise and became a fact." The post is AI generated as well, right?

cml123 4mo ago
it certainly has the tells... I could be charitable and say maybe since it's a bilingual blog it was generated as a type of translation from the original source, but that post itself seems only available in English

itomato 4mo ago

This should also compile to WASM, and support WebGPU, not that I’m advocating for it.

dharmatech 4mo ago

Andros is also the guy behind the really cool Org Social: https://org-social.org/ https://org-social.org/

andros 4mo ago
That's me!

stebalien 4mo ago

In case anyone is curious, ezemtsov (EWM author) has a Skai port of Emacs [1] built for Wayland (only). [1]: https://codeberg.org/ezemtsov/emacs https://codeberg.org/ezemtsov/emacs

devinprater 4mo ago

Holy crap does the visitors in realtime thing have to be a live region? Every sentence or two: "visitors in realtime party popper 8 weary cat face."

efti 4mo ago

Also done by master incal and his faithful sidekick cognitive efti, some time ago, with industry standard methods: Elisp/C/SDL3/OpenGL/GLSL/GPU. https://www.reddit.com/r/lisp/comments/1rasjwf/elgpu/ https://www.reddit.com/r/lisp/comments/1rasjwf/elgpu/ https://dataswamp.org/~incal/el-gpu/ https://dataswamp.org/~incal/el-gpu/ Big thread on devel as well also 'forgetting' to mention it eheh? Well, now then :)