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Comment by ronsor | Hacker News Reader

The fact that we need advanced GPU acceleration for a text editor is concerning.

Such is life when built-in laptop displays are now pushing a billion pixels per second, rendering anything on the CPU adds up fast.

Sublime Text spent over a decade tuning their CPU renderer and it still didn't cut it at high resolutions.

https://www.sublimetext.com/blog/articles/hardware-accelerat...

Most of the pixels don't change every second though. Compositors do have damage tracking APIs, so you only need to render that which changed. Scrolling can be mostly offset transforms (browsers do that, they'd be unbearably slow otherwise).

That’s not the slow part. The slow part is moving any data at all to the GPU - doesn’t super matter if it’s a megabyte or a kilobyte. And you need it there anyway, because that’s what the display is attached to.

Now, the situation is that your display is directly attached to a humongously overpowered beefcake of a coprocessor (the GPU), which is hyper-optimized for calculating pixel stuff, and it can do it orders of magnitude faster than you can tell it manually how to update even a single pixel.

Not using it is silly when you look at it that way.

Sure, use it. But it very much shouldn't be needed, and if there's a bug keeping you from using it your performance outside video games should still be fine. Your average new frame only changes a couple pixels, and a CPU can copy rectangles at full memory speed.

I'm kinda weirded out by the fact that their renderer takes 3ms on a desktop graphics card that is capable of rendering way more demanding 3D scenes in a video game.

I have no problem with it squeezing out the last few percent using the GPU.

But look at my CPU charts in the github link upthread. I understand that maybe that's due to the CPU emulating a GPU? But from a thousand feet, that's not viable for a text editor.

Yeah LLVMpipe means it's emulating the GPU path on the CPU, which is really not what you want. What GPU do you have out of interest? You have to go back pretty far to find something which doesn't support Vulkan at all, it's possible that you do have Vulkan but not the feature set Zed currently expects.

It was ASUS GeForce GT710-SL-2GD5 . I see some sources putting at at 2014. That's not _recent_ recent, but it's within the service life I'd expect.

(Finger in the air, I'd expect an editor to work on 20 year old hardware.)

Sold it ages ago. New one (Intel) works fine.

I was running Ubuntu. I forget which version.

> It was ASUS GeForce GT710-SL-2GD5 . I see some sources putting at at 2014. That's not _recent_ recent, but it's within the service life I'd expect.

That's pretty old, the actual architecture debuted in 2012 and Nvidia stopped supporting the official drivers in 2021. Technically it did barely support Vulkan, but with that much legacy baggage it's not really surprising that greenfield Vulkan software doesn't work on it. In any case you should be set for a long time with that new Intel card.

I get where you're coming from that it's just a text editor, but on the other hand what they're doing is optimal for most of their users, and it would be a lot of extra work to also support the long tail of hardware which is almost old enough to vote.

I initially misremembered the age of the card, but it was about that old when I bought it.

My hope was that they would find a higher-level place to modularize the render than llvmpipe, although I agree that was unreasonable technical choice.

Once-in-a-generation technology cliff-edges have to happen. Hopefully not too often. It's just not pleasant being caught on the wrong side of the cliff!

Thanks for the insights.

Text editor developers get bored too!

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