Hard numbers in the Wayland vs. X11 input latency discussion

Protocols can bake in unfortunate performance implications simply by virtue of defining an interface that doesn't fit the shape needed for good performance. Furthermore, this tends to happen "by default" unless there is a strong voice for performance in the design process.

Hopefully this general concern doesn't apply to Wayland and the "shape" you have described doesn't sound bad, but the devil is in the details.

Software works best when the developers take responsibility for solving user's problems.

> Wayland, which is a protocol

This is wayland's biggest weakness. The effect is diffusion of responsibility.

Wayland as a just protocol... Isn't that the same argument they used when it shipped without copy/paste or a screensaver?

> The trickery starts when dragging windows or icons around

Cool. Never really thought about why they don't exactly keep up with the cursor.

This isn't about in-game performance, this is about the desktop feeling sluggish.

I'm not sure where this absolute "tearing is bad" and "correctness" mentality comes from. To me, the "correct" thing specifically for the mouse cursor is to minimize input lag. Avoiding tearing is for content. A moving cursor is in various places along the screen anyway, which will include biological "afterglow" in one's eyes and therefore there's going to be some ghosted perception of the cursor anyway. Tearing the cursor just adds another ghost. And at the same time, this ghosting is the reason keeping cursor input lag to a minimum is so important, to keep the brain's hand-eye coordination in sync with the laggy display.

That is a great comment and everyone should read it. It also demonstrates a common truism that system goals dictate performance.

Tl;dr: X bad and tears but Wayland with 1.5 frame latency (or more) good. Now, if you have a monitor (or TV) with 30i refresh rate, you're screwed.

On sway, if you use the proprietary Nvidia drivers, it is often necessary to disable hardware cursors. I wonder if there is something similar happening here. Maybe wayland gnome doesn't use hardware cursors?

Or later, seeing how long it took to load /usr/bin in a filemanager.

Wayland is a protocol. The problems people complain about are generally implementation details specific to GNOME or KDE or (in general) one particular implementation.

There's rarely any such thing as "universal superiority", usually you're making a tradeoff. In the case of X vs Wayland it's usually latency vs. tearing. Personally I'm happy with Wayland because there was a time when watching certain videos with certain media players on Linux was incredibly painful because of how blatant and obtrusive the tearing was. Watching the same video under Wayland worked fine.

Early automobiles didn't have "universal superiority" to horses, but that wasn't an inhibitor to adoption.

> How old is Wayland?

About 16 years old, for comparison, X is 40.

>How old is Wayland?

This argument don't make sense because Wayland started as a hobby and not to replace x11, was after it got traction, other people/companies started contributing that it matter

> Wayland adoption should have been predicated on a near universal superiority in all input and display requirements.

Totally agree. The people saying "Wayland is a protocol" miss the point. Wayland is a protocol, but Wayland adoption means implementing stuff that uses that protocol, and then pushing it onto users.

Measure twice, cut once. Look before you leap. All that kind of thing. Get it working FIRST, then release it.

> Wayland simply came at a time to further the delay of the Linux desktop

I can't tell if you are serious or not.

>but this is a forced change for the worse for so long

Can you explain who is forced to do what in that context?

> I understand I'm complaining about free things, but this is a forced change for the worse for so long.

Then write code.

Asahi Lina has demonstrated that a single person can write the appropriate shims to make things work.

Vulkan being effectively universally available on all the Linux graphics cards means that you have the hardest layer of abstraction to the GPU taken care of.

A single or small number of people could write a layer that sits above Wayland and X11 and does it right. However, no one has.

You're arguing against Wayland, but for a more secure Linux desktop? I recommend you spend more time getting to know the X11 protocol then, because it has plenty of design decisions that simply cannot be secured. The same people who used to develop XFree86 designed Wayland to fix things that could not be fixed in the scope of X11.

To have a compositor not introduce a frame of latency more or less requires it to race the beam, which has definitely been suggested[1], but you can see how it’d be difficult, and so far no operating systems have tried as far as I know. And as for good frame pacing support in UI toolkits (and not just game engines), well, one can dream. Until both of these are in place, 2.5±0.5 seems to be the hard limit, the question here is more where the Mutter is losing another frame (which even the greats tell us[2] is not hard to do by accident).

[1] https://raphlinus.github.io/ui/graphics/2020/09/13/composito...

[2] http://number-none.com/blow/john_carmack_on_inlined_code.htm...

I was pretty shocked by the eyestrain difference I felt going from 30hz to 60hz with a 4K monitor while only doing coding tasks (i.e. text and mouse, no real graphics or animations).

what would you count as low latency terminal?

I enjoy reading the whinging around Wayland by people who feel so entitled and so outraged. Every time they never fail to remind me of a previous coworker who was always using the same tactics: « this breaks my existing workflow, I will not adapt, I am all for trying new things but only if they are very exactly equal to what I already know and then what's the point, this is not how I have always worked the past ten years and I will not bulge ».

Not talking about the technical points of the whole X/Wayland considerations here, but a group of people in such debate is always as vocal as they'll do nothing and put unreasonably high expectations on other people to listen to them and have no choice but to agree. The fact that X.org's core team initiated Wayland and stopped X.org development is disregarded: these people Will Be Right against literally everything, they can't be reasoned.

My previous coworker was fired for gross incompetence in the end yet he never acknowledged anything wrong. He always knew better than literally the whole world that bash scripts run manually where superior to Terraform for the whole company's infrastructure. Yes, he was that stupid. I guess this is why he ended lying like hell on his LinkedIn profile, concealing he had had four employers in four years.

Seeing technical debates with such poor quality is worrying. If people with quantitative minds fail to entertain a fact-based discussion, how can we expect our political life to acknowledge there is only one reality and stop lying?

Before you voice your outrage, here are some facts that won't dis-exist just because you disagree with them:

- https://www.phoronix.com/review/x_wayland_situation

- https://ajaxnwnk.blogspot.com/2020/10/on-abandoning-x-server...

> Approximately 99.999% of those complaints are uttered by people who 1) are not doing the work, 2) are not interested or capable of doing the work, and

Are you saying that Wayland is only for developers? Are people not allowed to complain when The New Thing turns out to be less good than the supposedly Obsolete Thing?

> 3) do not understand or refuse to acknowledge that the Wayland and X developers are _mostly the same folks_ and they _do not want to work on X11 anymore_.

I'm fully aware of that. I understand X11 has its limitations, and some of the goals of Wayland sound very appropriate for the modern PC environment, but if after 16 years, there are still many situations where Wayland does worse than X, that's not a great sign, and it will make people continue to use X.

> There are enough Wayland whiners that, by now, they could've banded together and started maintaining / improving X and (if their complaints and theories were correct) left Wayland behind.

They already have. X is already more full-featured and stable than Wayland (yes it is missing certain niche features that Wayland has). Sometimes the most important thing you can do with a piece of software is not screw around with it.

> what they often mean is "Wayland doesn't support $very_specific_feature"

My primary complaint with Wayland is that it is a textbook example of Brooks’s second-system effect. It forsook backwards compatibility (yes, there’s an X11 server but to my knowledge there is no way to just run Wayland and one’s X11 desktop environment).

> Strangely -- even though X is open source and eminently forkable (we know this, because XFree86 -> X.org) it gathers dust and none of its proponents are doing anything towards its upkeep.

I suspect that is because the X/Wayland guys have sucked all the oxygen out of that particular room. A newbie shows up and is told that X.org is legacy and he shouldn’t work on it, so … he doesn’t.

And of course X.org really is a bit of a disaster due to being written in C.

The core Wayland and X.org don't exist in a vacuum. I have written a lot of code over the years that works only on X, as have many others. I have not directly contributed to the X.org server, but have to the "wider X ecosystem". I will have to rewrite some of that. This is the case for many people.

> When people complain about Wayland being mediocre or "as good as X was" what they often mean is "Wayland doesn't support $very_specific_feature" or "my video card vendor's proprietary drivers aren't well-tested with Wayland and it makes me sad".

...Yes? Wayland being a regression in terms of features and bugginess is kinda a sticking point.

> Approximately 99.999% of those complaints are uttered by people who 1) are not doing the work, 2) are not interested or capable of doing the work, and 3) do not understand or refuse to acknowledge that the Wayland and X developers are _mostly the same folks_ and they _do not want to work on X11 anymore_.

If X works for someone and Wayland doesn't, none of that matters. It doesn't matter how much you insult X users, it won't make their usecases invalid or make Wayland good enough.

> I don't really have a stake in this argument, except I'm bone-tired of seeing people whine about Wayland when they're using software somebody else gave them for free.

It cuts both ways: Users aren't entitled to free work, and developers aren't entitled to their work being well-regarded. Giving software away for free has never meant that people can't point out its problems.

That means in two more years it will be legal for X11 and Wayland to have a baby!

Same here, switching from i3 to sway resulted in a noticeably more responsive experience on my aging hardware. Of course, this is just an anecdote, and I could probably get the same results on X with some fiddling, but I do think the value of simpler and more modern systems is demonstrated here.

????

After upgrading to plasma6 from 5, all the desktop animations have started stuttering. Probably your hardware is too new.

On the other hand, I just did a fresh install of Artix Linux. Installed KDE just to have something functional while I get my tiling setup working. Boot into Plasma(Wayland) and it utterly shits itself, turning my main monitor on and off repeatedly until it finally crashes. So I pick Plasma(X11) instead and that just works.

In fact, in almost 2 decades of using Linux every day, I can't remember X doing anything similar. It's always just worked.

Less latency matters little if it's just to wait behind some other operation like disk IO or network.

I can also attest to horrific lagspikes on an Optimus laptop even if Intel is driving the desktop. Memory pressure is definitely the problem here. Lagspikes actually lessened when I switched to Wayland Gnome. I think they lessened further with PREEMPT_RT on kernel 6.12. Nvidia requires an environment variable to build on real time kernels but it plays surprisingly nice as of driver 570. But if you have this config, you need at least 11th gen Intel iGPU or AMD APU, because i915 does not build for real-time kernels. Only the Xe driver works and only if you force_probe the ID if it's Tiger Lake.

...Which I don't get because the Xe driver is said to explicitly support, at minimum, Tiger Lake. I played Minecraft on the iGPU with Xe and it was perfectly fine. It... drew 3D graphics at expected framerates.