[lemagedurage]

A "few extra ms" is up to 3 roundtrips difference, that's easily noticeable by humans on cellular.

For all the CPU optimisations we're doing, cutting out a 50ms roundtrip for establishing a HTTP connection feels like a great area to optimize performance.

[motorest]

> A "few extra ms" is up to 3 roundtrips difference, that's easily noticeable by humans on cellular.

That's a valid concern. That's the baseline already though, so everyone is already living with that without much in the way of a concern. It's a nice-to-have.

The problem OP presents is what are the tradeoffs for that nice-to-have. Is security holes an acceptable tradeoff?

[IgorPartola]

I routinely have concerns about lag on mobile. It sucks to have to wait for 10 seconds for a basic app to load. And that adds up over the many many users any given app or website has.

[fragmede]

Most people still use Google, and so they're living the fast HTTP 3 life, switching off that to a slower protocol only when interacting with non-Google/Amazon/MSFT properties. If your product is a competitor, but slower/inaccessible users are going to bounce off your product and not even be able to tell you why.

[croes]

And then the web app eats all that saved ms with ease.

[guappa]

Does it really matter? The website is first going to download 5mb of js, then it's going to show 3 popups.

[the8472]

Isn't 5G supposed to solve the mobile latency issue?

[nine_k]

The connection to your local tower can have a negligible latency. The connection all the way to the datacenter may take longer. Then, there is congestion sometimes, e.g. around large gatherings of people; it manifests as latency, too.

[KaiserPro]

> Isn't 5G supposed to solve the mobile latency issue?

Kinda.

So 5g is faster, but its still wireless, and shared spectrum. This means that the more people that use it, or the further they are away, the speed and bandwidth per client is adjusted.

(I'm not sure of the coding scheme for 5G, so take this with caution) For mobiles that are further away, or have a higher noise floor, the symbol rate (ie the number of radiowave "bits" that are being sent) is reduced so that there is a high chance they will be understood at the other end (Shannon's law, or something) Like in wifi, as the signal gets weaker, the headline connection speed drops from 100mb+ to 11.

In wifi, that tends to degrade the whole AP's performance, in 5G I'm not sure.

Either way, a bad connection will give you dropped packets.

[TheRealPomax]

And yet, compared to the time you're waiting for that mast head jpeg to load, plus an even bigger "react app bundle", also completely irrelevant.

HTTP/3 makes a meaningful difference for machines that need to work with HTTP endpoints, which is what Google needed it for: it will save them (and any other web based system similar to theirs) tons of time and bandwidth, which at their scale directly translates to dollars saved. But it makes no overall difference to individual humans who are loading a web page or web app.

There's a good argument to be made about wasting round trips and HTTP/3 adoption fixing that, but it's not grounded in the human experience, because the human experience isn't going to notice it and go "...did something change? everything feels so much faster now".

[charleslmunger]

Deploying QUIC led to substantial p95 and p99 latency improvements when I did it (admittedly a long time ago) in some widely used mobile apps. At first we had to correct our analysis for connection success rate because so many previously failing connections now succeeded slowly.

It's a material benefit over networks with packet loss and/or high latency. An individual human trying to accomplish something in an elevator, parking garage, or crowded venue will care about a connection being faster with a greater likelihood of success.

[celsoazevedo]

Almost every optimization is irrelevant if we apply the same reasoning to everything. Add all savings together and it does make a difference to real people using the web in the real world.

[epolanski]

> But it makes no overall difference to individual humans who are loading a web page or web app.

Navigating from my phone at 4g and my fiber connection has drastic differences.

Especially noticeable when on vacations or places with poor connections, TLS handshakes can take many, many, many, seconds..After the handshake and an established connection it's very different.