[preseinger]

Speed is the only reason CGI doesn't fly.

What do you think is the upper limit of requests per second, if your HTTP server does process-per-request? For simplicity, assume server class hardware, that each request does no work besides producing a response, and an upper bound of 10k unique remote addresses (i.e. no more than 10k concurrent connections in a different model).

How do you think those metrics compare to other designs? I have an affinity for the conceptual simplicity of CGI but I've never been able to get a process-per-request server within even an order of magnitude of the performance of the more common designs. But I could be missing something!

Also, how does this design adapt to HTTP/2?

[rakoo]

> What do you think is the upper limit of requests per second, if your HTTP server does process-per-request ?

In the hundreds, which is absolutely enough for most use cases. If CGI is enough for sqlite.org displaying dynamic content (such as in https://www.sqlite.org/cgi/src/timeline), it is enough for 80% of websites. You are not bigger than sqlite.

> How do you think those metrics compare to other designs

The important question is not "is it better or worse than alternatives" but "is it enough for me". Yes, it is.

> Also, how does this design adapt to HTTP/2?

HTTP/2 doesn't change anything. Requests are on the same socket until the webserver, and the webserver forks a process for each request, multiplexes the responses and all is well.

[preseinger]

> The important question is not "is it better or worse than alternatives" but "is it enough for me". Yes, it is.

All good! But if you're OK with O(100) RPS out of a server, then I guess basically every possible option is on the table. I bet `nc` spawning background `bash` scripts to handle requests would get to 1k RPS, even! ;)

> HTTP/2 doesn't change anything.

I guess that would work, as long as the fronting server managed all of the connection management details, stream demuxing, etc. But I wonder how you'd do that in a single thread?

[lelanthran]

> Speed is the only reason CGI doesn't fly.

It is indeed very very slow; mostly because it is not possible to pre-fork your CGI scripts (environment variables get set from the request, so each cgi program will have different values in the environment).

But, if you could pass HTTP data via some way other than environment variables, you could pre-fork the binaries and have acceptable speed[1].

[1] Pre-forking makes a large difference, and surprisingly is not too far off from other approaches to concurrent request handling. See https://unixism.net/2019/04/linux-applications-performance-i...

[preseinger]

Your link benchmarks with ab, which unfortunately has an unsound concurrency model, so you can't put too much trust in its results.