Re: [libmicrohttpd] unexpected "Server reached connection limit." failures

[Frank Ch. Eigler]

Evgeny Grin wrote:

> Could you share your MHD flags, options, and commands you use to
> measure MHD load?

That could be tough, but see git://sourceware.org/git/elfutils.git
debuginfod/debuginfod.cxx.  The key bits appear to be:

- cgroups/ulimits impose a limit of a small number of tasks (threads)
- THREAD_PER_CONNECTION mode
- a http service callback that takes enough time to build up some
  concurrency, maybe just a sleep(10)
- then hit it with enough concurrent load to exceed the limits on tasks,
  so MHD_create_named_thread_() fails a bunch of times
- then ease the load rate back to nothing
- but observe that daemon->connections remains way above zero, maybe >1000
- and then even mild load starts getting rejected with the $subject error


- FChE