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

[Evgeny Grin]

Thanks for precise description and code analysis, Frank.

The issue (and a couple of connected issues) has been fixed in git master.

Could you build MHD from git sources and check whether the issue is 
fixed for you?

Thanks in advance.

--
Evgeny

On 04.12.2021 21:56, Frank Ch. Eigler wrote:
> 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