On Tue, 18.06.13 09:11, Daniel J Walsh (dwa...@redhat.com) wrote: > One concern we have is what will happen to systemd if we start 1000 services > at boot. > > systemctl start httpd_sandbox.target > > For example. > > Is there anything we can do to throttle the start of so many unit files. Or > would systemd do something itself.
So, we have rate limits on some things. We maintain per-service ratelimits, and a ratelimit in the main even loop. However, that's really just a last resort thing. Basically, if the event loop spins more often than 50.000 times per second we will just totally block execution for 1s. So things get awfully slow when we do too much stuff so that we don't consumer 100% CPU forever, and that's all. I have no experience with running this many services on a machine. I am sure we can add various bits here and there to make sure things scale nicely for this. But for that I'd really like some performance data first, i.e. what actually really happens with the current code. Also, let me get this right: this is about not overloading the kernel with starting up too many processes at the same time? Is this really a problem? I figured our kernel these days wouldn't have much problems with loads like this... We have a queue of jobs we need to execute. This jobs basically map to processes we start. We could certainly add something that throttles dispatching of this queue if we dispatch too many of them in a short time. With such an approach we'd continue to run the main event loop as normal, but simply pause processing of the job queue for a while. Lennart -- Lennart Poettering - Red Hat, Inc. _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
