On Fri, Apr 17, 2015 at 4:06 PM, Matt Hoosier <[email protected]> wrote: > On Fri, Apr 17, 2015 at 12:22 PM, Lennart Poettering > <[email protected]> wrote: >> >> On Fri, 17.04.15 09:00, Matt Hoosier ([email protected]) wrote: >> >> > Hi, >> > >> > I'm writing to see whether there's a "best" way to allow systemd to >> > inherit >> > ownership of a process forked from a hand-crafted /sbin/init process >> > before >> > that hand-crafted process turns over the keys to systemd by doing >> > exec("/lib/systemd/systemd") over the top of itself and allowing it to >> > take >> > over as PID 1. >> >> We support this only really for "kernel-like" processes that are >> started from the initrd, and basically run as long as the system is up >> without every being restarted in between, thus effectively appearing >> much like a kernel process and nothing systemd should >> manage. Processes like this should be marked with argv[0][0] = '@', >> see for details: >> >> https://wiki.freedesktop.org/www/Software/systemd/RootStorageDaemons/ >> >> > I know that sounds like an odd thing to ask about. The use-case has to >> > do >> > with being able to start some work extremely early during boot of >> > embedded >> > systems to achieve performance goals. I don't wish to subvert systemd, >> > and >> > in fact would love for systemd to be able to monitor the process, stop >> > it, >> > restart according to the normal [Service] configuration in a unit file >> > describing the process. >> >> Hmm, are you sure that invoking the binary from systemd as first >> service is really that much slower than starting systemd only afterwards? > > > The bootcharting that I do seems to show that about 1.2 - 1.5 sec are spent > internal to systemd before any external processes get run for the particular > embedded CPU I'm using. That gap is a killer at the moment.
Did you watch this presentation ? https://www.youtube.com/watch?v=RFVlbaDqll8 what part of systemd is taking 1.5 seconds to start, on what CPU and how much of RAM does the board has ? _______________________________________________ systemd-devel mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/systemd-devel
