Le vendredi 28 mars 2014 à 12:12 -0500, Brandon Black a écrit : > > Hi all, > I've brought this up before, but I became busy/discouraged and > dropped the ball. As systemd becomes increasingly widely deployed, I > can no longer afford to do so, so I'd like to explore this area a bit > further on the list again and see if we can't come up with a workable > solution, or if perhaps I've missed some systemd/cgroups change in the > past year or so that already allows a workaround. > > [.. snip .. ] > > 4) Socket Activation! I know this is what some will scream when they > skim the above, but it's not a realistic solution in this case for a > few reasons: > a) The startup delay, in some cases, can be many whole wallclock > seconds. This is necessary and acceptable in the general sense (this > is network service that people use with large server-side > installations, not a desktop thing).
It only occurs on the first start, no ? > b) The primary socket traffic we care about is UDP, and further we > *really* care about request->response latency for this traffic. Even > if you could set a large enough receive buffer to handle several > seconds of heavy UDP requests (and you can't, for at least some > installations), the multi-second-delay in the responses isn't > reasonable. Again, that's a multiple second delay only for the first start, after, this will be the regular way since the socket is directly used by the daemon. > c) Another side-point that might be better addressed in another > thread: even if both of the above weren't true, this daemon uses > several sockets for multiple "roles" internally, some of which share > all low-level details (e.g. two distinct use-cases for multiple TCP > sockets that serve different high-level protocols, where the user > might choose arbitrary ports for both). I'm not seeing any trivial > way to distinguish these via socket activation - perhaps some kind of > socket "label" that could be accessed by the daemon via sd_* APIs to > distinguish would be useful here? You can use getsockopt to get some information, and match the port/type to the appropriate structure. See https://trac.torproject.org/projects/tor/ticket/8908 for a patch doing that kind of thing for tor. -- Michael Scherer _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel
