Hello Roger
Excerpt from Roger Leigh: -- <snip> -- >> Yes, the man page says it swaps the S for a K. >> e.g. say we have the following link: >> /etc/rc2.d/K10cups >> >> Then afaik - and please correct if i am wrong - init will call the stop part >> of >> this initscript when ever runlevel 2 is entered. So basically during each >> boot >> process. Why should we spent resources on that? >> Therefor rc-update() places those links instead only in runlevel 1 where they >> might even be useful without wasting time on them during bootup, nor >> shutdown. > > This is simply how System V init works when runlevels change. You do > need the links in each runlevel so that you stop all the necessary > services when leaving the runlevel, and then start all the necessary > services entering the new runlevel (i.e. you run all the K links in > runlevel n, and then all the S links in runlevel m). You can remove > "unnecessary" links, but then you'll find that things won't then be > stopped if you switch runlevels/shut down etc. in the "wrong" order. > > However... that's how it works traditionally. Current Debian uses > startpar to effect runlevel changes, and it has both the links and the > /etc/init.d/.depend* dependency graphs as input. It can potentially be > quite a bit cleverer in avoiding running scripts unnecessarily. I > haven't checked if it does or not though--it would be interesting to > know. > > Note that the overhead of running a script that exits immediately is > almost unnoticeable. For all but the most exceptional circumstances, > eliminating these scripts being run is not worthwhile. A quick test > on my system shows that I can run (sequentially) up to 2300 shell > scripts *per second* or (parallel) potentially around 8 times that, > i.e. over 18000. This is a decent system, but even on a slower system, > it's not worth optimising stuff that's lost in the noise--there are far > greater things that slow stuff down--like actually starting and stopping > stuff--and this is all parallelised now anyhow. If you were to optimise > this, you'd save a tiny fraction of a second. Thank you for the insight. This is interesting. I will keep this in mind, though i probably wont send another update of rc-update() to this list as people are getting bored presumably. Thanks. -- Regards, Thilo 4096R/0xC70B1A8F 721B 1BA0 095C 1ABA 3FC6 7C18 89A4 A2A0 C70B 1A8F -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/kkp94l$4ud$1...@ger.gmane.org
