On Tuesday 20 February 2007 17:37, Jeff Dike wrote: > On Tue, Feb 20, 2007 at 04:57:40PM +0100, Jeroen van der Ham wrote: > > Is it possible to add an option to uml_switch so that it is completely > > silent? > > It would be a matter of putting all the printf's under the control of > such a switch - not a big deal. > > > I'm using UML as an educational tool to let students explore computer > > networks. However, if we create a network that contains a loop then > > uml_switch will start spamming all kinds of messages. It's not spam. Ignoring them was bad... > > Even if the uml_switch is started in daemon mode, and redirecting > > everything to /dev/null, then this still seems to be a big load for the > > terminal where it was started.
What you mean by "there seems to be a big load for the terminal"? Describe symptoms. I fear that you are seeing just CPU load. And since uml_switch does not implement (unless I'm overlooking something) the bridge* spanning tree protocol, I guess you are actually seeing packets looping through uml_switch. So this is useful to show why STP is needed. And I can guess messages are continous "Addr: X New port Y", "Addr: X New port Z", with the ports ever changing, right? Imagine a packet starting from a computer, being flooded through the network by an uml_switch and reentering this uml_switch after looping - uml_switch will not recognize the duplication. However, if you look on the archives, you'll see that there are at least 3 reimplementations of uml_switch by different authors (the one in UML is the simplest one I think). They may have better behaviour when having a loop in the network. * It's a bridge - I now recall that when you connect more than one host on a switch port, you're actually using it as bridge, not as a switch. > It shouldn't be. redirecting to /dev/null should eliminate any load on > the terminal. Obviously you want to redirect stdout and stderr, like in '&> /dev/null' or '>/dev/null 2>&1'. If you're doing this, then there cannot be output on the terminal, unless there is a bug in the shell, or you mean something else. -- Inform me of my mistakes, so I can add them to my list! Paolo Giarrusso, aka Blaisorblade http://www.user-mode-linux.org/~blaisorblade Chiacchiera con i tuoi amici in tempo reale! http://it.yahoo.com/mail_it/foot/*http://it.messenger.yahoo.com ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys-and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
