On Wed, 2005-07-13 at 08:09, Eric Dantan Rzewnicki wrote: > On Tue, Jul 12, 2005 at 01:46:13PM -0700, Fernando Lopez-Lezcano wrote: > > On Tue, 2005-07-12 at 12:56, Iain Duncan wrote: > > > >>I've just joined the list and it's pretty interesting. > > > >>Can someone tell me something about the differences between the > > > >>preempt patch from Ingo and the "Realtime Linux Security Module"? > > > >>I currently use the latter one and I'm quite satisfied as jack works > > > >>really fast. Perhaps one should try this way instead of the vanilla > > > >>kernel patch. There have to be pros and cons I'm interested in. Can > > > >>someone point them out? > > > > The LSM and Ingo's patches are addressing 2 separate issues. Ingo's > > > > patch is working to minimize sources of latency in various code paths in > > > > the kernel. The rtlimits and the realtime-lsm are addressing the issue > > > > of providing a security model for realtime applications to get the > > > > capabilities they need to run in real-time. Ordinarilly these > > > > capabilities (CAP_SET_PCAP, mlockall(), and SCHED_FIFO()) are only > > > > accessible as root. rtlimits and the realtime-lsm provide infrastructure > > > > for allowing these capabilities to be granted to only a specified set of > > > > users/processes. > > > So am I correct in believing that the preempt patch is the one that > > > makes a difference if I intend to run as root anyway? > > It makes (should make?) a difference independent of whether you run as > > root or not. If you run as root you can access everything. If you don't > > run as root (highly recommended :-) you need some additional stuff to > > get the same performance. > > > ( Yeah I know I'm > > > not supposed to, but IMO my machine is just a synthesizer in disguise as > > > a computer and I'll unplug the ethernet cable if I need to. ) > > 2.6.12 already includes the rlimits patch that will allow you to run > > well as a non-root user. But you will need a patch to pam (if your > > distro uses pam) or a special user program to access realtime scheduling > > as a non-root user (was posted not long ago to this list). > > I vaguely recall that demudi stuck with the realtime-lsm for the current > version. Is this correct? > > Are there deb packages of the patched pam available? > what about rpm's for ccrma? The latest "edge" kernels on Planet CCRMA (for fc3/fc4) use rlimits and the repository includes a matching patched pam... -- Fernando
