Hi Jan, > > I have tried the latest 2.6.21 kernel + Ingo Molnar's realtime preempt > patch > > (see: http://rt.wiki.kernel.org/index.php/RT_PREEMPT_HOWTO) > > > > And I am really amazed about the results. > > On my Pentium 4D (dual core) system, 3.2 GHz, I ran the cyclictest > > application (which is something similar to the "latency" application of > Xenomai/RTAI) > > and I get values below 15 microseconds on my PC (for a single task running > with 200 microseconds). > > .... > > > > Currently, my application is working quite nice using Xenomai/rtnet > however there are some > > drawbacks like the issue with limited IRQs: Sharing of IRQs between > Ethernet-Drivers of rtnet > > and non-realtime drivers is not possible (at least I did not manage > that...). > > A smooth usage of real time features from a "standard" kernel could help > here! > > Nope, not really. As I think to have explained earlier, IRQ sharing > between drivers that are designed for real-time and others that are not > will never work deterministically. That has nothing to do with the > design of your RTOS underneath. Actually, the same issue once came up > for -rt over some ARM board that did poor IRQ line sharing as well. > > Jan I agree, the best is actually to have separate IRQs for real time and non real time drivers. However, reality shows me, that this is very hard to get with standard PCs. I can plug in one or two PCI boards to have an unique IRQ for them. However, if I want to use more PCI boards IRQ sharing cannot be avoided. As with the preempt patch, the duration of non-realtime IRQ routines seems to be fairly short. >From this, I think it is at least an option to share IRQs between real time >and non real time drivers even if the IRQ routine of the non real time driver may lead to a delay of the real time IRQ routine. It is a question of acceptable delays for the IRQs.
Regards Mathias -- Mathias Koehrer [EMAIL PROTECTED] Viel oder wenig? Schnell oder langsam? Unbegrenzt surfen + telefonieren ohne Zeit- und Volumenbegrenzung? DAS TOP ANGEBOT JETZT bei Arcor: günstig und schnell mit DSL - das All-Inclusive-Paket für clevere Doppel-Sparer, nur 39,85 inkl. DSL- und ISDN-Grundgebühr! http://www.arcor.de/rd/emf-dsl-2 ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ RTnet-users mailing list RTnet-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/rtnet-users
