Hi everybody, I have repeated the test using a parallel stress test (dd if=/dev/sda of=/dev/null, I have a SATA harddisk). The results are that my RTAI latency of 4µs is not valid, here the latency is about 26µs. However, xenomai shows a higher latency of about 40µs. The interesting thing is, that without load RTAI seems to run very long in a very low latency region, at the same setup xenomai shows large latencies earlier.
Well, I have repeated these tests on a different PC that has a server mainboard and a Pentium D 4 (real dual core) CPU. The results (measured under load) are much better here: RTAI shows a latency of about 6µs Xenomai shows a latency of about 10µs. Both values are acceptable, however I wonder where the difference comes from? Thanks for all the feedback on that issue! Regards Mathias > > I have rebuild my system using V2.2.4 of xenomai. > > Also, I had a look to reuse the kernel configuration from the 2.4.33 RTAI > system. > > However, the results are more or less the same. > > The only kernel module I have loaded is the "tg3" network driver, the > chipset of the > > PC (ICH6) is supported by the SMI detection and it is activated. > > > > On such hw, you may want to enable the following: > CONFIG_BLK_DEV_IDEDMA_PCI=y > CONFIG_BLK_DEV_IDEDMA=y > CONFIG_IDEDMA_AUTO=y > > > I have enclosed my kernel configuration, perhaps this can help to identify > an issue. > > I do not have X11 running, it is a text-mode only system that is > controlled via telnet from > > another PC. > > > > I'll try to do a stress test on the RTAI system as well. > > > > You could try running RTAI 3.3 over 2.6.17 with the very same config > file too (Xenomai opts aside, of course), so you could rule out any > configuration problem if the gap still exists. -- 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 44,85 inkl. DSL- und ISDN-Grundgebühr! http://www.arcor.de/rd/emf-dsl-2 _______________________________________________ Xenomai-help mailing list [email protected] https://mail.gna.org/listinfo/xenomai-help
